# Question
Title: Is this 2B vs. N endgame won for the bishops?
Tim Krabbe gives this position on his list of serious promotions to rook and bishop:

```
[FEN "8/8/5b2/8/K7/4N3/kp6/8 w - - 0 1"]
[White "Boniface"]
[Black "Pugh"]
[Site "Bristol"]
[Date "1995"]

1. Nd1 b1=B

```

And states that: "Although the position was then technically won for Black, he did not manage to win, and a draw was agreed at move 92."

Can black win the resulting 2 bishops vs knight ending, and if so can it be done within 50 moves to avoid a draw? I had Stockfish 5 grind at it for almost two hours and a depth of 83 but it couldn't find a win.

# Answer
> 6 votes
Try Syzygy tablebase: https://syzygy-tables.info/?fen=8/8/5b2/8/K7/8/k7/1b1N4\_w\_-\_-\_0\_1

Please ignore DTZ if you don't know what it is, look at DTM. It's **checkmate in 139 piles** with perfect play.

No, the position is drawn under the FIDE 50-move rule.

# Answer
> 2 votes
I would suggest running Tablebase on the position - the program can calculate exactly how many moves until the end, provided there are six or less pieces.

In practical play, it is one of those endgames that borders on the brink between a draw and a win. It should be a draw with **constant** perfect play, but in practice it is much easier to win with the 2 B's than draw with in the one Knight.

I think even Karpov failed to draw this endgame in a game he had with Kasparov, and he was renowned for his incredible technique.

# Answer
> 1 votes
http://www.thechessworld.com/resources/nalimov-endgame-tables

Per Nalimov Endgme Tablebases the endgame of K+2B vs. K+N is a force win for the 2Bs in a maximum of 67 moves.

---
Tags: endgame, pawn-promotion, bishop-pair
---


# Question
Title: How many places can the queen move at each position?
For each square on the board, how many moves could a queen on that space move, including not moving?

Ideally I'd like to see this visualized but I understand if that's not possible.

# Answer
It depends on the square, but simple counting (along the rows, columns and diagonals) reveals that this is the answer:

```
22 22 22 22 22 22 22 22
22 24 24 24 24 24 24 22
22 24 26 26 26 26 24 22
22 24 26 28 28 26 24 22
22 24 26 28 28 26 24 22
22 24 26 26 26 26 24 22
22 24 24 24 24 24 24 22
22 22 22 22 22 22 22 22

```

You see that in the center, the queen controls the most squares. I'm more familiar with a similar diagram counting the number of squares a queen controls (excluding the square itself):

```
21 21 21 21 21 21 21 21
21 23 23 23 23 23 23 21
21 23 25 25 25 25 23 21
21 23 25 27 27 25 23 21
21 23 25 27 27 25 23 21
21 23 25 25 25 25 23 21
21 23 23 23 23 23 23 21
21 21 21 21 21 21 21 21

```

This is a superposition of the diagram for a bishop:

```
 7  7  7  7  7  7  7  7
 7  9  9  9  9  9  9  7
 7  9 11 11 11 11  9  7
 7  9 11 13 13 11  9  7
 7  9 11 13 13 11  9  7
 7  9 11 11 11 11  9  7
 7  9  9  9  9  9  9  7
 7  7  7  7  7  7  7  7

```

and the one for a rook, which is very simple, and a good illustration why rooks aren't at home in the center like most other pieces:

```
14 14 14 14 14 14 14 14
14 14 14 14 14 14 14 14
14 14 14 14 14 14 14 14
14 14 14 14 14 14 14 14
14 14 14 14 14 14 14 14
14 14 14 14 14 14 14 14
14 14 14 14 14 14 14 14
14 14 14 14 14 14 14 14

```
> 4 votes

# Answer
It would depend on which square the Queen is. If the Queen was in on of the corner squares, it could move to the least squares possible. If the Queen was in one of the center squares, it could move to the most squares possible.
> 1 votes

---
Tags: queens
---


# Question
Title: Do you find websites like chesstempo useful for improving tactical skills?
I've been using chesstempo for quite a while solving lots of problems per day. What I noticed is that I don't feel that my tactical skills were improving. My results in tournament games were not improving either.

However chesstempo's estimate of my rating is more or less accurate (around 1950).

So the question is - did such websites help you to improve your tactic skills? if so, how many positions/hours per day were you solving? Did they provide accurate estimation of your rating (comparing to your real-life rating)?

# Answer
I have not played enough or practiced enough on ChessTempo to really notice a difference in my tactical ability, but I am probably certain that if you spend enough time and I am not sure how long this is (it varies for each person) that your tactical skill will improve over time. I also never paid attention to my rating on ChessTempo as I do not know what my actual rating is.

One thing I am certain of is that ChessTempo and other similar websites or puzzles in books will teach you to stop and think before making a move no matter what or will teach you to look for a tactic — whereas before, I would make the first move I saw without thinking.

In the end, it probably does improve your tactical skills, you just have to be patient and not assume that your tactical skills are not improving by the number of games you win or lose. We often grade ourselves on whether we win or lose and I believe this is a big NO-NO. Especially if we lose, we often assume that we have not improved tactically, strategically, etc.
> 14 votes

# Answer
I am a volunteer chess coach in a couple Dallas Inner-city schools (a middle school and a high school). I am a mediocre player with a standard tactics problem rating of about 1400. Because I cannot give significant individual attention to 25 students with varying degrees of chess skill, I have utilized chesstempo extensively and have encouraged all of the chess club players to work standard tactics problems to improve their games. Largely as a result of this activity, our two chess clubs have managed to win several first, second and third place trophies as team and individual players in the city school district. Some of the students have worked over 3000 tactics problems. Many of them beat me regularly online and on the boards. Our best player has a chesstempo rating in the mid-1500s and he works problems approximately four times as quickly as I do. I firmly believe that an interest in chesstempo is a big factor in the success of many of our best players.

One big advantage of chesstempo that by playing virtually all of our club games on line the club members can play at their convenience. This allows them to play a lot more chess than if they could only play once or twice a week during our regular after school club meetings. It also gives me the opportunity to look at accurate records of their games and show them their strengths and weaknesses. I can then create a database that includes every club game that each member plays.

We are currently running an asynchronous inter-mural tournament (two schools in the same general neighborhood) on chesstempo in which 28 contestants are each playing 27 simultaneous games over a 60-day period. Thus they will log 378 games against each other and will have the privilege of playing every other interested club player. At this point in the tournament our strongest (and leading) player, a ninth grade student from Afghanistan, has won about fifteen games and has not lost or drawn a game. Eighteen months ago he had a mere understanding of how to move the pieces. Our players currently include 4th graders to 10th graders.
> 11 votes

# Answer
Perhaps it isn't the frequency of your usage, but the way of using it. Are you happy with your chesstempo tactics rating? If your rating has been stagnant for a while, find out why: do you have trouble with a certain problem-type? Or give up on problems after a certain time? While the free version of Chesstempo doesn't offer targeted tactics, you can certainly deal with the second problem by just not quitting. Take an hour or more if need be, but make sure that you're completely satisfied with your solution before playing out the moves. This got me from 17-1800 to 2100 on chesstempo, and helped greatly in tournaments. Also, if your playing strength is about 1900-2000, then tactics might not be the only reason for not getting better tournament results.
> 6 votes

# Answer
Generally solving tactics puzzles should be part of every player's training schedule. There can be several reasons why this did not help your tournament games:

* Perhaps your play is limited by other factors (opening, endgame, strategy, ...), which you need to focus on!?
* Perhaps you have a problem recognizing when it is time for tactics!? If you only solve problems on sites like chesstempo, you already know beforehand that something is possible which is a big advantage over the real game situation.

Also, in my experience, tactics training has the biggest effect on tournament play for beginners. At your level, you (and your typical opponents) should be already familiar with most tactical motives and most games are likely not decided by simple tactics. This does not mean that you should ignore tactics completely, but analyzing your own games should help you to find out your weaknesses and work on them.

It has been some time that I used chesstempo, so I don't remember exactly what kind of problems they have. For somebody familiar with tactical motives, I would look for more realistic/messy problems instead of streamlined/simplified versions. This will teach you to also consider defensive resources of your opponent, or teach you to decide between several promising continuations and also it is closer to the real tournament games. I know that the problems on lichess are taken from real games and that those on chess24 also include problems where you start from a worse position and have to find a way to draw. Both of these features I consider useful and they might exist on other websites as well.
> 2 votes

# Answer
The Question is not about how many Tactical Puzzles you were able to solve on ChessTempo but in your real games whether you were you able to bring out same kind of Positions .

There are a lot of Players who practice Tactical Puzzles day in & out and their rating does not take a major stand according to their expectations . Studies have revealed even if you practice some 1000 puzzles also with in 5-10 days doing nothing else your rating would stand the same or differ by a small margin for some people . The reason is even if you practiced those puzzles you got to take care of the Piece placement . When you solve a Tactical Puzzle you knew that there is a combination and the pieces are on the best squares which actually does not happen in majority of games . You need to focus on the Activity of the Pieces which is the original aspect in any Chess Game . Follow games of Players like Kasparov/Fischer/Alekhine and you will see how they carry out the attack instead of just solving the final combination.
> 1 votes

# Answer
I have not solved too many Puzzles from ChessTempo but other Websites like Chess.com and Chessgames provide 5 and 1 puzzle each day respectively . There are always two kinds of tactical puzzles what I have noticed . One is from the real games and the other is a puzzle which is manually set up to improve the Calculation Skills . The ones which are from real games I believe they are well enough to improve your ratings and even help you in pattern recognitions .The other is just for improving calculations .
> 0 votes

---
Tags: learning, tactics
---


# Question
Title: How many steps can a grandmaster foresee?
What makes a grandmaster special? Is it the amount of steps the grandmaster can foresee, or the creativity? How many steps can a grandmaster foresee in average in a game (for instance Carlsen and Ivanchuk)? Is there a minimum amount?

# Answer
> 17 votes
This depends a lot on the position and cannot be answered generally. If you have a forced line, i.e. a position where there are only few candidate moves at every step, a grandmaster can calculate many moves. I am reluctant to give a concrete number because it really depends, but to give you a rough idea, let's say 20 moves.

On the other hand if the position is rather closed, of the maneuvering type, with many equal alternatives at every step, the calculation depth will be much smaller, simply because the number of variations will be much much larger in this case. And even if you calculated 20 moves deep you might not come to a conclusion on which line is best, because 20 moves in the future the position might still be equal. In this case a grandmaster would typically only calculate a couple of moves deep (if at all) in order to check that he is not blundering anything to a tactic.

As you can see from this description, pure calculation strength is only needed sometimes in a game and certainly not the only reason that grandmasters are much better than the rest. Unlike computers, humans **do not** play chess by calculating many moves in advance. The strength of human players over computers is that they can *evaluate* the position and *develop a plan* based on the evaluation. Humans focus more on recognizing patterns and play moves based on these patterns.

So, grandmasters are grandmasters, because they are good at all parts of the game:

* calculating many moves ahead
* evaluating a position correctly
* finding the right plan
* good at defense: using tactical ideas, standard methods, pure calculation...)
* good at openings: knowing main lines, side lines, recognizing wrong moves in an opening and knowing how to react to them, knowing the ideas behind openings...
* good at endgames: as with openings, there is a huge body of theory that you can study; also some grandmasters like Carlsen, are said to be particularly good at endgames beyond the known theory
* pattern recognition abilities: to recognize tactics and other known motives
* creativity
* personal traits, physical fitness

# Answer
> 10 votes
**It depends upon the position**.

For a simple endgame, grandmasters use shortcuts to see very far. For example, using the rule of the square, a grandmaster can see 7 moves. Combining other shortcuts like this, they can see 15 or more moves ahead.

In middlegames with few tactics, GM Soltis argued in *Studying Chess Made Easy* that seeing 2 1/2 moves ahead was sufficient for grandmasters to find a good move.

# Answer
> 6 votes
It entirely depends on the position and number of variations. For example, if there is a forced line (where both sides only have one option on each move in a line), then grandmasters can calculate 20 or 30 moves ahead without much trouble.

But if each side has multiple choices on each move, grandmasters can not calculate nearly as much, since the number of possible positions grows exponentially. Think of the number of variations as a tree - if both sides have two choices on each move, the tree grows two new branches at each branch. You can see how this would become very large quickly.

In general though, most positions do not require extensive calculation - on most of their moves, Grandmasters only calculate 4-5 moves ahead... mainly to just make sure their idea works. They would only need to calculate many moves when they're in an intense tactical battle, which usually only happens once or twice in a game (since the winner of the tactical skirmish usually wins the game shortly after).

What makes a grandmaster special is a number of things. The ability to calculate many moves is definitely one trait, but there are many other traits as well:

* Evaluating a position to find the correct plan.
* Pattern recognition abilities (the quickly recognize tactics or well known strategic plans during a game).
* Raw talent - many people work very hard at the game, but only 0.1% of those people actually make it to grandmaster level.
* Competitive spirit and the will to win - this one is definitely important in competitive tournaments. The burning desire to win is important to succeed in chess, even though it may be somewhat unhealthy to have in real life :)

# Answer
> 0 votes
Grandmasters follow many Chess principles which sometimes reduce the amount of Calculations in the game.

1. When the Position is Tactical and lot of forcing moves are compelled they can calculate up to 15-20 moves in different variations.
2. Please note that they do not pick up all the combinations as an amateur tries to do but they calculate the important lines. Now you may ask how they choose the important lines. After the calculation they have already visualized the basic aspects like their own King safety, piece placement, etc.
3. There is a Principle of Elimination method which helps them to reduce the unimportant lines and selection of candidate moves.
4. They choose their openings which they can memorize for 20 moves on average, and they know the clear ideas in the middlegame. For example, if a GM plays the Sicilian Najdorf as Black, he knows that Black's idea is to play on the c-file, attack on the Q-side and play in the Centre. They know the aspects of the middle game when they choose an opening. They even study 100s of games on that particular line.
5. One characteristic is that they believe if their pieces are on good squares and positionally sound, it helps to reduce calculations. As Carlsen said during his WCC match against Anand, "My pieces are on better squares compared to his, so why I should be afraid of losing?" This, I believe, is a great lesson for all.

---
Tags: grandmaster
---


title: What website is this?

text:
# Question
Title: What website is this?
Someone sent me a screenshot of a chess website with detailed analysis. What is this website? Where does it come from? It doesn't look like lichess to me, I have no idea.

# Answer
The board here looks similar: http://analysis.sesse.net
> 2 votes

---
Tags: online-chess
---


# Question
Title: Considering Scandinavian defense versus Dutch defense
If the game had played between to GM which game progresses to more steps if pgn notion tends more defensive approach with less blunders.

Just for recap

Scandinavian defense `ECO B01`

```
[fen ""]
1. e4 d5

```

Dutch defense `ECO A80`

```
[fen ""]
1.d4 f5

```

Both openings are quite unbalancing. Which opening would lead to a longer game, and why would this be so?

# Answer
> 5 votes
I am still not sure whether this answers your question, but: Scandinavian tends to lead to more open/tactical games while the Dutch tends to lead to more closed/positional games. If you want to profile openings I suggest to take a database and check game positions of master players around move 10-15 and see whether you like any of those positions.

But anyway (and this is not meant to be condescending; I know I wrote this before to one of your other questions): if you want to improve in chess forget about all those openings for the time being and focus on not losing pieces in one move. This will give you much better chess than if you learn some opening lines by heart, without understanding the ideas behind the openings. As a second step, learn some general principles (good, bad pieces, development, ...) At move 16 both players blundered their queen and worrying about opening theory at this level is-to be honest-a waste of time.

---
Tags: analysis, scandinavian-defense, dutch-defense
---


# Question
Title: Looking for books specializing in chess play from black
I play online chess at a popular site and while playing from black, I win 58% of my games. I think I have a natural tendency to be a 'counterpuncher'. I seem to derive a perverse enjoyment in playing as the underdog and find it ammusing on some level to be able to survive my opponent's best attack. I'm a 1720 rated player in the 84th percentile of 30k players using E.L.O rating system. I'd like to advance my knowledge from black but can't find much devoted material. I'm guessing my otb play would be 1500-1600.

# Answer
1. *Black is OK!*
2. *Black is Still OK!*
3. *Black is OK Forever!*

All books are by András Adorján.

A sample, Black is OK, or the Presumption of Innocence in Chess:

> In criminal law, the suspect is entitled to the presumption of innocence until it is proved beyond reasonable doubt that he is guilty. It might help me a lot if I was well-versed in law, but perhaps it would also make my argumentation bloody boring. So what am I getting at is that we should try to take an unbiased approach, and think of the starting position of the chess game. BLACK does NOT have to equalise, as it is not BLACK who has to prove anything in the first place! I presume - in the spirit of the presumption of innocence - that the position is equal. It is White who has to prove that he can get an advantage. And, as he has the right to move first, he sees to it immediately. Naturally, starting the game should not be mistaken for taking the initiative!
> 14 votes

# Answer
It was my pleasure and recognition to see somebody asking to recommend some books how to play with BLACK. They were suggesting 3 books. All of them happened to be mine:

* *Black is OK!* (1988),
* *Black is still OK!*
* *Black is OK forever!*

It shows the good taste of the members... Gratefully I draw your attention to some more. *Winning with the Gruenfeld* (Batsford, 1986) which could not be a BLACK is OK! book by name, for this "Winning with ..." was a Batsford series. But I assure it qualifies by the content. Finally there is a *Sicilian subvariations* (1994) which appeared in 5 languages simultaneously. And last there is a 'Rare Openings' book (English, Deutsch, French) which deals with everything but 1.d4, 1.e4, 1.c4 and 1.Nf3. I'm glad to join you and look forward to receive your comments, thoughts, etc.

I'm waiting for your messages too in: aa\_ok@interware.hu ADORJÁN András
> 16 votes

# Answer
i have a book called winning with the najdorf, it's pretty good, for white and black.
> 3 votes

# Answer
It's a rather old book, Barnes and Noble or amazon.com may have it. Fred Reinfeld's "Attack and Counter Attack in Chess" has a section entitled: From Black's point of view.
> 3 votes

# Answer
The books of Victor Korchnoi the archetypal counterpuncher himself -

Chess is my life (1977)

My best games : with Black (2002)

Korchnoi's 400 best games (1978)

And what IGM\_AA said.
> 2 votes

# Answer
I highly recommend *The Sniper* by Charlie Storey.

The publisher's blurb says:

> The Sniper is a dynamic and universal opening weapon for Black which can be used against all mainline openings. Black's system of development with ...g6 and ...Bg7 initially allows White to occupy the centre but, in true hypermodern style, Black strikes back immediately with ...c5. The Sniper can lead to original or barely-known positions in which Black can strive for the initiative. It's also rich in move-order possibilities, with potential transpositions into Sicilian, King's Indian or Benko-type positions.

In my opinion the book delivers what it claims.
> 2 votes

---
Tags: online-chess
---


# Question
Title: Is there any way to gain equality with the QGD Marshall Defence?
The Marshall defence goes **1. d4 d5 2. c4 Nf6?!**

I played this game recently as white. It was the first time I saw the Marshall in a game and the real contest was over by move 14.

```
[FEN ""]
[StartPly "7"]

1. d4 d5 2. c4 Nf6 3. cxd5 Nxd5 4. Nf3 Bg4 5. e4 Nb6 6. Be2 Bxf3 7. Bxf3 e6 8. O-O Be7 9. d5 O-O 10. dxe6 fxe6 11. Qb3 Qd7 12. Bg4 Rf6 13. Rd1 Bd6 14. e5 Rg6 15. exd6 Rxg4 16. dxc7 Rd4 17. Rxd4 Qxd4 18. Qxe6+ Kf8 19. c8=R+ Nxc8 20. Qxc8+ Ke7 21. Qxb7+ Kf6 22. Qf3+ Ke6 23. Qe3+ Qe5 24. Nc3 Nc6 25. f4 Qxe3+ 26. Bxe3 a5 27. Rd1 Ne7 28. Nb5 Rb8 29. a4 Nd5 30. g4 Nxe3 31. Re1 Rf8 32. Rxe3+ Kd7 33. f5 g6 34. Rf3 Kc6 35. Kg2 gxf5 36. Rxf5 Rg8 37. Kf3 Rd8 38. Kg3 Rd3+ 39. Rf3 Rd2 40. b3 Rb2 41. Na3 Ra2 42. Nc4  1-0

```

Now the Marshall defence is considered to be dubious, even refuted:

> This \[1. d4 d5 2. c4 Nf6?! 3. cxd5 Nxd5 4. Nf3!\] is considered to be the refutation for this defence

Source: GreenCastleBlock on YouTube, @ 0:58.

But my question is **there any move after 4. Nf3 where black gains equality?**

# Answer
The Marshall is considered dubious since Black essentially just gives up full control over the center. For that reason, there is no move that would give Black absolute equality after 4. Nf3

There are probably good development schemes that would give Black a playable game, but there is no direct path to absolute equality. Heck, there's no direct path to complete equality for Black in even the most respected openings, such as the Grunfeld and Slav. Even in those openings Black has to work to achieve an equal game.

The best development scheme that I know of in the Marshall is the following (after 4. Nf3):

g6, Bg7, 0-0, Nc6, Bg4. And if White plays e4 at any point, the Knight on d5 retreats to b6. This gives Black a reasonable game, and I believe it is the most popular system in the reference database. But even here, White keeps a comfortable edge.
> 3 votes

---
Tags: opening, queens-gambit, refuted, queens-gambit-declined
---


# Question
Title: Why ...g6 before ...Bxa6 in the Benko Gambit?
```
[FEN ""]

1.d4 Nf6 2.c4 c5 3.d5 b5 4.cxb5 a6 5.bxa6 g6 6.Nc3 Bxa6

```

This is a main line of the Benko Gambit. Black could also have played 5...Bxa6, followed by 6...g6 to get the same position.

However, 5...Bxa6 is played only half as often as 5...g6, and the majority of those games go 6.Nc3 d6 in my database, more often than 6...g6. So to reach the game position, g6+Bxa6 is about four times as popular as Bxa6+g6.

Is there some minor detail that makes 5...Bxa6, 6...g6 less attractive?

# Answer
> 2 votes
No, there are no real differences between the 2 lines. White has no way to defend the pawn, so black can choose the move order they feel most comfortable with.

You see something similar in the french defence:

```
[FEN ""]

1. e4 e6 2. d4 d5 3. e5 c5 4. dxc5 Nc6

```

Black could have regained a pawn straightaway with 4...Bc5, but decided to develop a knight first, seeing as white has no way to defend that pawn.

**Edit**

I found this explanation of 5...g6 on wikipedia

> The main line continues with the moves 4. cxb5 a6 5. bxa6 Bxa6 followed by Black fianchettoing the f8-bishop. (Black players leery of the double-fianchetto system, where White plays g3 and b3, and fianchettos both bishops, have preferred 5...g6 intending 6.b3 Bg7 7.Bb2 Nxa6! The point is that it is awkward for White to meet the threat of ...Nb4, hitting d5 and a2, when Nc3 may often be met by ...Nfxd5 because of the latent pin down the long diagonal.)

The double fianchetto has fallen out of favour seeing as the king's walk variation gives a good game for white.

# Answer
> 1 votes
There is technically as such not such a great difference but it implies a Basic Chess principle . Development of the Dark Square Bishop on Long diagonal ASAP . Black knows that the Pawn on a6 is not going anywhere . He waits to capture either with Knight or Bishop or even Rook sometimes . Playing g6 Black makes the way for castling or makes some space for his King on f8

---
Tags: opening, benko-gambit
---


# Question
Title: What happens if you move your king on stalemate?
Let's say the following happens during a blitz match:

* White makes a move, resulting in stalemate
* Black doesn't notice the stalemate and moves the king into an illegal position.

Usually illegal moves result in instant loss according to FIDE rules, but a stalemate results in instant draw. So, what's the outcome of the game? Draw or win for white?

This didn't happen in one of my matches, but I've had some losses in the past because of illegal moves and I'm wondering what would happen in this case.

# Answer
> 10 votes
Just like checkmate, stalemate *immediately ends the game*. From the FIDE Laws of Chess, 5.2a:

> The game is drawn when the player to move has no legal move and his king is not in check. The game is said to end in ‘stalemate’. This immediately ends the game,
> provided that the move producing the stalemate position was legal.

This is not overridden by any rules in Appendix B, covering Blitz, so the situation you describe is a draw.

---
Tags: rules, stalemate
---


# Question
Title: What is the disadvantage of the move 3. ..h6 in the Queen's Gambit Declined?
One of my opponents keep playing `1. d4 d5 2. c4 e6 3. Nf3 h6!?` against me. Thus avoiding the main lines of the Queen's Gambit Declined that start after the normal `3) ..Nf6 4. Bg5 Be7 5. Nc3` etc.

Is there any disadvantage of the move `3) ..h6` that White may try to exploit? And if `3) ..h6` was a playable move for Black then why it is so seldom played?

I had a look at my database and I found a meager 32 games starting with `1. d4 d5 2. c4 e6 3. Nf3 h6`, those are played by the lower rated players only. For the part of comparison, the Albin-Counter Gambit I have found are 100x games. Surely there must be a reason why it is so seldom played?

I understand that Black should try to develop the pieces in the opening firstly and `3) ..h6` doesn't look so terrible active, but on the other hand, the position is quite closed and after e.g. `4. Nc3 Nf6 5. Bf4 (I do not want to shut the Bishop with 5. e3) 5 .. Bd6!?`, now the Black catches up in development and has a very solid position. What would you play instead?

```

[FEN ""]
1. d4 d5 2. c4 e6 3. Nf3 h6!?

```

# Answer
I suspect that a good try for white here is to go into Colle-Zukertort system: http://en.wikipedia.org/wiki/Colle\_System#Colle.E2.80.93Zukertort\_System

Then 3...h6 is not only a tempo loss, but also a unpleasant weakness of the king side.
> 2 votes

# Answer
There is no instant refutation to 3...h6?!. Your PV with 5...Bd6 gives white his usual opening advantage, as the "bad" c1-bishop has traded for black's "good" one, so there is no reason to reject that line - 1.d4 d5 2.c4 e6 3.Nf3 h6 4.Nc3 Nf6 5.Bf4 Bd6 6.Bxd6 Qxd6 +/=. If you are intent on proving ...h6 to be a waste, however, you might try 4.g3, where ...h6 is worthless in the Catalan. But then 4...Bd6 and the c1-bishop is looking cramped in.

As for the positional disadvantages of ...h6, it weakens black's kingside and does not develop.

Also, just because a move is not a book move does not mean it is bad. It could be playable, but just inaccurate.
> 1 votes

# Answer
3...h6 is a waste of time. At most it threatens g5, which if it were important, could be circumvented by h4. In this case the best move might be 4.Nc3. It continues your development and already threatens e4. Do not worry about 5.e3. After moves like Bd3, Kg1, and Re1, e4 will be unstoppable.
> 0 votes

# Answer
In Chess there is a saying " A Weakness is not a weakness unless it is exploited or it can be exploited."

Well the move h6 does not look a good move at all because it just deprives the White Black Bishop coming into g5 . It does not develop anything from Black's perspective but it weakens the g6 Square somehow . If White understands this then he can play e3/e4 , bring the Knight to e5 and then do a sacrifice on f7 and Qh5+,Bd3 can make the game difficult for Black . Black will be running away with his King in the entire game . I understand that Black will develop his Knight on f6 which would take the h5 Square but that can be dislodged by playing e4 ,d*e4 and then N*e4. The above explanation is quite imaginary but nevertheless can be applied in some games depending on a lower level opponent ELO.

Now this is absolutely true :

Playing h6 prevents many important lines of QGD like Barmen, Lasker, Miles and many other variations where Bishop comes on g5 White can instead play the Harrwitz Attack where he can bring the Bishop on f4 and try for a K-side attack or even the London System and advance the h4 Pawn , Ng5 which can serve a nice line for this h6 move .
> 0 votes

---
Tags: opening, analysis, theory, queens-gambit, queens-gambit-declined
---


# Question
Title: When did the light-on-the-right convention ascend to dominance?
I came upon the following wonderful painting by Sofonisba Anguissola, ‘The first great woman artist of the renaissance,’ of her sisters playing chess (painted 1555).

The painting is truly sublime. Chess players will notice, however, that the color of the squares on the board is the opposite from what is usually used in modern games, with light on the right, and so it made me wonder about the history of this convention. When did the light-on-the-right convention come into prominence? Has it been long established that way? Is this painting illustrating a different custom at that time, or rather might it be explained by an artist inventing a scene and not aware of the custom?

# Answer
> 4 votes
Sometimes chess textbooks would rotate the board by 90 degrees, under the assumption that the players sat at the left and right of the board:

> The only clear evidence of the use of different sources is supplied by the diagrams. While the great majority are oriented in the way universally followed in modern text-books, a small number in each work are at right angles to the ordinary arrangement. These must have been derived from an MS \[manuscript\], in which the positions were drawn on the supposition that the players were seated to the right and left of the board.

Source: *A History of Chess: The Original 1913 Edition* by H.J.R. Murray

Murray unfortunately does not give the origins of 'light on right'.

---
Tags: rules, history
---


# Question
Title: Is the TSCP chess engine able to run on a 32 bit processor?
I'm a beginner learning about chess engines and would like to find a chess engine written in C (like TSCP) that doesn't use bitboards for board representation because I want to test the engine on a 32 bit processor. Though I can tell TSCP doesn't use bitboard, I'd really appreciate it if anyone can clarify for me if TSCP requires a 32 or 64 bit processor to run. Thanks!

# Answer
Although pretty much everything even a mobile phone runs on the 64 bits, there is no reason why TSCP can't be run on a 32 bits architecture. In fact, it was written before 64 bits became common. TSCP can be run on any architecture as long as you can compile it, there is no platform-dependent code.

Bitboard is simply a 64-bits integer, that doesn't mean you can't use it on a 32-bits machine. Your machine would need at least an extra instruction cycle to transfer a 64-bit integer on a 32 bit machine, but everything still works.
> 1 votes

# Answer
TL;DR **Absolutely!!**

In fact, I see no reason why it will not run on a microcontroller. Possibly a side project for someone to do one day.

It should work fine (as it says it requires less than 64KB of RAM) which on a PC is already provided. :D

As for the 64-bit integers, where are you seeing those? Didn't see that in my copy of the code.
> 0 votes

---
Tags: engines, software, programming
---


# Question
Title: My chess AI makes the same repeated moves
I've built a chess game engine using Minimax and when I play AI against the AI, everything goes fine(for sometime) until both the AI players make the same set of moves again and again.

Observe the moves made by the AI players in the move-log(Right panel).

How do I eliminate this scenario?

# Answer
> 5 votes
Unfortunately, the only right answer to "How do I eliminate this scenario" is "fix your algorithm." Yes, you could implement the 3-fold repetition rule, but you should also figure out what it tells you about your algorithm.

This sort of repetition happens when there is an oscillating pattern that arises in your scoring. Think of it like rock paper scissors. White makes move to try to achieve a rock position, so black tries to make a counter-move that turns it into a paper position. Then white tries to create a scissors position and black replies by creating a rock position.

The only way to fix this is to look at your algorithm, and make the algorithm better. My advice is to put your chess program into a debug mode and have it dump out an analysis of what it is "thinking" with each move. Look at the factors which lead up to your final score, and understand how they're acting.

Once you understand why the algorithm is doing what it's doing, you can fix it. Look at the game and decide what move you'd rather see them do, and why you like that move. See if you can add additional scoring which encourages the type of play you want to see.

One thing in particular I've seen that can cause this sort of behavior is a discontinuity on the horizon. If your scoring stops at your ply limit, and that position looks good from black's perspective, looking one ply further may show a good position for white instead! This, of course, will always happen in real life, but you can try to minimize how often it happens by doing a better job of scoring each position.

If all else fails, a little randomness can help nudge the game along. One mode I implemented when I had to write one of these programs was a variable depth algorithm. Sometimes it would look at 100,000 positions before making a decision, other times it might make 200,000. That decreased the probability that I would run into a simple issue just past my horizon, because my horizon kept moving. Instead, I might blunder into the bad move, but at least the game moved forward!

# Answer
> 1 votes
You may want to consider third-repetition in your search. Stockfish does that:

https://github.com/official-stockfish/Stockfish/blob/30c583204f97da2c67b5042c30327013e70ae209/src/search.cpp

```
    // Step 2. Check for aborted search and immediate draw
    if (Signals.stop.load(std::memory_order_relaxed) || pos.is_draw(ss->ply) || ss->ply >= MAX_PLY)
        return ss->ply >= MAX_PLY && !inCheck ? evaluate(pos)
                                              : DrawValue[pos.side_to_move()];

```

https://github.com/official-stockfish/Stockfish/blob/master/src/position.cpp

```
/// Position::is_draw() tests whether the position is drawn by 50-move rule
/// or by repetition. It does not detect stalemates.

bool Position::is_draw(int ply) const {

```

Implementing third-repetition is important, otherwise your engine might waste moves and think it can still keep the advantage after some meaningless checks.

**EDITED**

You should implement the check, otherwise your engine doesn't know the move it tries to make is just simple repetition draw. You will need to program the knowledge. Someone else had the problem like you:

> http://talkchess.com/forum/viewtopic.php?t=59322&highlight=move+repetitions

# Answer
> -1 votes
Even top level engines could do this if they evaluate the position to be completely equal. If your AIs evaluate this position to be equal, then there's nothing wrong with a three fold. But in the position you posted it doesn't make much sense for White to go for a three fold, considering the 7 point advantage.

Do your AIs do this in every game, or does it just happen once in a while? What you could try is to build a method in your code called "Evaluate". It finds the rough evaluation of the position, and if one AI is better then it should not repeat moves. You could do this by making it not repeat the move it made two moves ago. So at: Rg7 Ke6 Rg6 Kd7, since the position has repeated itself call the Evaluate method. If the Evaluate method returns that White is ahead, do not let the AI repeat the move it made two moves ago (Rg7).

---
Tags: engines, programming, chess-algorithms
---


# Question
Title: Deleting multiple games from a large PGN file
I have spent around half an hour searching Google and I have not found what I am looking for -perhaps I did recognise it as what I needed if I had come across it. I have just recently downloaded SCID and decided to add all of my games from Chess.com as a starter to a database.

After combining all the separate PGN files into one, I used the utility that comes with SCID to convert it into the SCID database format. Along with the output of that utility is a file -.err format- of errors -if any- that occurred during conversion. While the number of errors I got is not much, it is large enough for it be a complicated process if I went through and deleted the games by hand.

An example from the first three lines of the error file (1 game):

```
my_games.pgn:(game 383, line 10658) Error: Invalid FEN: rnqkrbbn/pppppppp/8/8/8/8/PPPPPPPP/RNQKRBBN w EAea - 0 1

my_games.pgn:(game 383, line 10658) Error reading tag: [FEN "rnqkrbbn/pppppppp/8/8/8/8/PPPPPPPP/RNQKRBBN w EAea - 0 1"]

my_games.pgn:(game 383, line 10663) Error reading move in game graffitivisuals - walidmujahid, 2012: Ng3

```

Is there a utility out there where I could simply pass my PGN file though it and specify the game number -multiple- to delete. I am still new to SCID, so perhaps did I miss the fact that SCID has something that can help with this matter?

Any guidance on this would be most appreciated.

Post Script: GitHub was among the places that searched for such a utility, though, without fruition. If, perhaps, there is a script that comes remotely close to doing what I described, or perhaps even does exactly what I need, any guidance towards that script would also be most appreciated.

# Answer
A PGN file is simply a flat text file, which can be created/edited using a text editor (I use Notepad++).

> **ANSWER:** While using a text editor may not be optimal, or may not be an automagical way of many specific games from a large PGN file, it works. I don't know of a text editor specifically designed to deal with PGN files otherwise. Also, SCID itself allows you to delete games from a collection. Notice in this link the option to delete current game?

I would also observe that the FEN you've posted is only valid if you're playing Fischer (or 'random') Chess where the pieces are randomly placed at the beginning. Copy your FEN HERE and observe that while valid FEN, is not a valid opening position for a regular game.

The problem with your file is that it is mixing regular and Fischer chess games..
> 0 votes

# Answer
Maybe use the free Chessbase Reader and import/open the file. That might work.
> 0 votes

# Answer
For the specific requirement to filter out Chess960 games from a PGN file, you could use pgn-extract.pgn-extract home page Since such games necessarily include a SetUp tag, the --nosetup argument of pgn-extract allows them to be filtered out. The same argument could be used to remove any game that has a non-standard starting position.

Disclosure: I am the author of pgn-extract.
> 0 votes

---
Tags: pgn, scid
---


# Question
Title: KID fiancetto variation - reason for c6 after Nd7
I've noticed that when black goes Nd7 in the KID fiancetto variation, then often he follows up with c6. What is the main reason(s) for this? Especially, I'm asking this question as often the d6 pawn afterwards becomes subject for attack by white. First I thought the reason was mainly defensive to hold white knights away from b5 and maybe even d5, but I don't really see this being such a threat. Then I figured the reason for c6 was do go d5 at some point, but rarely does black indeed play this move, so I'm unsure as to why black usually does go c6 and thus creates this target on d6.

```
[FEN ""]
[Event "?"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.Nf3 O-O 5.g3 d6 6.Bg2 Nbd7 7.O-O e5 8.e4 c6 ( 8...Re8 9.h3 c6)

```

# Answer
> 3 votes
First of all, to sit back and wait isn't a good strategy for black, as white has many useful moves to make: `h3`, `Be3`, `Qc2`, `Rfe1`, `Rad1`. If white can get these moves in with black doing nothing, white will be clearly better.

So black has to look for counterplay. Most of black's options involve `c6` to activate the queen on the `d8`-`a5` diagonal. If you absolutely don't want to move the `c`-pawn, then one of the few options left is to play `exd4` followed by `Nc5` and `a5`. This is playable, but not popular, as white can place an annoying knight on `b5`, see Giorgiev vs Ilincic, Belgrade 2000.

Black can also try to play `exd4` and `Nc5` without `a5` (instead `Bd7`, `a6`, and so on). The game then can get sharp, but current theory says white is comfortable.

In summary: Black plays `c6` to get needed counterplay. The other options to get counterplay aren't quite as attractive.

# Answer
> 2 votes
> I'm unsure as to why black usually does go c6 and thus creates this target on d6.

The key point is this: it's not a weak point unless it can be attacked, and white can currently only attack it with one bishop, which is easily defended against. If white tries to attack it further, they can only do so by opening the d-file, which ends up removing the weakness (9. dxe5 dxe5, for example) and also demonstrates the usefulness of 8...c6 (it is covering d5).

As for why black is playing c6 over other options: the position in the centre is in considerable flux, and black doesn't know where they want the rest of their pieces until the centre settles (e.g. if white closes with 9.d5, the rook doesn't want to be on e8 and instead was perfectly fine on f8). 8...c6 is a move that retains black's flexibility and gives white another chance to act decisively. As previously mentioned, it is very useful if the centre opens with 9.dxe5, but it is also useful if white advances 9.d5, because after 9...c5 white can't take en passant and black gets a structure similar to the Czech-Benoni but with more comfortable development.

Of course, white is free to maintain the tension, continuing the theme of the fianchetto response to the KID.

Edit: in the exd5 exd5 lines, you are possibly wondering about the vulnerablity of d6, with the pawn defending it having advanced to c6. This is an important thing to think about, and I can't answer it from my own experience, but in practice the g7 bishop retreating to f8 is enough to cover it (swapping off the the bad bishop in the process :-) )

# Answer
> 0 votes
The purpose of c6 move is below .

* c6 stops the Knight on c3 coming onto d5.
* It makes a square for the Queen to come on c7 or sometimes gauge an eye over the Q-side . Q comes to a5 and then attacks b4.
* It eventually sometimes supports b5 which makes a Q-side pawn push.

---
Tags: kings-indian, fianchetto
---


# Question
Title: What are the laws concerning copyright of chess games?
Here is my specific situation: I have written a novel in which two characters play a game, the moves of which follow exactly a known game between two ranked players in ChessGames.com. Must I get permission from the two real players? Or must I only credit them in the acknowledgments of the novel? Or need I even do that? Any information, especially with legal citations, would be greatly appreciated!

# Answer
Chess games without annotation can't be possibly copyrighted. You don't need to inform them. You don't need to acknowledge them.

I've been using Carlsen's games (without annotation) for commercial. I literally sell his moves and the games. So far, the world champion has not complained.

Game annotations are protected by the laws. Make sure you only use the game moves.

@itub has some links, such as:

https://chess24.com/en/read/news/us-judge-agrees-with-chess24-on-chess-moves
> 6 votes

# Answer
There was a case last year where World Chess Championship sued chess24.com, who was publishing the moves of the games, and my understanding is that the conclusion was that chess moves are not copyrightable (disclaimer: I am not a lawyer!). You can surely find lots of information about this case by googling "world chess lawsuit", but here is a link telling the story in some detail from the defendant's point of view: https://chess24.com/en/read/news/us-judge-agrees-with-chess24-on-chess-moves

See also this article by a law professor: https://www.bloomberg.com/view/articles/2016-11-15/there-s-legal-intrigue-at-the-world-chess-match
> 5 votes

# Answer
A usual chess game (i.e., a competitive game between two players) is not copyrightable because there is no identifiable creator of that work (at least, this is the legal situation in Germany).

Annotations of all kind are copyrighted, problem compositions are copyrighted, a constructed game by a single author is copyrighted.
> 2 votes

# Answer
## They probably could be . . .

It is likely that a court would rule that a chess game is an act of authorship and thus could be copyrighted. But to do so, the players - or, more likely, the organizers of the event - would have to take some steps to publish or register the "work". And at some point they would have to take steps to defend the copyright from infringement. But copyrights are expensive to litigate and chess games have little commercial value, so it shouldn't be surprising that there aren't any court precedents (to my knowledge).

But there have been debates outside the courthouse and incidents where publishers refrained from stepping on an event organizer's toes to avoid trouble. Emmanuel Lasker apparently attempted to copyright some of his games - his reward was a press boycott. Eventually the chess community came to the consensus that any attempt to copyright games was bad for the game. For nearly a century the subject rarely came up. But in the last decade or so, there have been several events in which the organizers threatened litigation to prevent others from broadcasting game moves during the event. But I can't find any actual court cases or successful attempt to prevent publication of game scores after the fact.

## For the Good of the Game ....

So your ability to use these game moves is due to the fact that generations of players and publishers have worked under a general understanding that we all benefit from being able to publish game scores. As a member of the chess community, you have the moral responsibility to support the chess community and honor the players who have provided you with this gift. Legally, it is uncertain whether you need to attribute the moves to the players, and you take virtually no risk upon yourself if you don't, but if you have a drop of honor in your body, you will give a warm acknowledgement to them in a preface or end note.

## As for annotations and commentary . . .

That's a totally different subject, and most annotations may be copyrighted.
> 1 votes

# Answer
I don't think so, what advantage can you take from them? The tournament is the main area which they get benefits from, including ELO recognition. Besides, the important part of in a novel is not much the exact game but the *metaphor* you find in the game.

That makes it the idea made by you so if you work on the narrative it is your work. Focus on that and you would get the novel done.
> 1 votes

---
Tags: famous-players
---


# Question
Title: Is my solution to this puzzle wrong or a transposition of the official one?
I saw the following puzzle recently in a newspaper:

> ## Black to play and win
>
> ```
> 6rk/6qp/2Bp4/P1pP1p2/3bnP2/6BQ/7P/5R1K w - - 0 1
>
> ```

My proposed solution was

```
1. ...   Nf2+

```

and the lines I foresaw were

```
2. Bxf2  Bxf2
3. Rxf2  Qg1 mate

2. Bxf2  Bxf2
3. (something else)  Qg1+
4. Rxg1  Rxg1 mate

2. Rxf2  Bxf2
3. Bxf2  Qa1+ and interposing B or Q only delays the end

```

However, the given solution was

> ```
> 1. ...   Bf2!
> 2. Rxf2  ...
> ```
> (If `2. Bxf2? Nxf2+ 3. Rxf2 Qg1 mate`)
> ```
> 2. ...   Nxf2+
> 3. Bxf2  Qa1+ and white resigns
> ```

I can see three possibilities:

1. I missed something
2. My solution is as good as the official one
3. They're actually equivalent under transposition

Which is the case?

# Answer
> 4 votes
They're not *equivalent*, but your solution is just as good. In fact, it's more easy to find because Nf2+ is a 'forcing' move.

# Answer
> 2 votes
They aren't quite equivalent because of the differences in the position if White declines or partially declines the sacrifice (for example, after Nf2+ Rxf2 Bxf2, White doesn't have to retake the bishop - but after Bf2 Rxf2 Nf2+ declining the knight instantly loses the queen.) But both should win, even if Bf2 is slightly better.

---
Tags: analysis, puzzles
---


title: Can you save white from checkmate?

text:
# Question
Title: Can you save white from checkmate?
Is white able to recover/win this game after these moves?

And then black takes the bishop:

White resigned after this, what would you do?

# Answer
> 10 votes
First off: I suspect White resigned due to the material disadvantage rather than some immediate mating threat. Having said that, I don't see any reason not to give check on c8 and try to setup some threats here as White, since it seems like Black gets checkmated:

1.Qc8+, Ke7 2.Rb7+, Kf6 3.Qf5+, Kg7 4.Qxf7+, Kh6 5.Qg7#

# Answer
> 2 votes
Looking at the board I can speculate that both players are at almost beginner level. I do not see any reason why White should resign because Black does not have any forced checks. It is the middle game and both Black's knights are at the back rank, undeveloped. Any opening, you let knights get developed first within 5-7 moves. In fact this kind of position does not even need any concrete calculations because Black's queen alone cannot do anything. Here White should have attempted at least the checks shown in the above variation, and if he would have run out of checks, then I can understand the situation, else Black should resign here.

---
Tags: checkmate
---


title: When is a good time to double rooks?

text:
# Question
Title: When is a good time to double rooks?
When analysing my games with an engine (Stockfish 8) I found that I quite frequently miss when the engine thinks it would be a good idea/time to move a rook to the second rank to double up (I guess).

I had a short search on YouTube to find some material on the topic and couldn't find one at first glance.

Do you guys have any recommendations on how to recognise when the position allows/favours bringing rooks into position?

Maybe its a naive question but I'll give it a try anyway since I consider myself somewhat of an intermediate beginner.

# Answer
> 5 votes
You may consider doubling rooks if:

* There is an important open-file, and you want to make sure you have firm control on it. You want to minimize your opponent's controls to the file. (**very common**).
* There is a semi-open file with an isolated or backward pawn. The pawn is protected by your opponent's rook. You want to win it. (**very common**)
* If you want to exchange both rooks.
* If you want to improve the position of your rooks. In particular if no other good squares for the rooks to go.
* You have something to pin on the open-file, and you want to win it (look at the game below)

You may want to study the classical game between Alekhine and Nimzowitsch. Look at the final position:

> http://www.chessgames.com/perl/chessgame?gid=1012683&kpage=1

Here, you have absolutely no reason not to double your rooks for both sides. Nimzowitsch had to double to protect his c6 knight. Alekhine had to double his rooks to win the c6 knight. Note there is an open c-file and no any other good squares for the rooks.

# Answer
> 2 votes
There can be all kinds of reasons for moving a rook to the second rank.

* in order to double rooks (and/or queen) on an open or half-open file so that you control the file and can use it for access to the opponent's camp; This is a very common theme and often very strong.
* in order to protect a pawn on the second rank; e.g. in the King's Indian Main line (Mar del Plata variation) black often moves the rook from f8 to f7 where it protects c7, b7...
* in order to make space for another piece; in the same variation, after Rf7, black will often followup with Bf8 so that the bishop protects the d6 pawn
* in order to get to a better square; yet again in the same variation, after Rf7...Bf8 black can play Rg7 from where the rook supports a pawn push of g5-g4.

# Answer
> 0 votes
Doubling of the Rooks in Chess means that you want to capture an Open file . You do doubling because you feel that controlling any open file leads you to a better & faster attack . It exactly paves a Path for attacking your Opponent and keep the attack within your control. I would suggest you to go through some of the Games of Sicilian Dragon Yugoslav Attack where White clears the h-file sacrificing a Pawn and then tries to break open and checkmating Black's monarch . Simultaneously Black sometimes double his rook on c-file and goes for an exchange Sacrifice with Knight .

You can find one game of Nimzovitsch where doubling Rooks on f-file created the infamous Immortal Zugzwang Game . Immortal Zugzwang Game wiki Explanation

Immortal Zugzwang Game

---
Tags: rooks
---


# Question
Title: Bobby Fischer photos in his NY apartment?
Are there any photos of young Bobby Fischer in his NY apartment?

# Answer
> 3 votes
Here are two pictures of Bobby Fischer (Robert James Fischer), in a New York apartment, mainly taken from the movie (documentary) Bobby Fischer Against The World.(I have no rights to this pictures ,but I think I can post them in some networking sites).

---
Tags: fischer
---


# Question
Title: Programming three-fold repetition for my chess engine
I'm making a chess engine that has to implement a three-fold repetition as my AI vs AI engine repeats the same moves over and over again (Have a look at my post here - My chess AI makes the same repeated moves). I've read the rules of this scenario from the wiki and would like to implement it. I'm not sure if I have understood the rules thoroughly, so what I'm doing here is -

1. Checking if the present move made (from the movelog I have) has already occurred before.
2. If it did, check for one more occurrence (as we need three in total).
3. If the moves pattern for all the three re-occurred moves is same, return true.

Please have a look at my Java code and suggest me the corrections.

```
    boolean isThreeFoldRepetition() {
        List<Move> allMoves = Table.get().getMoveLog().getMoves();
        int currentMoveIndex = allMoves.size()-1;
        int secondFoldMoveIndex = currentMoveIndex - 4;
        int firstFoldMoveIndex = secondFoldMoveIndex - 4;
        int distance = currentMoveIndex - secondFoldMoveIndex - 1;

        while(firstFoldMoveIndex >= 0){
            Move thirdFoldMoveMade = allMoves.get(currentMoveIndex);
            Move secondFoldMoveMade = allMoves.get(secondFoldMoveIndex);
            Move firstFoldMoveMade = allMoves.get(firstFoldMoveIndex);

            if(thirdFoldMoveMade.equals(secondFoldMoveMade) &&
               secondFoldMoveMade.equals(firstFoldMoveMade) &&
               firstFoldMoveIndex - distance >= 0){
                int gap;
                for(gap = 1; gap <= distance; gap++){
                    thirdFoldMoveMade = allMoves.get(currentMoveIndex - gap);
                    secondFoldMoveMade = allMoves.get(secondFoldMoveIndex - gap);
                    firstFoldMoveMade = allMoves.get(firstFoldMoveIndex - gap);

                    if(!thirdFoldMoveMade.equals(secondFoldMoveMade) || !secondFoldMoveMade.equals(firstFoldMoveMade))
                        break;
                }
                if(gap == distance)
                    return true;
            }

            secondFoldMoveIndex -= 2;
            firstFoldMoveIndex = secondFoldMoveIndex - distance - 3;
        }
        return false;
    }

```

# Answer
Threefold-repetition is about **a position** (not moves) occurring three times. Those positions **do not** have to be reached by the same moves.

Also (as this also seems to be confused sometimes) it is completely irrelevant when this happens, e.g. you can have the same positions after moves 10, 42 and 63 and it would still be a draw.

You should check whether the position is repeated. So basically at every move you need to check whether the position occurred in the game before. By *position* I mean the same position of all pieces on the board *and* the same castling rights *and* the same player to move *and* the same enpassant rights. That is, basically you are checking whether the FEN are the same (except for halfmove clock and fullmove number).

Something like:

```
int positionCount=0;
while(iterate through game positions) {
    if ( positionToCheck.piecesPosition == iterationPosition.piecesPosition &&
         positionToCheck.castleRights == iterationPosition.castleRights &&
         positionToCheck.enPassantRights == iterationPosition.enPassantRights &&
         positionToCheck.playerToMove == iterationPosition.playerToMove ) {
      positionCount++;
    }
    if (positionCount==3) { return true; }
}
return false;

```

Of course you can simplify the above algorithm. E.g. you only need to iterate over position with the same player to move. Also you only need to iterate over positions back to the last pawn move, capture or castling move.
> 14 votes

# Answer
Although @user1583209 is on the right track. His approach would only work for a chess GUI but too **slow** for a chess engine. Modern engines only check for the last few moves, they won't go all the way back to the initial position because that'd be an almost waste of time.

You have complicated your code too much. In reality, checking for repetition is very simple:

> https://github.com/official-stockfish/Stockfish/blob/master/src/position.cpp

```
int cnt = 0;
for (int i = 4; i <= end; i += 2)
{
  stp = stp->previous->previous;

  // At root position ply is 1, so return a draw score if a position
  // repeats once earlier but after or at the root, or repeats twice
  // strictly before the root.
  if (   stp->key == st->key
      && ++cnt + (ply - i > 0) == 2)
      return true;
}

```

You go back in the history and check the key for your position. **Very simple**. You may want to ignore the `ply` check.

You should have a way to hash your position, if you don't you will need it for transposition table anyway.

A useful reference link to prove my idea is correct:

> http://talkchess.com/forum/viewtopic.php?t=59322&highlight=move+repetitions
> 6 votes

# Answer
I would look at the source code for TSCP which implements zobrist keys. Basically you assign a unique number to each position and store the numbers in a list. Then check if the same number is in the list three times. you generate the unique number based on the position of the pieces, en passant square, side to move. here i have copied and pasted the TSCP code (authored by Tom Kerrigan). hash\_piece is indexed by the color(2), piece type(6), and position(64). hash\_side is the side to move. hash\_ep is the en passant square. The initialization function populates a table of random numbers for each of these possible entries. To generate the unique position for a position
you look up all the entries correspoding to a given position and xor the numbers from the three tables (this is the set\_hash function). You probably dont need the hash\_rand on newer computers with better random number generators.

```
void init_hash()
    {
        int i, j, k;

        srand(0);
        for (i = 0; i < 2; ++i)
            for (j = 0; j < 6; ++j)
                for (k = 0; k < 64; ++k)
                    hash_piece[i][j][k] = hash_rand();
        hash_side = hash_rand();
        for (i = 0; i < 64; ++i)
            hash_ep[i] = hash_rand();
    }

    /* hash_rand() XORs some shifted random numbers together to make sure
       we have good coverage of all 32 bits. (rand() returns 16-bit numbers
       on some systems.) */

    int hash_rand()
    {
        int i;
        int r = 0;

        for (i = 0; i < 32; ++i)
            r ^= rand() << i;
        return r;
    }

    /* set_hash() uses the Zobrist method of generating a unique number (hash)
       for the current chess position. Of course, there are many more chess
       positions than there are 32 bit numbers, so the numbers generated are
       not really unique, but they're unique enough for our purposes (to detect
       repetitions of the position).
       The way it works is to XOR random numbers that correspond to features of
       the position, e.g., if there's a black knight on B8, hash is XORed with
       hash_piece[BLACK][KNIGHT][B8]. All of the pieces are XORed together,
       hash_side is XORed if it's black's move, and the en passant square is
       XORed if there is one. (A chess technicality is that one position can't
       be a repetition of another if the en passant state is different.) */

    void set_hash()
    {
        int i;

        hash = 0;
        for (i = 0; i < 64; ++i)
            if (color[i] != EMPTY)
                hash ^= hash_piece[color[i]][piece[i]][i];
        if (side == DARK)
            hash ^= hash_side;
        if (ep != -1)
            hash ^= hash_ep[ep];
    }

```
> 2 votes

# Answer
Why not just keep a map indexed by the position hash pointing to a count of how many times it has been seen so far? No iteration required... just update the hash as you traverse the move tree.
> 0 votes

---
Tags: engines, programming, threefold-repetition
---


# Question
Title: Is today's chess.com daily puzzle a draw (as hinted at in the puzzle title)?
Today's daily puzzle on chess.com is called Desperation Draw:

**White to move**

```
[FEN "r5k1/P4ppp/8/8/p1p1P3/4KP2/2P3PP/5R2 w - - 0 1"]

1. Rb1 Rf8 2. Rb8  *

```

One of the commentators asked:

> What draw?

I agree with this. I think this is a simple win for white who threatens to promote soon when black has no counter play, e.g. 2...a3 3. Rxf8+ Kxf8 4. a8Q+ Ke7 5. Qxa3.

My question is, **am I missing the draw in the position above?**

# Answer
> 3 votes
No, you are not.

It's an easy win for white as far as I can see.

---
Tags: analysis, draw, puzzles
---


# Question
Title: Chess software to evaluate move and give marks
Well, I am new here and I am not quite sure whether this question is appropriate here. In case it is inappropriate, please tell me the correct site for it.Well, my question is :

I want a chess software in which I can play against chess engines or players and also **I want the software to evaluate each move and give me marks accordingly and instantaneously.** (Note : I have already tried Ubisoft's Chessmaster but I want a software that will evaluate how much percent I am correct not just whether my move is the best move or not.)Can anyone please name any such software. I am ready to buy it in case it is not free-ware. Lots of thanks in advance.

# Answer
> I want a software that will evaluate how much percent I am correct not just whether my move is the best move or not.

Chess engines do not usually evaluate moves as percentages (and I'm not even sure how that would work tbh), but by evaluating the position in terms of a normative standard (like the material value of 1 pawn, with +1 meaning white is up by 1 pawn, and -1 meaning that black is up by one pawn) assuming *optimal* play.

Simply put: every position has an evaluation based on positional and material considerations (which is engine dependent, hence why different engines would often assign different evaluations to the same position). Every move you make causes a transition between two distinct positions, and the quality of your move is the difference of this evaluation from the *before* to *after* position.

If the engine got the evaluation right, the optimal move has value 0. **The value is 0 because the engine believes that this is the optimal move, and assigned the evaluation based on *that* move**. From white's perspective, a sub-optimal move would have a value of \< 0. A value of -0.3, for example, would typically mean that the position after the move was made is now 1/3 pawn worse than before.

Almost every chess engine I've come across can show you the difference in evaluation between two positions, or it is at least easy to calculate (if the evaluation went from 1.2 to 0.7 after white's move, then the move quality was -0.5, or half the value of a pawn, which is typically considered a reasonably big blunder). **Shredder** and **DroidFish** (which is free and available on Android) are examples of chess apps that provide this feature, but there are many others on pretty much every conceivable platform.
> 4 votes

# Answer
If you want to know the quality of every move and a estimated ELO strength for each player you can use the Android app called "Analyze your games". It uses Stockfish internally to compare your moves with the best ones.
> 4 votes

# Answer
The app "Analyze your games" is free (no adds) and you can find it here:

https://play.google.com/store/apps/details?id=com.bento.analyzeyourgames
> 3 votes

# Answer
If you leave an engine running, and step through a game, you can see what happens to the evaluation. The Fritz interface flashes a red signal light when one side has made a mistake. Most GUI's allow you to run an engine in Infinite Analysis or Kibitzer mode, eg. Arena, SCID, Winboard, etc.

There have been a few programs that generate move by move engine numbers for full games for Windows: Gerd Hübner's ChessAnalyse and Jack Welbourne's Chess Game Report.

I wasn't able to get Analyze Your Games to work on my Samsung Galaxy phone. The board was unresponsive to touch, and it just gave me an error message when I imported pgn from Chess PGN Master Pro or Droidfish.

A lot of programs have a full game analysis feature where they attach question marks to bad moves, and suggest alternatives, eg. Fritz, Hiarcs Chess Explorer, Shredder, Aquarium, Arena, SCID.
> 2 votes

# Answer
I understand what are you thinking at this point. Even I would also like to have software which would tell me the move is between two category levels. Let's say, software which says after you play a move that this move is a

1. A Super GM Level move. above 2700 Elo
2. A GM/IM level move. above 2500 and \< 2700.
3. A Master Level move. 2200-2400
4. 2000-2199
5. Amateur Level below 2000
6. An Experienced level 1600-1800

and continue till the beginner level.

It would be a nice way of learning, but unfortunately it is yet to come out.

The only thing which you can make out is feed your game to StockFish / Fritz and see after every move you make, the score of the game changes. Since computer engines also calculate depending upon depth and do a lot of calculations, you can see, according to the score, who is better at any point. If you are playing White and the score is always \> +0.0 and gradually rises, then you can be sure that you did not make any mistake.

You will also see a lot of lines that the computer suggests, and if most of your moves match, then definitely, you have played very well .

But please note one thing, there are some positions which Computers are not able to analyse, so do not get biased completely by the system. Instead a Coach's recommendation is more useful. Computers always give you a negative score when playing gambits.
> 1 votes

# Answer
I'm pretty sure ChessBase does everything you want (and a lot more). It can analyse games in real time and much deeper if you leave it running. It also has the option to give better alternative moves.

I use an older version so I'm not sure of the latest prices and capabilities but I'd definitely look it up.
> 0 votes

---
Tags: software
---


# Question
Title: How could I have extracted an opening advantage in this Owen's defence game?
I played as white against Owen's defence from black, which is seen as being quite dubious. After 21 moves, we agreed to a draw.

My question is, **how could white have extracted an opening edge here?**

```
[FEN ""]

1. d4 e6 2. e4 {2. c4 is also played in the Horwitz defence, but I wanted to aim for the French, as I used to play it as black} b6 3. Nf3 Bb7 4. Bd3 Nf6 5. Qe2 Bb4+ 6. c3 Be7 7. O-O h6 {This was the first move that surprised me, so I chose 8. Nbd2 and 9. Re2 simply because they were thematic, as I couldn't see a way to punish 7...h6} 8. Nbd2 d6 9. Re1 Nbd7 10. e5 {I'm not too sure about this move, but my plan was to make a few trades to play Nd2-f3 to liberate the dark square bishop. I also thought the open d-file could be useful} dxe5 11. Nxe5 Nxe5 12. dxe5 Nd5 13. Be4 c6 14. Nf3 a5 15. Rd1 Qc7 16. c4 Nb4 17. a3 Na6 18. Be3 c5 19. Bxb7 Qxb7 20. Rd3 O-O 21. Rad1  1/2-1/2

```

# Answer
> 4 votes
Black's opening play doesn't look good. This is more passive and dubious than a normal Owen's.

The suggestion of `10. Nf1` followed by `11. Ng3` is a good one and should give white a nice advantage.

But I believe black should be punished harder for their passive play. Perhaps `8. e5 Nd5 9. a3!?`.

```
[FEN ""]
[StartPly "17"]

1. d4 e6 2. e4 b6 3. Nf3 Bb7 4. Bd3 Nf6 5. Qe2 Bb4+ 6. c3 Be7 7. O-O h6 8. e5 Nd5 9. a3!?

```

Black has to worry about the knight on `d5` getting trapped. After `9... c5 10. c4 Nc7 11. dxc5 bxc5 12. Nc3`, white obtains a better position than they usually get in Owen's.

```
[FEN ""]
[StartPly "23"]

1. d4 e6 2. e4 b6 3. Nf3 Bb7 4. Bd3 Nf6 5. Qe2 Bb4+ 6. c3 Be7 7. O-O h6 8. e5 Nd5 9. a3!? c5 10. c4 Nc7 11. dxc5 bxc5 12. Nc3

```

Black's kingside looks really weak.

# Answer
> 3 votes
I really don't like 10. e5 which makes black's bishop on b7 strong, gives black an outpost for his knight on d5 and makes you lose control of the center. There is no need to force anything in the center. Instead of 10. e5 I'd consider regrouping your pieces, e.g. the knight from d2 could go via f1 to g3. Or you could try to create some weaknesses on the queenside by playing a4-a5. Or you could prepare a kingside attack playing h3 (which is useful even without kingside attack).

# Answer
> 2 votes
I do not believe that you should have agreed to a Draw after move 21)Rad1 since this is too early . If you compare the position of the Pieces White's pieces are ready for a K-side onslaught . The pawn is on e5 . I remember the great Alexander Alekhine stated that " When the pawn is on e5 White should attempt a K-side attack " . The Black Queen is somewhat misplaced and cannot come immediately to K-side for any rescue . Black has little to do on Q-side . From White Bf4,Nd2-\>Ne4 and then sac on f6 and then swinging Rook on g3 and Queen on h5 will definitely tie Black down . The Paws g4 h4 are also a part of White's arsenal .

One more thing : 10)e5 is just too early here . You could have delayed e5 for a moment and maneuvered Nf1 -\> Ng3 .

# Answer
> 1 votes
Getting a substantial advantage in the opening against this type of system is very difficult in general, since Black's position is designed to cope with various direct attacking attempts from White. So the best course of action I'd reckon is to try and get a space advantage, and optimize your own piece placement. This is easier to accomplish, since Black isn't really trying to challenge White at all in the opening.

Consequently, I agree with user1583209 about the move 10.e5. This move is trying to clarify the situation in the centre by force, which is not in line with the approach of building up your position. You don't have to prove your advantage as White in the position after move 9; it's Black who has to prove equality!

# Answer
> 1 votes
If it seems like I've pointed out a lot here, well...this sort of thing is a problem for me too, knowing I have a space and development advantage I should be able to cash in but I don't. So I ran this through Fritz to see improvements. And you may like to do so, too. Sometimes it's frustrating to see a move that looks good but you don't quite have the guts/justification to play it.

Fritz gives 8. e5 Nd5 9. a3. It's always tough to know when to push the pawn, and while 8. Nbd2 looks natural, the Black knight is a target for the pawns, especially with the pawn on b6. It can't go to b5. So Black has to play ...Bg5 or ...g5 to protect it, each of which is ugly. ...c5 is a possibility, but dxc5 and Rd1 give you the open file.

With 8. Nbd2, an e5/a3 thrust leaves you open to Nf4. The thing is that while developing moves are good, the knight might be better placed on c3, and a3/c4 might gain space and give you that square. Also, if you are worried c3-c4 is wasting a move, remember that's not really the case. ...Bb4+ c3 Be7 provoked it.

11. Nxe5 also seems to relieve the pressure on Black. As a general principle you shouldn't exchange pieces when you have a space advantage unless you get something in return. But you still have an edge. Another poster noted the Bb7 could gain scope, but with a knight or bishop on e4, you are more likely to block it.
12. ... c6 is also weak. It blocks the bishop, and c4! is vigorous. ...Nc7 is awkward, but ...Nf4 14. Qf3! loses a pawn. ...Nb4 15. a3 Na6 16. Qg4 and Black must play ...g5 or ...g6 with kingside pawn problems. White will again get the d-file. You played c4/a3 in the game, but letting Black get ...a5 in meant you found it tougher to play b4 and restrict Black's pieces on both sides of the board.

Finally, this is something I had to throw into an engine, but Rd3, while it doubles the rooks, also lets Black exchange them off. Fritz's idea of Nd2 followed by Qg4 and Ne4 looks strong. The point is that Black is too busy defeinding a kingside attack to swap rooks right away.

18. Bf4 also seems more accurate than Be3. It allows for an attack with Bc2 and Qd3 or e4. Black's having played ...h6 makes for a potentially weak kingside.

It looks like you considered the moves that a computer engine marked off as the best, and in some cases you played them a bit too late, and in some, a bit too soon. When you have more space it's tough to know when to squeeze and when to use tactics. Often you don't need to "just" develop with a space advantage. It may be better to restrict your opponent from meaningful development, for instance, with the early 8. e5. It's good to check for overextending, but Black's development isn't good enough to poke at any of your weaknesses.

The main problem for White is to figure how to take advantage of space and make Black's pieces stumble over each other. The Bb7 is rather good, but once Black plays ...c6 or ...c5 there are is that weakness on d6, and e4 is always available for a bishop or knight.

---
Tags: opening, analysis, french-defense, owens-defence
---


title: How to solve mate-in-N problems

text:
# Question
Title: How to solve mate-in-N problems
Here is a mate-in-4 I have been trying to solve:

```
[FEN "2r4r/b5pp/q3pp2/8/4QBk1/8/3R1PPK/4R3 w - - 0 1"]

```

(white mates in 4). I have been looking at it for about half an hour but not solved it. My question is: **what can I do to improve my ability to solve problems like this**?

(please don't just give the solution, I can easily find that by computer, but you can't use computers in a game).

---

Here is what I have tried so far.

Enumerating attacks and checks.

* White checks: Qf5+, Qg6+, Qf3+, Qxe6+, B-anywhere+, f3+
* White captures: Qxh7
* Black checks: none
* Black captures: Bxf2

Enumerating other ideas:

* Black can play Bxf2 or Qf1 which will cause havoc for a move , so probably the solution is checks on every move; at least the first two
* White has to be careful not to let BK run to g6 as then it can move to f7 escaping mate in 4
* In several variations below, Kh5 escapes with ...g5 or other pawn cover, so I am looking for tricks involving sacrificing rook to break that pawn cover.

Tree of analysis (have omitted some sub-variations that mate for brevity)

```
Be3+ Kh5; Rd5+ g5; ???
Bc7+ (or other B moves) Kh5; Rd5+ g5; ????
                             g4+ Kh4; ????
Qf3+ Kf5; Qh5+ (otherwise Kg6) g5; g4+ Kxf4; ????
Qf5+ or Qg6+ or Qxh7 don't go anywhere
Qe6+ Kxf4; Re4+ Kg5; Rg4+ Kh6; ????
f3+ Kh5; g4+ Kh4; ????
    Rd5+ g5; g4+ Kh6; ????

Rd3 Qxd3; Qxd3 Kxf4; no mate
Re3 Bxe3; Bxe3 can't be better than 1.Be3
Rd5 exd5 Be3+: doesnt work
g3: doesn't seem to do anything, Black can wait

```

Now I have looked at all the checks and some other interesting moves, none of them work, and so to solve the problem online I'd be reduced to just guessing random moves (and then probably being stumped on the resulting mate-in-3 for a while, as if I could solve that easily then I would have realized the first move by now).

But in a real game that is not possible; so where do I go from here?

Is there always a "key idea" to look for (and if so, how do I look) or sometimes do you just have to be able to brute force every possible move no matter how unlikely? I can't even think of any more candidates I haven't checked.

# Answer
> 5 votes
Assuming this is a chess *problem*, then you want to start by looking at things that show up as problem themes, more than as game themes. There are a few salient features of the position:

* White's queen-bishop battery; it seems very likely that discovered checks from the bishop are likely to be a mating resource.
* The white bishop being on a line with the king, thus leaving it vulnerable to a pin from either the Ba7 or the Qa6.
* The open h-file, and in particular the possibility of a king-rook battery to deliver mate.
* More remotely, the possibilities for interference between the black pieces (e.g., bishop/rook interference on c5).

Given these, I would investigate the possibility of a move like Rh1; this offers up the threat of 2. Be3+ Kh5 3. Kg1 mate and forces black to defend immediately. The most natural defenses are via the aforementioned pinning moves, 1...Bb8 and 1...Qd6, so I'd start looking there.

--

Assuming, OTOH, that the problem is a tactics puzzle more than a 'chess problem' problem, then I'll just point out that your analysis missed one particular bishop check, and you should consider the question of where the bishop can go that covers key squares in the vicinity of the king; not just for a mating net, but also as possible 'drop points' for the queen.

# Answer
> 4 votes
The other two answers give you a several good hints to solve the problem in your question, so I won't deal with that specifically. As for the heart of your question **"What can I do to improve my ability to solve problems like this?"**, I might be able to offer a little help.

The first thing to note is that there is no way to really improve *except* to continue solving mate problems. The important thing here is that you will both learn (and continually improve on) a process that you can use to solve any position that you believe might contain a mate somewhere, and more importantly that you will be repeatedly exposed to different tactical and mating 'patterns' within each problem.

A good way of doing this is to work iteratively from the shorter puzzles to larger ones. Some people like to take pride in being able to solve puzzles with a large number of moves, but restrict themselves to the simpler varieties so as to avoid damaging their ego. In reality, there are many problems that are mates in 2 or 3 that can take a decent amount of concentration to properly solve, so there's no shame in looking at the shorter ones.

As a resource for doing this I recommend a book similar to Laszlo Polgár's *Chess: 5334 Problems, Combinations and Games* (ISBN 1579125549), which begins with several hundred Mate-in-1 puzzles before ramping up to mates in 2 and 3. The here is that you get a reasonable grounding in all of the basic patterns that occur in one-move mates, then two, three and so on. Even just solving the first section of this can benefit if you haven't done any serious training in this area before.

This is not exactly the sexiest way of improving your vision, as it does require some work, but it is also less demanding than it sounds, and should be something that sticks with you throughout your playing career.

# Answer
> 3 votes
I start off by looking at the king positions. White's King is well protected; Black's is not. Notice all the spots the Black K cannot go. Aim to take away all the safe spots.

If we chase the Black K around, what's the worst that can happen? That it escapes through the hole on `f7`. Preventing this is the entire point of the problem. The White Q is blocking that hole so I would not be inclined to move it. Then I looked at various discovered checks with the B. I saw `Bh6+` but didn't see a lot more after that.

Then I noticed the Black K is in danger from the White pawns. So what happens if we let the pawns do the heavy lifting? Try that.

The Black Q and B shut down the White Rooks by controlling `d3`, `d4`, `e2`, and `e3`. How can we bring some heavy wood into the game? It would probably be helpful if we we able to place a R on `d4`, `e4`, or `e5`.

So, without giving the solution, that's my initial approach.

# Answer
> 1 votes
Basically it is "trial and error"!

Chess is all about analysis, and doing it in a proper way! That means not wasting time with things that go no where! This is the main difference between beginner and master level.

Especially for mate tactics what can help you to find your way through is to be acquainted with the most common mate patterns, which are pretty much clear in Mate in 1 or 2 positions, but not that much in Mate in 3 and 4 where the mate pattern needs to be built for the mate to happen. It could mean removing a defender, or reducing the scape area for the king placing a piece in a better position, etc... until you can apply the mate!

For your problem try to see what happens after Rh1... =\]\]

Here are some of the most common mate patterns. So what would be the mate pattern for your problem?

The more chess pattern positions, not only mates but also pins, fork, interference, etc... you have, the more quickly you will make good analysis of positions. You can achieve this by solving tactics in a daily manner. The habit to solve a minimum of 20 tactics a day has helped me to improve a lot in my chess lately.

I hope this might be of some help!

# Answer
> 0 votes
I think when you are looking for a mate, the answer lies in blocking out the escape route of opponent's King, in this case Kg6 is clearly something that white does not want. And since white Queen is the only piece that can guard that square you must look at other pieces for a tactical mate. Clearly the second thing then is trapping black King on h-file, which can only be done with white moving Rh1, which essentially are three moves: moving the pawn because you want to then move your king away from h-file and moving the rook. And since its a mate in four, the fourth move will definitely be a check.

---
Tags: learning, tactics
---


# Question
Title: Does an out of turn draw offer constitute an actionable distraction / time penalty?
I was playing in a sudden death time control last night with less than 5 seconds left and while thinking about my moves with literally 2 or 3 seconds remaining, my opponent blurted out a draw offer. Startled by this, I blundered and lost the game.

My understanding is that draw offers must be made when the OFFERER's clock is running and that offering a draw or making other statements to an opponent when they are thinking is a distraction and is not allowed.

Would I have been within my rights to stop the clock and demand from the TD that 2 minutes be added to my clock because of the distraction?

The game was played under USCF rules and was in sudden death with seconds remaining for both players.

# Answer
> 6 votes
According to my copy of *US Chess Federation's Official Rules of Chess (5th Edition)*, rule 14B2 states:

> If a player offers a draw while the opponent's clock is running, the opponent may accept or reject the offer. A player who offers a draw in this manner may be warned or penalized for annoying the opponent (20G).

Note that it says "may", not "must". Rule 20G says that the director has discretion to say whether there was a violation and what the penalty, if any, should be. So you could request, but you could not "demand", that the time be added.

Rule 1C2a says that two minutes added to your clock is the standard penalty if one is imposed. 1C2b, however, explicitly states that the director can vary from this.

Rule 21F says you indeed have the right to stop the clock to ask for a ruling from the director. And you must do it right away; you ordinarily waive your rights if you don't notify the director promptly.

# Answer
> 5 votes
I don't know about USCF rules, but according to FIDE Laws of Chess, article 9.1.b.1:

> A player wishing to offer a draw shall do so after having made a move on the chessboard and before pressing his clock. An offer at any other time during play is still valid but Article 11.5 must be considered.

Where article 11.5 is about distracting the opponent and says:

> It is forbidden to distract or annoy the opponent in any manner whatsoever. This includes unreasonable claims, unreasonable offers of a draw or the introduction of a source of noise into the playing area.

So, according to my understanding, offering a draw when the opponent's clock is running is not forbidden unless it is "unreasonable" (e.g. you offer a draw in lost position) or you offer a draw every other move or so, etc.

---
Tags: rules, time-control, uscf
---


title: Delay clock with delay not set

text:
# Question
Title: Delay clock with delay not set
Over the past few years of tournament play, I've seen three games where the delay was not enabled on a digital clock. In all of these cases, the clock was a Chronos set to display HH:MM until the last 10 minutes, when it would change to MM:SS.

In one game without the delay, I was playing white in a G/105 tournament. I ran my time down from ~12 minutes to ~6 minutes, and my opponent had ~9 minutes. On my next move, I noticed that the clock started right away and pointed it out to my opponent (we are actually the two TD's for the club, so we didn't really have anyone else to make the decision). We agreed to turn on the delay at that point.

Now according to a strict interpretation of the rules, we're stuck without the delay because that's how we started the game. I usually make sure that the delay is set in the first few moves, but I just didn't notice that the clock moved right from 105 to 104 when he started it at the beginning of the game instead of waiting 5 seconds. So after that, the only time I could discover the oversight was when we got below 10 minutes.

Is there a reasonable way to deal with this? Am I just out of luck if my opponent tries to pull a fast one in the future? Theoretically he could be penalized for unsportsmanlike behavior, but that seems extreme if it really was just an honest mistake.

# Answer
There is an article by Geurt Gijssen on Chess Cafe (4th question asked) that touches on the event that the clock's initial time control being incorrectly configured, but only noticed much later in the game.

He quotes the FIDE rules:

> The Laws of Chess cannot cover all possible situations that may arise during a game, nor can they regulate all administrative questions. Where cases are not precisely regulated by an Article of the Laws, it should be possible to reach a correct decision by studying analogous situations, which are discussed in the Laws. The Laws assume that arbiters have the necessary competence, sound judgement and absolute objectivity. Too detailed a rule might deprive the arbiter of his freedom of judgement and thus prevent him from finding the solution to a problem dictated by fairness, logic and special factors.

Geurt responds:

> I especially like the last part of the last sentence: a solution should be “dictated by fairness, logic and special factors.” With this in mind, I think it is quite unfair to change the time modus at the moment a player only has one second on his clock in such a way that he only has this one second left. Therefore, I see two possible solutions: Change the time mode after the first period; Change the time mode at the moment of the claim, but the player should be given a reasonable amount of time (at least one minute) for the remaining moves. I prefer the second option.

In your situation, it sounds like a reasonable action to stop the clock and set the delay correctly. As for other cases, it looks like it lies to the TD to determine a fair trade-off.
> 13 votes

# Answer
According to the 5th edition of the USCF rules (rules 16O and 16P), the TD should use his discretion if a clock was erroneously set. It gives the guidance that if any time is subtracted from a clock, it should leave the player with at least 5 minutes, or one minute per move until the time control, whichever is greater (although this doesn't seem to apply in your case since you were adding a delay, not subtracting time.)

If it was intentional, the "TD Tip" by this rule says to add two minutes the the injured player's unused time after making any other corrections (which seems like a very minor penalty in such a situation, but I didn't write these rules, I'm just reading them.)

Your solution of simply turning the delay on seems reasonable. After doing that, you both then had exactly the amount of time left that you thought you had, which is 6-9 minutes with a 5 second delay. Assuming that you were at no point blitzing moves, you also could have considered adding time to both clocks of (5 seconds * number of moves), to get back the time you should have had, but that might be awkward.
> 0 votes

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Tags: rules, uscf, chess-clocks, tournament-directors
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title: How are the scores decided in Chess?

text:
# Question
Title: How are the scores decided in Chess?
Consider the following pictures:

I would like to understand the following:

* My understanding is that it depends on the opponent's move against our move. Am I right?
* What is the minimum and maximum range of the score?
* When one can achieve the maximum score at very first move?
* What is the use of the score?

(Sorry for asking very basic questions. Newbie for the Chess stuff).

# Answer
Those aren't scores; there are just three possible scores in chess: White wins, Black wins, and draw.

Those are *evaluations* of the chess engine; a score of +0.62 means the engine thinks White's position is better by 0.62 pawns. A negative score would mean Black is better. On professional level, a score of 1.5 pawns is in most positions decisive, i.e. enough to win the game. However, weak moves by the players will change the evaluation.

The maximum and minimum score depends on the chess engine you're using. If you play the game till checkmate, you will see that the scores will get larger (either more positive or more negative) until you see something like `+#8` which means White can mate in 8 moves.
> 18 votes

# Answer
As pointed out by Glorfindel, these are *evaluations*, which tell you who the engine thinks is better. A positive score means white is better, a negative black is better and values around zero mean that both sides are equal. These evaluation values are (traditionally) displayed with two decimals which is much too high precision for humans. In practical play you would hardly notice a change of +-0.1 or so.

Take these values with a grain of salt, particularly for any evaluation between -1 and 1: there are many cases where the engine evaluations are not good, such as openings or closed positions with lots of maneuvering. Ignore the evaluation in these cases. On the other hand, in very tactical positions you can usually trust engine evaluations. Starting from values above around 1.5 (or below -1.5) in many positions the game ends decisive with a win for white (black) assuming perfect play.

The actual evaluation is calculated based on many factors. The main one is material, and this is also how the evaluation is normalized, namely such that a value of 1 corresponds to one pawn. Similarly other pieces have values of around 3 (bishop, knight), 5 (rook) and 9 (queen). Other factors include piece activity, king safety, control of the center, etc.

With regard to your questions:

> What is the minimum and maximum range of the score?

In typical games you will find a maximum of maybe around 20 (or minimum of -20). Beyond that the engine can usually count down to mate and would display the number of moves to mate. If you wish you can probably construct a very closed position (e.g. all pawns blocking each other) and give one player a huge material advantage and in that case you might be able to reach very large evaluation values where the mate is beyond the calculation power ("horizon") of the engine.

> When one can achieve the maximum score at very first move?

There is no meaningful answer to this. If there is a first move which gives you maximum score this will depend on the details of the engine and the calculation depth more than on anything else. Another engine might very well give you another best first move. Engines are not powerful enough (or chess is too complex) to give you a good answer to this. That's why engines use opening books and do not calculate anything at the start of the game. Experience has shown that all normal moves (1. e4,d4,c4, Nf3...) give white a small advantage but nothing more.

> What is the use of the score?

For the engine, it decides what move to play based on this score. Very simplified you could say that the engine calculates all possible lines down to a certain number of moves and evaluates the final positions using this score. It then picks the line which gives it the best score in the final position.

For a human, you can use this score to analyze your own games or to analyze openings/endgames/... in order to find the correct moves or to locate blunders.
> 8 votes

# Answer
Ok,

Going by your Questions I paste below and answer accordingly .

> What is the use of the score?

The use is to determine whether you have an advantage or you are better playing or winning. For best results take a good game and analyse with Fritz/StockFish. You would see that as the game progresses there will be a shift as whoever plays well.

> My understanding is that it depends on the opponent's move against our move. Am I right?

Almost true but not absolutely. The Score is a mathematical evaluation like for example during the start of the Game it is `0.0`. It means both are equal at this point. The Score depends upon a number of factors like more space, pieces, king safety and a lot more.

> What is the minimum and maximum range of the score?

The Score is always in favor of Black or White. You can see that when it has a winning combination it can be -infinity to +infinity. The higher the score it means it favors a particular side.

> When one can achieve the maximum score at very first move?

It does not depend on you except you are playing your opponent at the beginner level and scholar's mate or fool's mate is played on board.
> 2 votes

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Tags: learning, beginner, evaluation
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# Question
Title: Analysing Positions in Databases with a program
I've got two questions. I'm wondering if:

1. It is possible to search for certain positions in a database (like Chessbase) and display all of them in a text file.
2. To be able to assign a score to each position automatically with a chess engine.

I've got some notions of programming but I wouldn't mind getting some ideas on how to write such a program.

# Answer
1. Use pgn-extract:

> ... FEN positional matches with -t ...

2. Use ChessArtist. It supports any UCI chess engine, including Stockfish and Komodo.
> 1 votes

# Answer
I am the author of pgn-extract and, as has been pointed out, it doesn't hook up directly with a chess engine. However, if you would like to try out something I recently wrote that does interface with an engine then there is a description of a UCI-based analyser that can output annotated PGN via its --annotatePGN option. It is still a little experimental and you will need to compile from source but it might provide something close to what you are looking for.
> 2 votes

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Tags: engines, database, programming
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