title: 1. e4 with backup plan

text:
# Question
Title: 1. e4 with backup plan
I recently started playing 1. e4. Since black has a big choice of replies, I would like to learn one opening at a time. If black plays something I haven't learned yet, I would like to resort to a King's Indian setup (pawns on d3, e4, g3, bishop on g2 and knight on f3) which I am familiar with and enjoy playing.

Obviously this backup plan does not work with all of black's replies (e.g. not with the Scandinavian 1. e4 d5). With most others it should be ok-ish, but perhaps there are also slight differences.

My question is: Against which openings is the KIA setup not all that great? Or alternatively, which openings should I learn first so that I don't have to resort to the KIA backup plan?

# Answer
> 5 votes
When you play 1.e4, you should have a plan against:

1. d5 - Scandanavian
2. Nf6 - Alekhine's
3. d6 - Pirc
4. c6 - Caro-Kann
5. g6 - Modern
6. c5 - Sicilian
7. e5 - King's Pawn
8. e6 - French
9. Nc6 and other garbage.

I would say you can go for a King's Indian Attack setup against all of them except the Scandanavian and the King's Pawn openings. You just need to know where to place your pieces based on your opponents opening choices and what pawn structures you want to achieve against them.

So, Scandanavian and 1...e5 it is not so great against. Everything else you can make do with minor tweaks. I like 1.e4 d5 2.exd5 and if 2...Nf6 3.Bb5+ lines in the Scandanavian. White gets easy development and Black's pices sort of get in each others way a bit.

# Answer
> 3 votes
Depends on your style somewhat. I'm not sure I would like using KID setup against black playing e7-e5 at some point. I think the best openings for this backup plan are Sicilian and French, where e7-e5 is ranging from dubious to impossible. And for sure these two are theoretically the most heavy. In systems like Caro, Pirc, Alekhine I would prefer better backup plan. In e4e5 I would go for d3 Italian instead. But I can imagine some players like bishop on g2 even in e4e5 structure and then there is only Skandinavian left. Even against that I once employed 2.d3 but it is not very good.

# Answer
> 2 votes
As long as you dont expect an opening edge you can play KIA against sicilian, french and caro-kann. The KIA is most often played against the french and e6 sicilian, but it can also be used with somewhat less sting against the caro and other sicilians. This is pretty good as it covers 3 out of the 4 main replies. So you should start by learning 1.e4 e5 and then go covering the rest latter. Against stuff that isnt the 4 main replies you can get away with simple development untill you have the main lines covered.

---
Tags: opening, 1.e4, kings-indian
---


# Question
Title: Pros and Cons for black in Queen's Gambit Accepted
I'm a beginning chess player and still learning the opening. If white's first move is 1.d4 and black counters with d5 (closed or semi-closed games), and white's second move is c4 bringing the Queen's Gambit, black counters with dxc4. What are the pros and cons for black? Thank you for your answer.

# Answer
> 4 votes
A super-abridged guide to the QGA (Queen's Gambit Accepted) is that Black temporarily cedes the center with dxc4, and hopes to develop rapidly while White recovers the pawn (you'll want to look up some key lines where Black suffers because he is greedy and tries to hold on to the pawn; personally, I found it instructive to look at the main line of an entirely different opening called the Noteboom Variation, where Black has better chances to hang on to the pawn, but White's tricks *still* recover it), and then—just before White can start to cash in on his central advantage—play c5 in an attempt to nullify the center.

For example, a sample line (not necessarily main line; it lacks some "professional subtleties" that, as others said, you really don't need to memorize as a beginner):

```
[FEN "rnbqkb1r/pp3ppp/4pn2/8/2Bp4/4PN2/PP3PPP/RNBQ1RK1 w kq - 0 7"]
1. d4 d5 2. c4 dxc4 3. e3 Nf6 (3... b5? 4. a4 c6 5. axb5 cxb5 6. Qf3 {Winning White material}) 4. Bxc4 e6 5. Nf3 c5 6. O-O cxd4

```

In the above ending position, White has the option to either cede the center himself with Nxd4, or give himself an IQP (isolated queen's pawn) where he accepts what could turn out to be an endgame weakness (an isolated pawn) in exchange for a middle game catalyst (the White pawn will serve as a powerful battering ram and outpost provider that Black must stop at all costs).

However, Black will have his work cut out for him trying to actually gain the upper-hand over White, whose spatial advantage allows him to develop relatively more comfortable than Black. If you want something that's a bit less of an "exposed" opening for Black, I might recommend the French or the Caro-Kann which has the same idea of ceding the center only to counterattack with c5 (unfortunately, of course, neither of these are likely with 1. d4).

# Answer
> 2 votes
If you are a beginner, studying tactics, general opening principles and some strategy first will be more useful than learning any opening.

Basically the idea of the queen's gambit for white is to remove a central pawn (the one on d5) and then to occupy the center (general opening principle).

As with any opening theory it does not stop at the second move, dxc4, so it is difficult to make a general statement.

Black has won a pawn, but it is not easy to keep it without concessions, specifically if you want to protect it you will have to put the queenside pawns all (or most) on light squares (a6, c6, b5, c4) which in turn weakens the dark squares and in many cases also locks in the light squared bishop on c8. So in many cases black is happy to return the pawn.

# Answer
> 1 votes
As was said already: "If you are a beginner, studying tactics, general opening principles and some strategy first will be more useful than learning any opening."

I would add End Games to that important list, and modify the opening principles to include you being able to play "the first 4-6 moves as black against anything comfortably". This is not learning opening theory - this is your anti-surprise, beginner's opening preparation, and will give you a starting point to figuring out what you like without getting smeared off the board.

For that, check out Chessable

When a beginner complains "I hate playing against the Sicilian" my answer to that is "well, what have you done to prepare against that?", and usually the answer is "I hope they play the Ruy Lopez" or "I play 1.d4", both insufficient.

Seek general opening advice from better players. Maybe invest is a couple beginner books like Winning Chess Openings, which is right in your wheelhouse.

Learn to walk before you run, and play often.

---
Tags: opening, queens-gambit, queens-gambit-accepted, closed-position
---


title: Engine against non-perfect players

text:
# Question
Title: Engine against non-perfect players
Chess engines are built to find the best move with the assumption they are playing against a perfect player. My question is, is there an engine out there or would it be easy to create an engine that focuses more on winning quickly against weak human players.

For instance, maybe this engine notices that in a position, it capture a minor piece, but this would open up a 10 move tactic in which the opponent could win a rook. Perhaps this engine would risk capturing the piece and go for a quicker win under the assumption that the human player would not see the tactic.

# Answer
> 4 votes
**Short answer**: No such thing

**Long answer**: Contempt factor noted by @Tony is close but not exactly what you are looking for. It is a scaling constant for changing the evaluation score. It is a simple technique for avoiding early draws against apparently weaker opponents, or to prefer draws versus stronger opponents otherwise.

Other techniques that can influence the engine:

* Run multi-pv analysis, and choose a move from the principal variations
* Randomly add noise to the search
* Slow down the engine
* Fixed depth or fixed number of nodes
* ......

But they are still not what you are looking for, because chess engine **always** assume a perfect opponent. Why? That's because the alpha-beta framework always prune bad moves. The framework **doesn't allow** for dirty cheap tricks.

Let's think about it. It's actually not trivial to code an engine that makes dirty tricks. How does an engine know the tricky would work for a human player? Maybe it's just a gross blunder?

It's hard to to tell the engine:

* When to swindle vs when to defend
* How a human player would fall into a trap
* Stupid blunder vs great swindle

---
Tags: engines, analysis
---


title: Chess team tournament regulation query

text:
# Question
Title: Chess team tournament regulation query
I have a doubt ... wat if in a 5 member team during tournaments 3 of the team members fail to turn up , can no 4 and 5 promote themselves to board 1 and 2?

# Answer
> 0 votes
## Sportsmanship demands that the strongest players play at the highest boards. Period.

Unfortunately, as simple as this statement it, it is so difficult to enforce that it is often completely omitted from tournament rulebooks. In scholastic chess, most players are unrated and the directors must rely on the honor of the coaches. In my personal experience as a tournament director, the violation of this principle is the "trick" that honest players and coach most despise, and yet hardly a scholastic tournament occurs without at least one team violating it.

## This "shuffling" tactic robs the strong players on both teams the opportunity to play competitive, meaningful games and violates the spirit of the game.

What makes chess such a princely game is that everything is in plain view - there is scant luck and zero subterfuge, only preparation and skill. The board-shuffling strategy works only because the real strength of the players has been hidden from the opponents and the tournament director. There are many other sports and games where such tactics are allowed or even encouraged, but most of us are attracted to chess precisely because the game is almost entirely free of such features. Chess is one of the purest tests of skill and preparation available to mental athletes. When we want a test of deception, we move to the card tables.

## If a team cannot fill every board, it must fill in the highest boards first.

A missing player is obviously the weakest on the team - at least for that round. Every team competition that I have been a part of has enforced this rule.

---
Tags: rules
---


title: Improvement of chess engines over time

text:
# Question
Title: Improvement of chess engines over time
Chess engine strength has increased considerably over time due to increase of computer strength, but also improvement in algorithms/parameters.

Is there any statistics or graph out there which shows this improvement? Perhaps something like computer Elo vs time and compared to computer strength!?

# Answer
There is a post about Stockfish improvement over the years.

http://talkchess.com/forum/viewtopic.php?t=62822
> 2 votes

---
Tags: engines, history, statistics, computer-chess
---


title: Please analyze my game

text:
# Question
Title: Please analyze my game
Here is a recent game I played and I know it is bad, but wanted some input on ways to improve.

```
[FEN ""]
1.e4 e5 2.f4 Nc6 3.Nf3 d6 4.d4 Bg4 5.h3 Bxf3 6.Qxf3 Nf6 7.Bc4 Qd7 8.f5 Nxd4 9.Qd3 b5 10.Bb3 h5 11.c4 Rb8 12.Nc3 b4 13.Nb5 Rb7 14.a4 g6 15.O-O Bh6 16.Qd1 gxf5 17.Rxf5 Nxf5 18.exf5 a6 19.Bxh6 Rxh6 20.Qc1 axb5 21.Qxh6 Qxf5 22.Qh8+ Ke7 23.c5 dxc5

```

I resigned, but I find it difficult to see where the worst moves were.

# Answer
Before I answer I'm sorry if my english is bad. This game opening using King's Gambit declined (C30). I make the assumption that you are aggressive player who like open game than close game based on your opening and moves. In my opinion the several your mistakes and blunders is:

* 5.h3; the best move is 5.d5. Why d5? Because you can push your opponent knight and you winning the center position. If your opponent play 5...Nd4, you can counter with 6. Be3 Nxf3+ 7.gxf3 exf4 8.Bxf4 Bd7 9.Nc3.... You absolutely win the center and have a pole position to develop your pawns and pieces
* 7.Bc4; Black move in 6...Nf6 is mistake, 6...Nd4 is better than 6...Nf6 because he can push your Queen. But you counter with Bc4, the move that you should take is 7.Bb5 because you can freeze your opponent knight. If your opponent moves is 7...exd4, you can counter with 8.0-0 and makes your opponent pawn hanging in the center
* 8.f5, Black move in 7.Qd7 is bad, but your counter move 8.f5 is bad too, you can counter with 8.d5. You will lost your pawn in the center if you take the other move than 8.d5
* 11.c4, In my opinion, black move in 10...h5 is not good. I don't know what his plans but he should take 10...c5 to backup the knight in d4 and can push your Queen and Bishop. Your move should 11.0-0 make your King safer than before. But Black made a mistakw again with 11...Rb8. He should take your pawn in c4 and next move maybe 12.Qxc4 d5 13.exd5. He make your f5 pawn hanging.
* 13.Nb5. It makes your bishop in b3 taken by Black knight
* 14.a4. Maybe it's your biggest mistake in this game. Your opponent 13...Rb7 is bad move. You can obtain his knight in d4 with your knight and next move is 14...exd4 15.Qxd4. You got his pawn in center!!!!
* 15.0-0. Black second biggest mistake is 14...g6??? He can focus in his right side(A-D) and push your pawn. The best Black move is 14...Nxb3. Your counter is very bad. You should still take the 15.Nxd4 move.
* 16.Qd1. And this is your biggest mistake too. You are lead the game if you take 16.Nxd4 move. 3 move and maybe you still don't realize this is your greatest move so far in this game
* 17.Rxf5. Another biggest mistake too. 4 move and still don't realize.
* 20.Qc1. 20.Qf3 is better
* 22.Qh8+. 22.Rf1 is better
* 23.c5. 23.cxb5 is better

This is my analyze. I'm sorry if I made a mistake too in this analyze
> 2 votes

# Answer
These are my first thoughts, without the aid of a computer:

```
[FEN ""]
1.e4 e5 2.f4 Nc6 3.Nf3 d6 4.d4 Bg4 5.h3 {5.h3 is a wasted move. Putting the question to the bishop doesn't make sense, as Black wins a pawn by removing a defender: 5. h3? Bxf3 6.Qxf3 Nxd4} Bxf3 6.Qxf3 Nf6 7.Bc4 Qd7 8.f5 {8.f5 takes the tension off the pawn centre and closes the f-file, which negates the point for White's play in the King's gambit, i.e. to play against the f7-square, for example with a rook on f1.} Nxd4 9.Qd3 b5 10.Bb3 h5 11.c4 Rb8 12.Nc3 b4 13.Nb5 Rb7 14.a4 {Why not retain the 2-bishops and regains a pawn with 14. Nxd4 exd4 15. Qxd4?} g6 15.O-O Bh6 16.Qd1 gxf5 17.Rxf5 {17.Rxf5 simply loses the exchange for no compensation.} Nxf5 18.exf5 a6 19.Bxh6 Rxh6 20.Qc1 axb5 21.Qxh6 Qxf5 22.Qh8+ {This check doesn't lead anywhere a the queen is not supported. I would have played 22. cxb5 followed by Rf1, placing pressure on f7, f6 and f5.} Ke7 23.c5 {I still don't see a reason for not taking the b-pawn or playing Rf1.} dxc5

```
> 1 votes

# Answer
* 5.h3 is just bad and unnecessary at the time. 5.d5 is to the point.
* 6...exd4 or 6... Nxd4 is direct and obvious.
* 7.d5 again
* 7...Nxd4 again
* 8.d5 Nd4 9.Qd3 is asking to be played again. 8.f5 is the wrong pawn push.
* 11. Bg5 or 11.Nc3 are both better and developing moves.
* 13.Ba4 c6 14.Nd5 is a nice tweener.
* 13...Nxb5 14.cxb5 Qxb5 and your compensation is hard to find.
* you should trade on d4: 14. Nxd4 exd4 15.Qxd4 followed by 0-0 and Bf4 is so much better and direct.
* after your move 14.a4, black should trade Nxb3 (a knight not long for this word for White's good bishop) and snap Nxe4. At this point, White is busted.
* again, 15 Nxd4 is screaming at you. You must end this love affair with the Nb5.
* 15...Nxb3 again. Black should have played this move at any point in the next few moves.
* 16.Qd1 is ... weird. You need to justify that move here with your thinking process. I can't find a reason to play that move. It does not cover any square the queen already covers on d3, and in fact, leave the e-pawn unguarded. Why you do not play Nxd4 is ... uncertain. 18...Bxc1 19.Rxc1 a6 wins for black. The care and feeding of your pieces has gone unattended.

So, black opens lines against his king for you and you resign. Clearly after Rd1 white has the edge. 24.Rd1 Ne8 25.Rf1 Qg5 16.Rxf7+ +-.

Lots of tactical oversights that are definitely fixable and should have been seen.

If you are looking for advice it would be stop playing the kings gambit. You are insufficiently skilled in tactics to play such an opening, based on this game. Of course, you can take your lumps and keep playing it. It is just a game.
> 1 votes

---
Tags: learning
---


# Question
Title: What is the idea behind playing 6.a3 in the Sicilian Najdorf?
What is the idea behind playing 6.a3 in the Sicilian Najdorf?

```
[FEN ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. a3

```

This seems to be getting popular at the highest level (e.g. yesterday/today's games at the Tata Steel Masters, Carlsen - Wojtaszek, Karjakin-Giri).

Is it just a waiting move or is there some deep idea behind it? As far as I am aware in most lines black is not aiming to put any piece on b4 (which would be prevented by 6. a3). In the poisoned pawn variation a3 prevents the capture Qxb2, but other than that, I don't see what white wants to achieve with 6. a3. Is he preparing to play b4?

# Answer
The move a3 serves basically two functions:

1. White can develop the bishop to c4, and keep it aimed on d5, even if Black attacks it with b5, or, as Giri did, with Be6. In the lines where Black plays ...e5, the battle for d5 is often very important so it *could* be worth spending a tempo in it.
2. Black often plays b5 to gain some space on the queenside. The move a3 then discourages a further advance of the pawn to b4.

Another reason to choose this line could be that the main line is heavily analyzed, beyond the 20th move, and the White players didn't want to engage in a theoretical battle. This would especially apply to Carlsen who often plays 'sidelines', and this tweet from Karjakin confirms it as well:

> The only reason why I played 6.a3 against @anishgiri is that I forgot adaptor for my laptop and I urgently had to create a new ideas

Thanks @DagOskarMadsen and @DavidRicherby for drawing my attention to this tweet.
> 9 votes

# Answer
Pawn b7 generally wants to threaten knight on c3 at some point so definitely there is one piece that is interested in b4 square. But a3 is not developing move in open position so the deepest idea of this system is probably its surprise value.
> 6 votes

---
Tags: opening, sicilian-defense, najdorf
---


# Question
Title: ECO D35 for Game Analysis,- Queen's Gambit Declined: Queen's Knight Variation, 3...Nf6 game for analysis
Queen's Gambit Declined: Queen's Knight Variation, 3...Nf6 game for analysis.

Here is the PGN

```
[fen ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2017.01.17"]
[White "anandsadasivam"]
[Black "RandyDoce"]
[WhiteElo "684"]
[BlackElo "687"]
[TimeControl "600"]
[ECO "D35"]
[Result "1-0"]
[Termination "anandsadasivam won by checkmate"]
[CurrentPosition "5Q1k/2P3p1/8/4P2p/2rPB3/4PN2/PP1K1b2/R1B4q b - - 2 33"]

1.d4 d5 2.c4 Nf6 3.Nc3 e6 4.c5 a5 5.f4 c6 6.h4 Be7 7.Rh3 Ng4 8.e3 Nf6 9.g4 O-O 10.h5 b5 11.g5 e5 12.gxf6 Bxf6 13.fxe5 Bh4+ 14.Kd2 b4 15.Na4 Na6 16.Nf3 Bxh3 17.Bxh3 Rb8 18.Nb6 b3 19.Qxb3 Bf2 20.Bd7 Qh4 21.Bxc6 Qxh5 22.Bxd5 Qh1 23.Qa4 Rbd8 24.Be4 Nb4 25.Qxa5 Nd5 26.Nxd5 Rc8 27.Ne7+ Kh8 28.Nxc8 Rxc8 29.c6 h5 30.Qd5 Rb8 31.Qxf7 Rb4 32.c7 Rc4 33.Qf8#
1-0

```

Here is the fen,

```
[fen "5Q1k/2P3p1/8/4P2p/2rPB3/4PN2/PP1K1b2/R1B4q b - - 2 33"]

```

# Answer
> 3 votes
My move by move analysis see below. Comments appear below the board as you play through the game. Generally a blunder rich game. White seems to like pushing pawns a bit too much, while black played too passively in the beginning. Black should have attacked the strong white center right from the start with b6. Both players neglected the development of their pieces.

```
[FEN ""]
[White "anandsadasivam (684)"]
[Black "RandyDoce (687)"]
[TimeControl "-"]
[Date "2017.01.16"]
[Result "1-0"]
[Termination "Normal"]
[ECO "D35"]
[Opening "Queen's Gambit Declined: Normal Defense"]

1. d4 d5 2. c4 Nf6 3. Nc3 e6 4. c5?! { Gives up the pressure on the d5 pawn. Temporarily gains some space but with correct play by black white will not keep this c5 outpost for long. } 4... a5?! { In structures like this you should attack the pawn on c5 by playing 4...b6 and if white defends it with 5. b4, you play 5. ... a5. In the end black ends up with a slight advantage on the queenside. } 5. f4?! { Weakens the light squares and locks in the bishop on c1. If you want to play f4, it would make sense to first move that bishop out to g5 where it can be exchanged if necessary and only then play f4. This way you avoid having a bad dark squared bishop behind your pawn chain. } 5... c6 { Better would be 5...b6 to undermine the white pawn on c5 and if white plays cxb6 (which is the best move) you can recapture with the pawn on c7. You gain space for developing your pieces, most importantly for the c8 bishop which can go to a6 for instance. After 5... c6 you don't have this option of recapturing with the pawn from c7 anymore and if black played b6 later he'd end up with a weak pawn on c6. Also 5...c6 locks in the bishop on c8. } 6. h4!? { Weakening the light squares even more. It is unclear what the purpose of this move is. } 6... Be7 7. Rh3 Ng4?! { This knight had a very decent position on f6. You should think of how to improve your undeveloped pieces on the queenside instead of moving this knight again. } 8. e3 Nf6 9. g4 O-O { Brave. Castling right into the white attack. } 10. h5 b5?! { Typically when being attacked by a pawn storm on one side, the best reaction is to either open the center or to play on the opposite side (here on the queenside). After b5 white can keep the queenside closed and also in the center there is no counterplay in sight for black. } 11. g5 e5? { This just loses a piece for nothing. } 12. gxf6 Bxf6 13. fxe5 Bh4+ 14. Kd2 b4 { Why not capture the rook with Bxh3? } 15. Na4 Na6 16. Nf3 Bxh3 17. Bxh3 Rb8?! { Nothing to do for the rook here since there are no open files here and black cannot force opening of files either (e.g. ... b3 would be answered with a3 closing the position on the queenside. } 18. Nb6 b3?! { Makes room for the knight to jump to b4, but a better chance could have been an exchange sacrifice with Rxb6. cxb6 and trying to open some lines in the center against the uncastled white king. } 19. Qxb3 Bf2 20. Bd7 Qh4?? { Blunders the queen } 21. Bxc6?? { White should take the queen with Nxh4. } 21... Qxh5 22. Bxd5 Qh1 { Too many queen moves. Improve the pieces that don't do much yet, e.g. 22... Nb4 could be an idea as could bringing one of the rooks to attack the white king. } 23. Qa4 Rbd8 24. Be4?? { Spoils a winning position. } 24... Nb4?? { Nxc5 should be played which wins a pawn, improves the position of the knight and opens the c-line against the white king. } 25. Qxa5 Nd5?? { Blunders a piece as d5 is attacked by two white pieces and only defended by one black piece. } 26. Nxd5 Rc8 27. Ne7+ Kh8 28. Nxc8 Rxc8 29. c6 h5 30. Qd5 Rb8 31. Qxf7 Rb4 32. c7? { Qf8++ or Qe8++ would already be mate. } 32... Rc4 33. Qf8# { 1-0 White wins by checkmate. } 1-0

```

---
Tags: analysis, pawns, game-complexity, eco
---


title: engines keep playing same game

text:
# Question
Title: engines keep playing same game
Just finished writing customizing a chess engine by basically adding a bitboard to the freely availably tscp engine. Now I'm testing it out in winboard and notice that often the two machines will play the same game multiple times in a match. I'd like to add some variety to the games by at least having it pick equal moves at random. I'm just using alpha-beta search with simple move ordering. I'm thinking about just adding a small random number to the leaf nodes to break ties but I don't really like this solution because some of the smaller bonuses that the evaluation function uses are 3-5 centipawns. So I don't have enough "room" for random number to break the ties.

my other thought was to have the engine pick randomly which move to keep when it found an evaluation == alpha. I don't really like this because I suspect it favors moves ordered last in the search.

Question is how can I pick from the equal scoring leaf nodes randomly? and also evenly?

# Answer
> 7 votes
**Note:**

It's a **good** idea for your engine be deterministic. There is no reason to select a move randomly. You would only do it to lower your engine strength. If you make your engine non-deterministic, you will find it very hard to debug and reproduce a bug. My recommendation is **not** to do it.

You shouldn't modify your engine. You may want to use an opening book, and pick a line randomly. Many chess GUI can do that, for example, the CuteChess software. Arena GUI can do also that.

**But if you insist:**

Let's take a look at the Stockfish source code.

```
 Move Skill::pick_best(size_t multiPV) {

    const RootMoves& rootMoves = Threads.main()->rootMoves;
    static PRNG rng(now()); // PRNG sequence should be non-deterministic

    // RootMoves are already sorted by score in descending order
    Value topScore = rootMoves[0].score;
    int delta = std::min(topScore - rootMoves[multiPV - 1].score, PawnValueMg);
    int weakness = 120 - 2 * level;
    int maxScore = -VALUE_INFINITE;

    // Choose best move. For each move score we add two terms, both dependent on
    // weakness. One is deterministic and bigger for weaker levels, and one is
    // random. Then we choose the move with the resulting highest score.
    for (size_t i = 0; i < multiPV; ++i)
    {
        // This is our magic formula
        int push = (  weakness * int(topScore - rootMoves[i].score)
                    + delta * (rng.rand<unsigned>() % weakness)) / 128;

        if (rootMoves[i].score + push > maxScore)
        {
            maxScore = rootMoves[i].score + push;
            best = rootMoves[i].pv[0];
        }
    }

    return best;   }

```
* Stockfish starts multi-PV (not supported in TSCP, so you'll need to code it yourself!)
* Compute a random number and add it to the score for each PV
* Compare each weighted PV, and pick the best one

You may find the following links useful:

**Recommendation:** Don't do it unless you want to weaken your engine.

---
Tags: engines
---


# Question
Title: Associating myself with my FIDE chess profile
I have a USCF rating, but never had a FIDE rating. Two of the recent tournaments I played in were USCF/FIDE events. As a result, I now have a FIDE ID, and a "FIDE Chess Profile" page on the FIDE site. (This happened without my knowledge, but I wanted to "eventually" get a FIDE rating anyway, so I'm very pleased.)

How do I create a login/password **and associate** myself (real life) with that chess profile? (The bold part is the important part.) Specifically, on the FIDE Chess Profile page in question, there are login/password fields on the right side - but since I never initiated getting the ID in the first place, I'm not sure how to let FIDE know that I'm me. I would think this information/process would be easy to find, but I'm having trouble locating it...

This is sort of similar to this question about obtaining a FIDE ID without having played a FIDE event - but I apparently already have the ID.

(For the record, the name/birthday/etc. are all correct, as are the specific tournaments and opponents I played in. I am 100% certain that this really is me.)

# Answer
> 2 votes
Getting a login is easy, free and worthwhile if you want to see your or other players' histories (ratings, titles, performance, etc.) If you click on the link on your FIDE ratings page where it says "Get rating" next to "Online rating not rated" it will take you to the FIDE Online Arena page. Underneath the banner on that page is a menu item "Registration and fees" and in the drop down list when you hover over it is the item "Memberships"

That memberships page describes the different levels of membership available - "Guest Member", "FIDE Member", "Platinum Service". Guest membership is free and is what I have but it does not associate me with my FIDE profile. To do that I would have to join as a FIDE member and pay them 25 euros. On the form that comes up when I want to join as a FIDE member are entries for my name, date of birth, gender email address, FIDE number and the username and password I want to use. For the association to work the details I give would have to match those that FIDE have for me in their database.

---
Tags: fide, websites
---


# Question
Title: How can we convert PGN format to Resource Description Framework (RDF)?
Is there any parser available in which we take PGN data as input and then convert it to RDF format? Has someone worked on this thing?

# Answer
> 4 votes
I do maintain that converter at UPM. You may also want to read the (highly technical) related papers:

# Answer
> 1 votes
I found this website that seems to do exactly what you are asking, as far as I can tell, it is the only resource available for PGN-\>RDF conversion.

The website is http://salonica.dia.fi.upm.es:8080/rdfchess/pgn2rdf.html

Sorry for the link-only answer, but it seems to answer the question.

~CSS

---
Tags: software, pgn
---


title: How to find chess students?

text:
# Question
Title: How to find chess students?
I was wondering how to find chess students or better said how and where one can advertise himself? I am sure that many chess players are searching for a coach, but they don't know where to find him. Here is my page for example, https://bs.lichess.org/coach/PetarBosnjak, have I mentioned all the needed informations, should I omit something?

# Answer
> 1 votes
In the UK the busiest chess forum is the English Chess Forum. They have an Adverts topic which would be suitable for you to use.

I should stress that despite the presence of the letters "ecf" in the url it is independent of the English Chess Federation which has its own web site, although senior members of the board do from time to time make announcements and answer questions on the English Chess Forum. This independence allows a much broader range of opinions to be expressed.

---
Tags: coach
---


# Question
Title: Can you capture a pawn en passant with a king?
Friend right now is trying to en passant me with a king. I'm saying that its not legal.

He won't believe me.

He is saying that any opposing piece can capture the en passant pawn.

# Answer
> 15 votes
An en passant capture is a move that involves pawns, exclusively. In particular, the king is not allowed to capture en passant.

From Wikipedia (link):

> It is a special pawn capture, that can only occur immediately after a pawn moves two ranks forward from its starting position, and an enemy **pawn** could have captured it had the pawn moved only one square forward. The opponent captures the just-moved pawn "as it passes" through the first square. The resulting position is the same as if the pawn had moved only one square forward and the enemy pawn had captured it normally.

# Answer
> 3 votes
First of all, neither a rook nor a knight can make the single diagonal "en passant" move. Of course, kings, queens, and bishops can, so the question is why they do not.

A pawn moving two squares represents a group of lightly armored foot soldiers moving at "double time" (speed, actually). In an en passant move, they are "ambushed" by similar light infantry able to give chase at similar speeds. "Kings" and "queens" represent heavily armored "guards" troops (think bodyguards), commanded by the king and queen respectively. These are heavily armed (and armored) "formation" troops that are not good at hot pursuit. Bishops have been likened to artillery or archery, neither of which are good at chasing lightly armed peasants over broken ground. That's why only fellow pawns can use the *en passant* move.

# Answer
> -1 votes
> any piece that guards that square could in principle capture the pawn on that square.

You're incorrect. I've found numerous references that says that you can't capture en passant with *nothing* but pawns.

http://www.chessvariants.com/d.chess/enpassant.html

---
Tags: rules, en-passant
---


title: Scotch opening 5.Nf3

text:
# Question
Title: Scotch opening 5.Nf3
Yesterday Anish Giri played the scotch opening at the Tata Steel Tournament with the strange looking move(to me) 5.Nf3.

```
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Nxd4 Qf6 5.Nf3

```

What is the idea/plan behind this move after retreating the knight immediately. From my point of view i would assume the knight is better placed on d4 than on f3.

Can white even hope to have an opening advantage after this move?

# Answer
After 4....Qf6, both 5.Be3 and 5.Nxc6 are likely to transpose to 4....Bc5: 5.Be3 Bc5 and 5.Nxc6 Bc5. Instead, 5.Nf3 seems to be an interesting alternative, with chances to obtain an advantage. It worked quite well for Giri, as he was pressing the entire game.

After 5.Nf3, black should probably be able to equalize. Andreikin played the precise 5....Bb4+ and the game continued 6.c3 Bc5 7.Be2 d6 8.0-0. Black followed up with the logical 8....Nge7, but ended up in a worse position after 9.b4 Bb6 10.Bg5. Note that 9....Nxb4 or 9....Bxb4 doesn't work because of 10.Bg5. Instead, 8....a6 and 8....Qe7 (to play Nf6) are probably better alternatives, after which black should be able to keep the balance.

Actually, one can also wonder why black would give white the opportunity of 5.Nf3 by playing 4....Qf6 instead of 4....Bc5. Two possible reasons are:

* After 4....Qf6 5.Nxc6, black wants to play 5....dxc6, instead of 5....Bc5. This way, he can still chose between Bb4, Bc5 or Bd6.
* Black doesn't like the position after 4....Bc5 5.Nb3 Bb6 6.Nc3 Nf6

```

      [StartPly "7"]

      [FEN ""]
      1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Nxd4 Qf6 (4...Bc5 5.Nb3 (5.Be3 Qf6)(5.Nxc6 Qf6) Bb6 6.Nc3 Nf6) 5.Nf3 (5.Be3 Bc5)(5.Nxc6 dxc6 (5...Bc5)) Bb4+ 6.c3 Bc5 7.Be2 d6 8.O-O Nge7 (8...a6)(8...Qe7) 9.b4 Bb6 (9...Nxb4 10.Bg5)(9...Bxb4 10.Bg5) 10.Bg5

```
> 4 votes

# Answer
They're playing on the extremely high level and opening preparation is amongst the things they invest the most of their time so they're always searching for the new ways to spice the game up and thus increase their chances for the victory.I don't think there's a deep idea behind Nf3.
> 1 votes

# Answer
Well, the knight on d4 is attacked, so you have to do something about it. So:

* Exchange on c6: certainly possible, if black recaptures with a pawn he gets a double pawn, but on the other hand gains a tempo for developing the light square bishop.
* Defending via Be3: also possible, but you might develop that bishop later on to a better place like g5 without losing a tempo.
* Defending via c3: possible, but that's blocking the natural place for the Nb1
* Nb3: Naa, don't like it. It looks a little too passive to me, although it's probably perfectly playable.
* Nf3: Why not? The knight is out of trouble, after Nc3 you can bring your bishop to g5 kicking the queen with tempo, also defending the king after castling king side and it's placed absolutely harmoniously on f3.
> 0 votes

---
Tags: opening, 1.e4, scotch-game
---


# Question
Title: What can be the variation name of this complete game which falls on ECO C02
When I had looked at

> http://www.chessgames.com/perl/chessopening?eco=C02

there are 4,893 variations found for ECO C02.

Is this variation can have some name from among 4893 variation, sorry for asking from the count I just asked as its in ECO. However I want some better analysis for this game.

Except one pawn move which I had planned to do before on its turn.- `10 .. g5`, I tried my ability well, rather maybe not atlast.

```
[fen ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2017.01.11"]
[White "Meketrex"]
[Black "anandsadasivam"]
[Result "1-0"]
[ECO "C02"]
[WhiteElo "713"]
[BlackElo "668"]
[TimeControl "600"]
[Termination "Meketrex won by checkmate"]
[CurrentPosition "4Q3/bb3Q2/p1k1p3/Pp1pP2p/1Pp2P1P/2P3P1/R3q3/KN6 b - - 3 37"]

1.e4 {[%clk 0:09:59]} e6 {[%clk 0:09:54]} 2.d4 {[%clk 0:09:54]} d5 {[%clk 0:09:47]} 3.e5 {[%clk 0:09:46]} Nc6 {[%clk 0:09:25]} 4.g3 {[%clk 0:09:42]} Bb4+ {[%clk 0:09:08]} 5.c3 {[%clk 0:09:36]} Ba5 {[%clk 0:09:03]} 6.b4 {[%clk 0:09:28]} Bb6 {[%clk 0:08:58]} 7.a4 {[%clk 0:08:55]} a6 {[%clk 0:08:49]} 8.a5 {[%clk 0:08:47]} Ba7 {[%clk 0:08:47]} 9.Bg2 {[%clk 0:08:37]} b5 {[%clk 0:08:39]} 10.Qg4 {[%clk 0:07:56]} g5 {[%clk 0:08:34]} 11.Bxg5 {[%clk 0:07:53]} Qd7 {[%clk 0:08:14]} 12.Nf3 {[%clk 0:07:09]} h6 {[%clk 0:08:10]} 13.Bf6 {[%clk 0:07:00]} Nxf6 {[%clk 0:08:00]} 14.exf6 {[%clk 0:06:58]} h5 {[%clk 0:07:54]} 15.Qg7 {[%clk 0:06:55]} Rf8 {[%clk 0:07:31]} 16.Ng5 {[%clk 0:06:53]} Bb7 {[%clk 0:07:21]} 17.Nh7 {[%clk 0:06:50]} O-O-O {[%clk 0:07:16]} 18.Nxf8 {[%clk 0:06:48]} Rxf8 {[%clk 0:07:12]} 19.Qxf8+ {[%clk 0:06:46]} Nd8 {[%clk 0:07:10]} 20.Qh6 {[%clk 0:06:22]} e5 {[%clk 0:06:58]} 21.dxe5 {[%clk 0:06:08]} Qf5 {[%clk 0:06:55]} 22.f4 {[%clk 0:05:57]} Ne6 {[%clk 0:06:43]} 23.Qh8+ {[%clk 0:05:16]} Kd7 {[%clk 0:06:36]} 24.h4 {[%clk 0:03:59]} c5 {[%clk 0:06:32]} 25.Bh3 {[%clk 0:03:54]} Qe4+ {[%clk 0:06:27]} 26.Kd2 {[%clk 0:03:33]} Qxh1 {[%clk 0:06:13]} 27.Bxe6+ {[%clk 0:03:14]} fxe6 {[%clk 0:06:05]} 28.f7 {[%clk 0:02:50]} Qg2+ {[%clk 0:06:02]} 29.Kc1 {[%clk 0:02:42]} Qg1+ {[%clk 0:05:55]} 30.Kb2 {[%clk 0:02:40]} Qf2+ {[%clk 0:05:49]} 31.Ka3 {[%clk 0:02:38]} Qc2 {[%clk 0:05:14]} 32.Ra2 {[%clk 0:02:27]} Qa4+ {[%clk 0:05:04]} 33.Kb2 {[%clk 0:02:22]} Qd1 {[%clk 0:04:41]} 34.f8=Q {[%clk 0:02:17]} Qe2+ {[%clk 0:04:38]} 35.Ka1 {[%clk 0:02:12]} c4 {[%clk 0:04:17]} 36.Qf7+ {[%clk 0:02:09]} Kc6 {[%clk 0:04:12]} 37.Qhe8# {[%clk 0:01:40]}
1-0

```

Here is the fen

```
[fen "4Q3/bb3Q2/p1k1p3/Pp1pP2p/1Pp2P1P/2P3P1/R3q3/KN6 b - - 3 37"]

```

# Answer
> 3 votes
C02 is the French advance variation. *If handled properly* it is characterized by white gaining space in the center with white pawns typically on b2, c3, d4, e5, f4. The center is closed and black is challenging the white pawn chain from the side playing c5 and often f6. Only after c5, the black knight will go to c6 in order to increase the pressure on the white d4 pawn.

Now in your game black does none of this and allows white to expand even more creating no counterplay. Since 3. ... Nc6 is already a bad move (c5 is best and by far the most popular) this whole line does not have a name. Note that attacking the center with pieces only (e.g. with Nc6) does not pose any problems for white as after c3, black will not be able to take on d4 with knight or bishop without losing material.

---
Tags: analysis, french-defense
---


# Question
Title: Funny games for 1 player with chess theme
I'm looking for some ideas on good games for one player (to create) that would be enjoyable, fun and with at least a little chess logic.

I already created one that I very like. Searching for pairs of white and black piece of same value in symetric material positions **from real games** (P:P, B:B, N:N, R:R, Q:Q, K:K). Looks like the picture. One must be very careful to reveal all pairs without single error, pawns help a lot but by far not easy. Understanding pawn structures, typical openings very helps here so this is the chess part for this game.

Similarly I made also one where you are looking for pawns knowing count of pawns and knowing where pieces stand. Clicking empty square is error obviously in this game. Not bad but the first is better :)

Any ideas for not very hard games that would be funny on touch screen devices are welcome. Preferably games that will be funny to play repeatedly. It is no problem to search for whatever type of positions necessary in game database, but I don't like creating random positions that aren't real as the chess value of such games would probably be very low...

Edit: Does not neceassarily have to be logical but can be memory game or ever some quiz or game for fast decison making.

# Answer
> 3 votes
1. find the most/least attacked square (or some other special square) on the board quickly
2. arranging pieces on the board with a certain condition (this can be the classic 8 queens problem, but also other pieces with other condition); perhaps not realistic enough for you, though IMO this can teach you a lot about how the pieces move
3. guess the opening based on some position
4. guess the move in a famous game; perhaps too close to chess for your purpose
5. some retrograde problems

# Answer
> 0 votes
Ubisoft's *Chessmaster* program had a few fun games:

* **Fork my fruit**:

> move pieces to a square so that they can fork whatever fruit is in their line of movement.

Quote source: ign

* **Minesweeper**:

A game where you diffuse hidden mines by not running over them and diffusing them, similar to capturing.

* **Snake**:

> where the player chooses a long-range chess piece, then trying to make a long tail using captured pieces, and avoiding the enemy pieces to capture the main piece or tail parts.

Quote source: wikipedia

---
Tags: chess-variants
---


# Question
Title: Stockfish crashing on checkmate positions, and erroneous evaluation
I asked the same question on Stockfish's forum.

Black to move in the classic scholar's mate position. mate in 1. Engine produce erroneous results?

```
position fen rnbqkbnr/pppp1ppp/8/4p3/6P1/5P2/PPPPP2P/RNBQKBNR b KQkq -

eval

Total Evaluation: -0.85 (white side)

```

Same position, except black checkmated white. White to move:

```
position fen rnb1kbnr/pppp1ppp/8/4p3/6Pq/5P2/PPPPP2P/RNBQKBNR w KQkq -

eval

Debug error! abort() has been called

```

Here is another position that crashes:

```
1b1B1k2/8/2B1p1p1/3n1p2/4KP2/6P1/8/8 w
eval

```

`Go` seems to work properly, showing that its mate in 1, and checkmate. However `eval` is not showing the correct numbers.

Or am I misunderstanding something here?

# Answer
Everything works perfectly.

* You should add 50 move counter to your FEN, but this is not the biggest issue.
* The `eval` command returns a **static** evaluation of your position. It **doesn't** start the search, that's why Stockfish gave you back the results immediately.

Try this:

```
ucinewgame
position fen rnbqkbnr/pppp1ppp/8/4p3/6P1/5P2/PPPPP2P/RNBQKBNR b KQkq - 0 1
go movetime 1000

```

The engine gives you back mate in one:

```
info depth 126 seldepth 2 multipv 1 score mate 1 nodes 3781 nps 945250 tbhits 0 time 4 pv d8h4

```
> 0 votes

---
Tags: engines, stockfish
---


title: French defence vs Sicilian defence

text:
# Question
Title: French defence vs Sicilian defence
I'm beginner chess player who like aggressive play. I often counter e4 with e6(french defence) or c5 (sicilian defence). But I still don't know what's detail pros and cons with these openings. Can anyone explain me? Thank you very much for your answer. I appreciate that

# Answer
The French and the Sicilian are almost as different openings as you could get as a response to 1. e4. The French (especially the Advance Variation, which is the most common among amateur play) tends to lead to closed positions, that is, positions clogged up with stable pawn chains where long-term maneuvering and strategy prevail. The Sicilian (as much as there is a "single" Sicilian, seeing as the multitudinous Sicilian systems can range from quiet and defensive \[cf. the Sheveningen\] to dangerous and aggressive \[cf. the Dragon Variation, or the Sveshnikov\]) tends to lead to open or semi-open positions, and the tide of play may shift within just a couple of moves owing to tactics.

There's really not much to be said in terms of meaningful, general, and objective "pros" and "cons" of the two opening systems. I would just study very briefly the theory behind the first few moves of each, play several games with them, and decide for yourself which you like to play. They're both super-solid in principle and played all the way up to the GM level.

(If you say you like aggressive play, I tend to think you'd like the Sicilian as such. The French is still among my favorites, however, because as Black you're constantly making White react to your threats of winning small but significant positional or material gains whilst in the opening. As a beginner I found games almost played themselves and if White wasn't keen on defense I would obtain the upper hand.)
> 3 votes

# Answer
Each opening is good for trying to introduce potential imbalances. The Sicilian is very popular, and you may have to learn a few opening lines, but don't memorize too much. You'll recognize move-groups or ideas or piece formations that work. Playing ...d5 is generally the goal.

The only drawback is that White can often have a general plan against any sicilian e.g. f4 O-O with a kingside attack, or a quick g4-h4-(g5/h5) with O-O-O. You need a certain degree of confidence against both.

The French Defense often leaves you with a space disadvantage and a bad queen's bishop, since White often plays e5. Black's moves also feel relatively logical if you look at a few GM games. And "just developing" often gets White's position in hot water if he doesn't understand his weaknesses.

I learned a lot about pawn chains and such from playing the French Advance: e4 e6 d4 d5 e5 c5 and Black can do a lot on the Queenside. It's also relatively harder for White to sacrifice soundly against the French. The Milner-Barry is about all there is, though the Alekhine-Chatard can be a pain if you play e4 e6 d4 d5 Nc3 Nf6 Bg5 Be7 e5 Nfd7... h4!? burned me.

But the big drawback of the French is e4 e6 d4 d5 exd5 exd5, the exchange, which is potentially boring, and lower rated players may use it to try to draw against you and frustrate you.

I played the French when I was younger. Sometimes I wondered if I should've gone with the Sicilian. There's no wrong answer.
> 1 votes

---
Tags: opening, sicilian-defense, french-defense, aggressive-play
---


# Question
Title: Chess games ownership, databases to use in app to sell
There is plenty of sites offering database searches and I wonder how to make it without breaking any laws. I'm looking for games source (pgn ideal) that I can download, process and use in my application. Looking for both human and correspondence sources. No big problem if the work is heavy or difficult. Interested just in new games so if some sources started just a few years ago, no big deal. How complete various sources are? Can I just pack the database to my own format and offer it as a free download?

# Answer
> 5 votes
Nobody has copyright to raw PGN games, so you are free to distribute it. You may pack it to your own format, you may offer it as a free download, or you may sell it.

However, you can't sell annotation. You may use Chessbase's `2017 Mega Database`, get the games, remove annotation (if any) and use the games for your app.

---
Tags: database
---


# Question
Title: The best way to continue King's Gambit Accepted as White after 3 ... Be7
I have some concern when playing King's Gambit as white but it's interesting. After:

```
[FEN ""]
1.e4 e5
2.f4 exf4
3.Nf3 Be7

```

What is the best move for white?

# Answer
The black threat of Bh4+ is not really ones, white should play Bc4 in this position. Releasing the f1 square for the king after the check on h4. After the check white cannot castle anymore but the bishop on h4 is not very happy, black can't play the g8 Knight and need to spend one more tempo on retreating the bishop.

If black don't give the check, white could just occupy the center with the d4 pawn, castle and capture back the f4 pawn with a nice game.
> 10 votes

# Answer
In this position, 4. Bc4 is played the most. It continues White's development, and 4. Bc4 makes room for the king on f1 (which isn't a bad square, at least not any more than h4 is a bad square for the black bishop). E.g. after 4. Nc3, Black can play the nasty 4... Bh4+, forcing the king to move to e2. The calm 4. Be2 works as well, but I feel it is less in the spirit of the King's Gambit, which is an aggressive opening.
> 7 votes

# Answer
4.Bc4 is a good move here. The line usually worried about, the bishop check 4...Bh4+, often leads to a line with strong, aggressive chances for White. Sacrificing pawns and using black's pawn for protection, 4...Bh4+ 5. g3 fxg3 6. 0-0 gxh2 7. Kh1 gives's White's king surprisingly strong safety as well as piece development and attacking chances.
> 5 votes

# Answer
As a regular 3, ... Be7 player, I can say that Be7 is not played to give an immediate check on h4. As others pointed out the best move is 4, Bc4 but white must be aware of the several tactics that could arise in this position. For example after the natural 4. Bc4 attacking the f7 pawn,

```
[FEN ""]
1. e4 e5
2. f4 exf4
3. Nf3 Be7
4. Bc4

```

Black would simply develop his knight to f6.

```
[FEN ""]
1. e4 e5
2. f4 exf4
3. Nf3 Be7
4. Bc4 Nf6

```

The idea is to attack the central e4 pawn and plan a trick if white tries to protect the pawn by 5, Nc3 then comes

```
[FEN ""]
1. e4 e5
2. f4 exf4
3. Nf3 Be7
4. Bc4 Nf6
5. Nc3 Nxe4

```

if 6, Nxe4 then 6, ... d5 wins the piece back with a fine position.

```
[FEN ""]
1. e4 e5
2. f4 exf4
3. Nf3 Be7
4. Bc4 Nf6
5. Nc3 Nxe4
6. Nxe4 d5

```

I have seen most players would give back the piece immediately after 5 ... Nxe4 by 6, Bxf7+ Kxf7 and then 7, Nxe4

```
[FEN ""]
1. e4 e5
2. f4 exf4
3. Nf3 Be7
4. Bc4 Nf6
5. Nc3 Nxe4
6. Bxf7+ Kxf7
7. Nxe4 d5

```

This is a perfectly playable position for black. The king could seek shelter in g8 after developing the rook to f8 or e8. The bishop at e7 guards the possible knight maneuvers and there is no real threat of decisive attack in this position.

There are many more interesting variations after 4, Bc4 but I am stopping here as the OP would likely be able to discover them without much effort.
> 4 votes

---
Tags: opening, kings-gambit
---


title: How did castling originate?

text:
# Question
Title: How did castling originate?
Castling to me has always seemed like such a huge leap in terms of game play that I've always wondered how it came to be.

**Does anyone know the history behind how and why castling came to be?**

# Answer
Per Wikipedia:

*Castling was added to European chess in the 14th or 15th century and did not develop into its present form until the 17th century. The Asian versions of chess do not have such a move.*

The King seems to have always moved the same as at the present, except that the game used to be played until he was actually captured. Because of the King's vulnerability due to the Queen's enormous scope and power, several methods of "castling" were tried before the 16th century.

One method was to allow the King to move two or three squares on its initial move. Another method was to allow the King to move directly to g2. The present method of castling was documented as early as Ruy López's 1561 work *Libro de la invención liberal y arte del juego del Axedrez*.
> 13 votes

# Answer
There seems to have been a rule in medieval chess, that does explain the invention of castling at least partly:

"The King's leap: for his first move, the King could jump at the 2nd square vertically, horizontally, diagonally or like a Knight. From e1 he could jump on c1, c2, c3, d3, e3, f3, g3, g2 ou g1. He could jump over an occupied square but not over a square under threat by an opposing piece. He could not capture with this leap nor jump to escape a check. However, he could still leap if he had been put in check on the previous moves."

http://history.chess.free.fr/mediaeval-chess.htm

Shatranj (and this variation of it) was a slow game and the king much less vulnerable then in today's chess (basically like a complicated endgame). So to speed it up, you could centralise your king in one move. When the queen and bishop suddenly got powerful, the king's leap was better used to hide your king away. Turning the rook move and the inevitably following king's leap into one move is very similar to turning the first two moves of a pawn into one double move.

So the introduction of castling was more evolution than revolution … ;-)
> 12 votes

# Answer
Lasker in his Manual of chess refers to the King's leap when he writes about the fianchetto. He says that the fianchetto originated to provide a safe square for a king with the king's leap
> 2 votes

---
Tags: rules, castling, history
---


title: Why does black not move Queen here?

text:
# Question
Title: Why does black not move Queen here?
in this board, after Nf5 as indicated, why does stockfish suggest the best move is king-knight e7? Surely it would be better to save the Q to h7 towards the check-mate on h2 (white knight blocks the white bishop, so Q safe here). Any ideas? Am I missing something obvious? Thanks.

# Answer
Nf5 ...Qh7, Nd6+ (discovered attack) wins the queen. Note that any other attempts to save the queen fails:

* Nb4 or Nce7 or Nge7 or Nf6 with the idea to attack the white queen fail because Nxg7+ is check
* Qg6 has the same problem as Qh7, i.e. loses the queen after Nd6+
* Qxe5 Rae1 (or Rfe1) pins the queen. Unpinning the queen with Nge7 (or Nce7) and an attack on the white queen does not help since after Rxe5 the knight on e7 is pinned and cannot capture the white queen.
> 4 votes

# Answer
After Nf5 ...Qh7??, Nd6+ wins the queen.
> 3 votes

---
Tags: learning, strategy, stockfish
---


# Question
Title: Is it beneficial to play themed practice games?
While practicing, is it advisable to play themed games? For example, playing practice games using the Sicilian Defence, or the French Defence.

I play at an intermediate level. I have chess.com rating of around 1500. I have never read or studied any chess books.

# Answer
> 1 votes
For somebody at your level I'd recommend to focus on tactics and general principles (in openings/middle game and endgames) first, before worrying about specific openings (which have very little effect compared to missing simple tactics etc). Also if you learn typical general motives/principles of openings (attacking a pawn chain, developing pieces....) first they will help a lot when studying a particular opening later.

If you do want to learn an opening, I would recommend to first find out what kind of player you are, particularly whether you prefer closed positional games or rather open tactical battles. This will influence the kind of opening you are happy with.

In a second step, I'd take a look at some master games played in different openings and see what kind of positions result from different openings and which of them you like best. Looking around moves 10-15 is usually a good indication for what you get out of the openings.

If you have decided on an opening I'd start with learning the main line to some reasonable depth. Make sure not only to memorize the moves by heart but also to understand why they are made and what the general idea behind this particular opening is. For this you probably need some external help such as books, a database and online resources (videos, streams where good players comment on their moves live,...).

Once you have a rough idea of how this opening works you can think of playing themed games with an opponent. This will be a lot more efficient if your opponent has a much higher level than you or at least knows this opening much better than you; as in that case he will be able to point out mistakes you do when practicing. BTW, on lichess there are also regularly themed tournaments where you start from a custom position (randomly playing black and white): https://en.lichess.org/tournament

In any case I'd see these themed games only as a supplement and a way to test yourself. If you want to be serious about chess, it will not replace studying with databases, books, annotated games, analyzing your games for mistakes etc. Another good way to study particularly if you reach a level of Elo 2000 or so, is to pick a GM who is playing your opening and to follow their games.

# Answer
> 7 votes
It really depends on what your end goal is. Themed games in a specific opening are good to get familiar with a specific opening, and get a "feel" for the positions arising in the resulting middlegames. So, if you want to learn a new opening, or are having trouble in a certain line, it could be a great way to learn an opening, coupled with studying some opening theory (on the 1500 level the amount of opening theory needed isn't that great, and a few lines together with some basic knowledge of ideas in the opening usually is enough).

However, if you want to become a stronger player all-round, I would say that it's an inefficient training method in and of itself, and should be used as a supplement, rather than your main means of exercise. You will learn more studying tactics and analysing your games, since tactics will be an area any 1500-level player can improve, and practicing analysis is key to being able to improve later on. But of course - play chess! That is probably the single most important means of training available, since it gives you more experience. And playing some of these games in a pre-arranged opening line will not be a waste.

# Answer
> 6 votes
A great practice routine if you have a willing partner is to take a position from an opening you wish to study and play a series of blitz games from both sides. For example, when I was younger me and my chess buds would play a bunch of blitz games from B63, Sicilian Richter-Rauzer position:

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6 7. Qd2

We did this with the Sicilian Dragon variation as well.

This is a tremendously beneficial training technique. You learn what types of middlegame plans work (and don't work) from both sides of the board. Pick any opening position , say 6-10 moves in, and have at it.

After you have played a bunch of blitz, move along to longer time controls (G10, G15, G30 even), and help refine your play.

# Answer
> 0 votes
I think it can be very good especially if you are getting into a rut playing the same sort of game over and over again. I know that when I played too much blitz I just threw openings all over the place, but I wasn't focusing on one and learning. It became more about short term trying to fool my opponent than saying, I want to get better at this or that.

So if you see yourself or a friend flagging in this way, a training game seems like a good way to get around that. Keep notation and see what computers/books say and it'd be a very good learning experience.

---
Tags: opening, training, best-practice, preparation
---


# Question
Title: Are chess engines too briliant to play good endgame?
I watched some Komodo endgame play and what he is capable of is just horrible. From nice advantage with pawn up and activity he gives up two pawns ending in some miracle fortress position. Who can blame him when he knows everything about the endgame (7 man position for example using 6man tablebase) in a few seconds, knowing it is 0.00 everywhere, but still, is this the best chess engines can do with technical endgames? I see no imagination in his endgame play, no problem creation for oponent, just random moves not making his position worse in theoretic terms. Clearly he would lose many points playing this way with any human being incapable of precise play. Playing another perfect oposition they don't lose anything but still not sure I like such a design.

As far as I understnad engines, contempt has nothing to do with this problem, is there another setting that can help here?

Edit: example position

```
2k5/7R/r5p1/3K4/3P4/7P/8/8 b - - 0 1

1...g5 2.Ke4 Kd8 3.Ke5 Ra3 4.Rh6 Ke7 5.Rh8 Re3+ 6.Kd5 Kf6 7.Kc5 Kg7 8.Rh5 Kg6 9.Rh8 Kg7 10.Rb8 Rxh3 11.Rb2 g4 12.Rg2 g3 13.d5 Kf6 14.d6 Ke6 15.d7 *

```

# Answer
The problem with an engine playing a drawn position with tablebases is that it has no concept of making life difficult for the opponent. All their moves are perfect in the sense that they don't turn a drawing position into a losing one -- not losing is guaranteed. But it has no concept of trying to win, and no way to decide between several moves that all lead to yet another drawn position, because in theory there *is* no difference.

If you turn off the tablebases, you get the normal engine play. It won't be *perfect*, but still usually much better than humans, and it uses an evaluation function that rewards material advantage, passed pawns, active pieces, and so on. That's probably what you want.
> 6 votes

# Answer
I think @RemocoGerlich is correct, and I'm here to add a real-life example. The point is that a chess engine would like to transpose a position into a known endgame.

There is also a technical explanation from Syzygy's author in the reference (nobody understands tablebase better than him!).

> Reference: http://talkchess.com/forum/viewtopic.php?t=62837

Although black easily wins in the following position, Stockfish with 6-piece Syzygy would give the move:

> 1...Qe3+ 2.Kd5 Qxd3+

* The reported moves appear to be random and absurd, but they're correct
* Stockfish would try to transpose to a known tablebase endgame as quickly as possible. While it does that, it'd play non-human moves
* If you turn tablebase off, Stockfish would do something else such as trying to checkmate the White king with the queen. Stockfish would play 1...Qc5 without tablebase, and that's also how a human would do.
> 6 votes

---
Tags: engines, endgame
---


# Question
Title: Why does White fianchetto the light square Bishop in QID
The line for **Queen's Indian Defence** goes like this -

```
[FEN ""]
1. d4 Nf6 2. c4 e6 3. Nf3 b6

```

Now, the most popular choice for white in this position is **g3** preparing to fianchetto its light squared Bishop. After this, if Black wants to develop its light squared Bishop, the two choices are either **Ba6**(modern main line) or **Bb7**(old min line). Suppose Bb7 is played by Black. Now white can also fianchetto its Bishop and the play can go on. But here is my question - Given that Black plays b6, why does white go on with g3 ? Given that white's main light squares defender around the king (after white castles king side) is its Bishop on g2 which at some point in the game can be exchanged with Black's bishop on b7, isn't this line a bit more riskier?

However, this line has been played at top level a very large number of times. Like yesterday in Tata steel 2017 masters, Aronian played this opening and won a wonderful game. So what is the justification behind white's fianchettoing its light squared Bishop given Black has already done that?

# Answer
> 4 votes
There are 3 reasons why White fianchettos the light square bishop:

1. White's plan is to play e4 to gain space. The bishop on g2 supports this
2. Building from point 1), white could play e3, Bd3 then e4, but that is an extra tempo spent to play e4
3. White has latent pressure on the queen-side, and may be able to play discovery or pinning tactics with a bishop on g2

# Answer
> 1 votes
> Given that white's main light squares defender around the king (after white castles king side) is its Bishop on g2 which at some point in the game can be exchanged with Black's bishop on b7, isn't this line a bit more riskier?

If they get exchanged black will also lose his light squared bishop which could have taken advantage of the weakened light squares around the white king. For white it would be much worse to exchange the bishop on g2 for a black knight which could make that bishop on b7 very strong.

In any case there is nothing wrong having such opposing bishops. Many other factors play a role here as well and the white bishop on g2 does put some pressure on the center and is not threatened to be immediately exchanged. You really need to look at the whole position not at one element only.

Otherwise you could argue that any opening where you fianchetto the bishop and castle to the same side (King's Indian, Grünfeld, ....) is bad as the opponent could always fianchetto himself to oppose your bishop.

# Answer
> 0 votes
The reason is the opposition of influence in the center and the common break of e4 by White. Black's q-side fianchetto by b6/Bb7 met by g3/Bg2 is common and for good reason. White wants to oppose the Bb7 with his bishop on the same diagonal, and in turn try to get in the break e4. With c4/d4 played, White will likely go for a queenside assault, perhaps down the c-file. With the b6/Bb7 being played, the fianchetto by white makes the white Kingside more secure and contests the long diagonal.

---
Tags: opening, queens-indian
---


# Question
Title: Why does FIDE rate women in different category?
Has FIDE ever given reasons why it rates woman in different category and organises their tournaments seperately?

# Answer
> 8 votes
First, let's clear up a misunderstanding. Women and men are *rated* on the same scale, with the same formula. A woman with a FIDE rating of 2400 can be assumed to be equally matched with a man with the same 2400 rating. FIDE merely defines four titles that are only available for women. In general, woman can and do participate in tournaments against men. However, there are a handful of tournaments open only to women, including a Women's World Championship.

The reason for the tournaments and titles is obvious: some women want to participate in such tournaments, and some women appreciate the titles. Chess is filled with reserved tournaments and not-too-prestigious titles of other kinds - this isn't a "woman-thing". Every club, state, or national championship is a tournament which sacrifices strength and prestige to encourage the participation of a specific group. The USCF has titles down to "4th Category", a title which requires hardly more than a heartbeat and a willingness to play in at least five tournaments, obviously to encourage tournament play among those still learning the game. FIDE correctly calculates that having the WGM, WIM, WFM, and WCM provides motivation for *some* women and encourages them to improve their game and participate in tournaments. Given that FIDE exists to promote chess among all populations, including women, providing these title is a no-brainer.

Damning women who participate in such tournaments or accept such titles is as ridiculous as complaining that the Canadian National Championship is tainted by the lack of Americans in the field or considering the USCF Candidate Master title to be a farce because it is easier to obtain than the FIDE Candidate Master. There is no shame or fraud in competing for these titles, as the requirements are well-known and observers can easily understand exactly how much prestige should be attached to them. Some of the strongest women players may disdain the women-only titles, but there are many male GMs who disdained their IM or FM norms. You may choose to learn what you want from their examples.

# Answer
> -2 votes
Chess is not a sport that relies on physical skill, not withstanding the rigors of tournament and match play. Men and Women should not be separated on the FIDE title scales. Separate tournaments? Maybe - that is the organizers prerogative. World Championship? Yes. Titles, no. This is False Prestige.

After watching the Women's Championship from (Spain?) last month and the horrid play by a supposed FIM making horrendous errors, I have no faith any of them. You are either an IM or you are not.

The Polgar(s) got it right when they refused to accept watered-down, female FIDE titles. There should be no difference, especially in this day and age where the average woman will hardly blink at telling you how smart she is and wants equal pay for equal play. I say, prove it.

Chess should award titles equally across both genders on the same scale and not discriminate women any longer.

---
Tags: women
---


title: 6 man syzygy tablebase and ramdisk

text:
# Question
Title: 6 man syzygy tablebase and ramdisk
I have downloaded a copy of the 6 man Syzygy tablebase and configured it on my Fritz 15 GUI.

Due to obvious memory constraints, the full 6 man Syzygy tablebase cannot be loaded into memory (ie. ramdisk). Will I gain any benefit moving some of the 6 piece tablebase files onto a ramdisk, and if so, which piece combinations should I gain the most benefit from (ie. in terms of endgame positions). Has anyone done analysis in this area?

Currently I host my 6 piece Syzygy tablebase on my Synology NAS via iSCSI.

# Answer
> 2 votes
I have been doing this a lot recently. My iOS Syzygy 6-men apps require at least 2GB (possibly more) to run, which is not so easy for iPhones and iPads.

* You gain the most benefit if you follow https://shop.chessbase.com/en/products/endspiel\_turbo\_4. This is also how I distribute.
* Stockfish only memory map (mmap) your tablebase file when it is needed. So you might choose your files depend on what position you want.
* I can't comment on iSCSI, NAS etc.

# Answer
> 1 votes
During search engines access the \*.rtbw files only. These are best placed on your fastest local drive (ca. 70 GB). Low latency is more important than bandwidth.

The \*.rtbz files are not speed critical. They are needed at the root only, when playing out 6-man positions.

The caching is best left to your OS.

---
Tags: engines, tablebases
---


# Question
Title: Endgames: How was "maximum moves required" determined before tablebases?
To use a simple example, tablebases show that KQ vs. K is won in at most ten moves. But chess books going back many decades, well before tablebases, say the same thing. How was this calculated?

# Answer
> 5 votes
Nothing was calculated. They arrived at their results by trial and error.

Some guy would start with a seemingly disadvantageous position and tried to find the shortest mate. His result remained valid until the next guy found a more disadvantageous position or a quicker mate.

A long time later, engines became powerful enough to calculate simple endgames like K+Q v K simply by exhausting all possibilities, but by that time technology was also advanced enough to create the first tablebases.

# Answer
> 1 votes
Well, it *is* calculated by tablebases. I can't imagine anybody declaring a definitive number for the minimum moves needed to achieve checkmate with KQ vs. K.

---
Tags: endgame, calculation, mathematics
---


title: What do top players' get from coaches?

text:
# Question
Title: What do top players' get from coaches?
I read an article about how Wesley So hired a coach. Well, Wesley is rated 2800 and is far stronger than his coach ever was. I'm just wondering what a coach would have to offer to a player as strong as Wesley, and if it's really worth the money.

In physical sports, coaches can provide plans. For example, in tennis, Nadal is a great player. His coach can give him plans so that Nadal can go out and execute them. The reason Nadal is better than his coach is because he can execute the plan.

But, in chess, the plan is the sport. If Wesley So's coach can make better plans than Wesley So, why isn't he a better player than Wesley ?

# Answer
Being a good coach takes a different set of skills than being a great, or world-class player. You can't just say that the coach makes better plans, as that is over simplification and somewhat inaccurate. The point of the coach is typically to help the player identify and eliminate their weaknesses, whether it's tactics, strategy/positional considerations, technique, opening, middlegame, endgame, etc, or non-chess considerations like diet and exercise. The coach will also have different ideas on how a position could be played, and can be useful in bouncing ideas around with, or analyzing opponents weaknesses.
> 6 votes

# Answer
Everybody needs training material, preferably specific to the skill to be trained.

You and I can just buy improvement books with hundreds of positions and have plenty work to do, at a high enough level. And we have so many weaknesses in our play that basically any training helps.

When you're a professional grandmaster, you've already done all the books when you were 14. You spend 10+ hours per day improving your chess.

Much material presents itself (you need to analyze your own games and those of the other top players to death, keep analyzing all your openings to find new ideas), but someone also has to collect interesting training material to improve your skills, and that can be a full time job. They need to be good enough to know what kinds of position a player with some set of strengths and weaknesses (even a 2800 player) needs to get better.
> 1 votes

# Answer
Well, same argument could be made for all the other top athletes in different individual sports. Why does Roger Federer needs a coach? Why did Michael Phelps need a coach? Whether is to point them to the right direction, give them study plans, analize their or an upcoming opponent's strategies, boost their mental skills (a huge part in individual sports, can't stress this enough), the fact is all top chess players have coaches. Just because they are good, they aren't perfect. So they all have room for improvement, that's why the coach(es) exist.
> 0 votes

# Answer
> in chess, the plan is the sport.

You seem to be confusing "training plan" with "strategic plan". The coach's job is to diagnose weaknesses and strengths, and design a corrective *training* plan with exercises and study to address the weaknesses. It is also his job to help develop a playing style that will exploit the player's strengths and minimize the impact of their weaknesses.

This has nothing to do with the actual conduct of a particular game, which is where a *strategic* plan is used.

I will assume that, with this point clarified, it is straightforward to see how a coach can be better at developing a training plan than the player himself.
> 0 votes

# Answer
I think making plans and executing them are two different things. Our calculational abilities diminish as we get older, so maybe having someone who can work out the big picture stuff but is not able to calculate as far ahead could be very valuable.

In addition a chess coach may not want or need the thrill of competition any more. For instance, Garry Kasparov retired as world champion and coached Carlsen for a bit, but then Kasparov found activism to be where he wanted to focus his energy. Other coaches may have a family that means they can't focus on chess full-time. Kasparov is still very good at chess if he wants to be. But he did all he could and decided to move on.
> -1 votes

---
Tags: psychology
---


title: what does this move achieve?

text:
# Question
Title: what does this move achieve?
I was watching the current Carlsen vs Adhiban game and I saw a move that always puzzles me:

```
5. h3 Bh5

```

I'd say Carlsen want to unpin the knight, or kick the bishop away. The bishop retreats, while keeping pressure on the same diagonal

```
6. Be2

```

This move I don't get. I can imagine that `6.g4` would cause positional trouble on the kingside, so the bishop is moved to e2 in order to break the pin.

But if this is true, then why did Carlsen play `5.h3` in the first place ?

I don't get what does `5.h3` achieve.

Thanks !

# Answer
I see at least 3 good points to `5. h3`:

* first and foremost, it puts a question to the Bishop: if Black wants to maintain the pin, he will have to move it to `h5`, which is more vulnerable and decentralized. Moreover, once the Bishop will be on `h5`, white squares on the Queenside will become vulnerable, as the Bishop cannot retreat and defend them in one move (just have a look to `b7`, for example);
* once the Bishop is on `h5`, White can kick it away with `g4` if he wants, gaining space and advancing a Pawn with tempo;
* now that `h3` is in place, `h2` becomes a comfortable flight square for the King if White castles Kingside, thus avoiding first rank weaknesses during the endgame.
> 4 votes

# Answer
I would emphasize and simplify @javatutorial's 1st point: 5 h3 restricts the bishop's mobility.

It used to have freedom to transfer between the kingside and the queenside, but now it cannot reach the queenside during the opening unless it can reach f5 or e4, which is very unusual. This reduction in the bishop's scope makes it less powerful than it was before, and therefore *worse*.

So, the main point is to make the bishop *a worse minor piece*, which is a strategic goal for White in this opening.
> 3 votes

# Answer
Off the dome:

To support a future g4/h4/h5 push; Protect against Nf6-g4; forces the bishop to a more vulnerable square (h5; make Black make a decision regarding the bishop - exchange it/leave it on the c8-h3 diagonal/move it to h5.
> 1 votes

---
Tags: analysis
---


# Question
Title: Why do houdini and stockfish give this seemingly stupid move?
```
[fen "3r3k/1rp2p1p/4b2B/p3P1Q1/3q4/1P1P2P1/P4PBP/1R4K1 b - - 0 28"]

```

They both give Qxf2 as the best move. I used http://analysis.cpuchess.com/ with search time 10 seconds. It's black to move.

# Answer
> 13 votes
In the given position, Black ultimately has no way to avoid an impending checkmate, hence is lost no matter what. The engines you're consulting are just trying to push that unavoidable mate as far into the future as possible. `1...Qxf2+` does that the best; any other defensive tries lead to a quicker checkmate. For instance:

```
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[FEN "3r3k/1rp2p1p/4b2B/p3P1Q1/3q4/1P1P2P1/P4PBP/1R4K1 b - - 0 28"]

1...Qxf2+
    ( 1...Rg8 2.Qf6+ Rg7 3.Qxg7# )
    ( 1...Qxe5 2.Qxd8# )
2.Kxf2 Rg8 3.Qf6+ Rg7 4.Qxg7# *

```

# Answer
> 2 votes
Let me explain what Black can do in this position first, eventually you will understand why Qxf2 isn't the stupidest move which engines are saying.

I want you to see this as a real war and you are the black King here (\*not at all being racist! :p )

So anyway, in the battle your opponent's Queen and Bishop's combined force is about to kill you in 2 days, 1st day the Queen invades your g7 kingdom and threatens to kill you on h8 on the 2nd day. As you can not escape your death, you wish to live longer at least! Hence the Engines you possess to help you survive are suggesting the best ways for you to live longer, the engines, as they are robots, they are not sensitive for your feelings of love and lust towards your Black Queen(\*again! not being racist or hurting your feelings) and hence says you to send your queen to f2 on the first day so that your opponent's King has to deal with your Queen first before killing you and so you can live longer. I hope you have understood by now, but if not;

In pure chess language:

You are getting mated on g7, you can defend the g7 square by playing 1..Rg8, but 2.Qf6+ will be a forced mate. If 1...Qxe5, then 2.Qxg7 Mate. Hence only 1...Qxf2 will help you prolong the mate by 1 additional move, and that's why computer suggests that as better than anything else.

```
[FEN "3r3k/1rp2p1p/4b2B/p3P1Q1/3q4/1P1P2P1/P4PBP/1R4K1 b - - 0 28"]

1...Qxf2+
    ( 1...Rg8 2.Qf6+ Rg7 3.Qxg7# )
    ( 1...Qxe5 2.Qxd8# )
2.Kxf2 Rg8 3.Qf6+ Rg7 4.Qxg7#

```

So, sensibly, you can resign in this position if you want to even before Qxf2. But technically, Engines are programmed in such a way that it goes as deep as possible in search of finding the best moves, and here it found Qxf2 that took it the farthest.

# Answer
> -2 votes
Simply put, ...Qxf2 is a *"spite check"*, otherwise known as a *"nuisance check"*. It serves no useful purpose other than to delay the inevitable and frustrate the opponent.

---
Tags: analysis
---


title: Why is Kf8 the recommended move here?

text:
# Question
Title: Why is Kf8 the recommended move here?
in this position:

```
[FEN "rnbqk2r/pp2bppp/5n2/1Bpp4/8/3P1N2/PPP1QPPP/RNB1K2R b KQkq - 3 7"]

```

Stockfish 8 gives the move of Kf8, and claims my move of Bd7 is an inaccuracy. I don't quite understand why. I can see that it breaks the pin on my bishop on e7 and sets up for possible tactics with Qa5, but that's not going to happen against decent opposition and surely I'd rather my right to castle and connected rooks rather than my rook doing nothing on h8 and a somewhat weakened king.

Maybe this is just one of those positions where an engine gives moves too removed from human play to really comprehend?

Any help is appreciated, cheers.

# Answer
> sets up for possible tactics with Qa5, but that's not going to happen against decent opposition

Well, the Qa5+ tactics is *exactly* what's going to happen, and Black also threatens ...a6, ...b5 and ...c4 trapping the Bishop. It looks like White cannot avoid losing a piece, but he will only get a pawn and some light pressure in return.

```
[FEN "rnbqk2r/pp2bppp/5n2/1Bpp4/8/3P1N2/PPP1QPPP/RNB1K2R b KQkq - 3 7"]

1... Kf8 2. Ba4 {2. a4 doesn't help because of ...a6, trapping the bishop; 2. Nc3 fails to ...d4 and the bishop will again be unprotected} Qa5 3. Nc3 d4 4. O-O dxc3 5. Re1 Qd8 6. bxc3

```
> 10 votes

---
Tags: analysis, stockfish
---


# Question
Title: Is there a copy of Troitsky's analysis of KNN vs. KP online anywhere?
This is almost certainly public domain material by now (I believe it originates in a 1906 article), but I'm happy to buy it with or without *Collection of Chess Studies* if I can get it as a digital download somewhere.

Nunn defers to the original analysis because of how accurate it was. The derivative material on this endgame from other authors leaves too much unanswered for a more complete understanding (the original analysis contains dozens of pages).

# Answer
> 4 votes
Troitsky's analysis of the endgame K+NN v K+P was published in the German magazine *Deutsche Schachzeitung* in 19 installments between 1906 and 1910. They all can be read online. I am not aware of an English translation. A Russian book featuring his full analysis was published during Troitsky's lifetime. Apart from that, I don't know of any other source.

Permalinks of the five relevant *Deutsche Schachzeitung* volumes follow below. In case that I missed an installment, serve yourself in the TOC at the beginning of each volume.

To access the full text you need to connect from a US IP address. If you are located elsewhere, use a VPN and set the USA as your country of origin.

---
Tags: analysis, endgame, theory, books, knight-endgame
---


title: How to start arena on Ubuntu linux

text:
# Question
Title: How to start arena on Ubuntu linux
I would like to be able to play the Stockfish engine using the Arena GUI. I consulted the "playarena" site and the only instructions were to download and unpack the .tar.gz file. I did this but there is no makefile in the directory so I am not able to compile the Arena application with a 'make' command. what steps should I take to get Arena working with the Stockfish engine? I am new to linux and would appreciate any help. Thank you.

# Answer
Arena is not an open source program, so you won't be able to compile the source code.

Do you see `Arena_x86_64_linux`? Just run it and play chess.
> 0 votes

---
Tags: engines, linux
---


# Question
Title: Mathematical formula to get how broad opening repertoire is
programmers and mathematicians!

I'm looking for some opinions how to build meaningfull formula that represents broadness of opponent's repertoire.

At the moment I do it like this:

1. I filter all positions that player played at least 2 times. This count = **N**.
2. By Monte Carlo I evaluate average "broadness" of Mr. Average (using book informations about move probabilities) for **N** occurrences in his games.
3. I evaluate the same "broadness" for our target player.

This broadness I calculate with "pythagoras thesis" sqrt(m1^2+m2^2+m3^2+m4^2 + ... + mn^2)/N where m1 is number of occurrences of move 1, m2 occurrence of move 2 in that position and sum(m1...mx)=**N**

So if in 20 games you play 20 times 1.e4, you get sqrt(20^2)/20=1 which means the extreme when repertoire is just as narrow as possible.

When you play 10x 1.e4, 8x 1.d4 1x 1.c4 and 1x 1.Nf3, you get sqrt(10^2+8^2+1^2+1^2)/20=0.64420493633

And when you are on the other side of extreme and make 20x different move in starting position, you get sqrt(20)/20=0.22360679775.

Now I can sum broadness of Mr. Average to find the optimum. I can do the same to the target player and find how the numbers compare to the strategy that I call optimal (playing book moves as Mr. Average). I can weight position broadnesses by any f(N). I can divide player/mr. Average at every position or I can divide sums of these values, there is milions of approaches that can be used but none of them seems easy and logical at the same time.

I'm not concerned here about using correct moves, as I deal with them in other formula. So if it is 10x a4, 8xNh3 etc, I don't mind having same number here like for 10x e4, 8x d4...

With my approach it is possible to see difference between players playing always the same positions compared to coffeehouse masters just picking the line randomly, but still

1. I don't see much logic in my calculation in the first place.
2. The numbers aren't distribured very nicely
3. With changing amount of games/positions same number might have different meaning.
4. I worry there can be problem that the final result can be created by one huge number making the rest of calculation irrelevant.

The only thing I really like here is comparing to Mr. Average, as I don't want to blame players not to be creative in positions where only one move is serious.

If you have some ideas, link to mathematics page dealing with similar problem, anything, I will be happy to think about it!

# Answer
I don't believe your approach works because you're counting every position as an opening repertiore what you're actually measuring is the degree to which they play openings where theory has prescribed a large number of moves. For example, a Ruy Lopez player might play the first 15 and 20 moves to reach the end of book play. In contrast, someone who plays the Trompowsky or another unusual opening might be out of book after six moves. Therefore, I would define "opening" differently. For example, you could use ECO standard positions as a starting point for defining a person's opening. I believe Eric Schiller also has an list of chess openings.
> 3 votes

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Tags: opening, programming, mathematics
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# Question
Title: I heard professional chessplayers must train physically as well as mentally. Why is that?
I heard that both Fischer and Karpov felt that physical training was extremely important to their success and that the Russian coaches also felt a certain amount of physical training was necessary. Why is that? How is it supposed to help? What sort of exercise is supposed to help.

# Answer
You've heard it right. Physical training is as important as mental training in chess. Thinking is an energy intensive activity and often has a direct effect on the physical body. Quoting this scientific american article by By Ferris Jabr on July 18, 2012, *brain weighs about 1.4 kilograms, only 2 percent of total body weight, it demands 20 percent of our resting metabolic rate (RMR)—the total amount of energy our bodies expend in one very lazy day of no activity*.

Karpov had lost 10kg (22lb) over the course of 1984-85 Kasparov-Karpov world championship match. Quoting Kasparov from this interview, *I pay a lot of attention to my physical condition; to be fit under the terrible pressure of big competitions. Obviously this is becoming more important with age*.

From a study by Speakman JR *et. al*, being physically fit improves resting metabolic rate (RMR) which is a major contributor to daily energy reserve and thus any increases in RMR in response to exercise interventions are potentially of great importance.

Chess, as you know is a brain intensive activity and thus RMR plays an important important role. Therefore from the 1st and the 3rd paragraphs, it is clear that physical fitness improves mental fitness and therefore beneficial to chess.
> 8 votes

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Tags: training
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title: Best ways for improving "tactics"

text:
# Question
Title: Best ways for improving "tactics"
I have been playing chess for a long time, and I have been around `1850-1900 ELO` for quite some time. I have always wondered which are the ***best ways to improve the tactics***.

* Does playing more and more games improve chess tactics?
* Playing limited games but slow games?
* Practicing board positions with sites such as chesstempo?
* Analyzing others' and self games

Please feel free suggest any point that I have not covered.

# Answer
> 15 votes
All of the suggested can improve your tactics skills. Anything that makes you think hard about chess positions (particularly sharp and complex ones) will. I would add "perfecting the way you calculate variations", i.e. making sure that your calculation is as effective as possible. This was well described in some book, I think it was "Think like a grandmaster" by Kotov. Two points though:

1. Chess is not only tactics, the strategy, "feeling" for positions, is equally important. And one should always come with the other. In fact they make each other better.
2. Judging from your Elo, you are a hobby player. Getting better may need hard work which does not always agree with the word "hobby", so pick the method that you enjoy and keep in mind that everyone has limits.

# Answer
> 6 votes
Best trainer I've ever seen for tactics: CT-ART. Full stop. It's relatively cheap ($20US, give or take) and walks you through thousands of tactical positions, showing you all sorts of techniques, and relentlessly drilling you in them. I'm a Mac user, and I keep parallels around mainly for this program.

To start out with it, I'd put it in test mode for 15 positions or so. If you get lost trying to figure it out, step over to practice, or even theory for a while, but you'll get the max benefit from it with test, because then it just shows you the position, tells you who is to move, and the rest is up to you; no hints until you make mistakes.

# Answer
> 5 votes
At your level, you should be thinking in terms of combinations, or *chains* of moves. Beginners learn the basics, pins, forks and skewers, but you are a bit past that. Instead, you might be thinking in terms of preparatory moves that set up these tactics. That takes a bit more doing, but is a mark of advanced play.

# Answer
> 3 votes
Tactics, calculation, dynamic play. Topics often talked about but seldomly understood at their very depth. I cannot claim to cover the whole subject in this post. Yet hopefully I will scratch the surface of this vast subject. To become stronger in dynamic play, you need to understand the ingredients of dynamic play. There are at least two parts, calculation and vision. Calculation is the ability to enter different variations in your head and find the best moves for yourself and the opponent until you reach a position that you think you can evaluate. Vision is the ability to find ideas which in turn show you what moves or series of moves that are important to check.

Dynamic play is improved by training the calculation and vision skills. It is recommended to follow a calculation technique (as described in some books, e.g. Kotov) when calculating variations. By learning and applying the technique on a regular basis, your calculation will improve accordingly. Training your vision is more complex. You may have heard of patterns and that our brains memorize patterns when playing through grandmaster games and then we are able to apply these patterns in our own games. This most probably holds true. You should also collect ideas by reading annotated games and paying attention to the ideas that were described in these games. The ideas will also become patterns that you can apply in your own games.

Training correctly and truthfully is very hard. Training will give results. The best way to improve your dynamic play (I don't really like the term tactics because it somehow makes it sound more simple) is to train hard. To follow the training system that your books actually recommend. To get a personal trainer and/or mentor. To take every game seriously. To work hard at the board in each game. To analyze your games afterwards. To be self critical after every loss, draw and win. Dynamic play is a big part of every game. You have the static part and the dynamic part. So the dynamic play is at least half of every game. That being said, even 15 minutes a day will give great results, as long as you train properly. Happy hunting!

# Answer
> 2 votes
In addition to the above answers I would recommend using `Computer Chess Programs` for improving tactics. While playing with humans you sometimes get a false `high` when an incomplete attack results in success (usually in the form of material gained). A decent computer program will rarely fall for immature tactics, thus providing a strong incentive to be thorough with your attack preparations.

# Answer
> 0 votes
Bondarevsky, in the good old classic "Combinations in the middle game" recommends building a catalog of combinations classifying them for topic, resultant attack, motives, etc. He also recommends studying games of heavy tactical content.

# Answer
> 0 votes
Try Here and just do the daily tactics. you are only allowed 3 a day for a free account but if you upgrade your account you have unlimited. You could also invest in a tactics book.

# Answer
> 0 votes
Calculation is often improved by practicing more and more, and analyzing your thought process. This helps understand the decision making process you use to come up with a solution. Together with chunks, or knowledge about patterns, a player would become better at his calculation. In order to train this skill, one might either use chess books like Anthology of Chess combinations, or free chess tactics trainers like Chessity, which is quite fun to solve.

# Answer
> 0 votes
I had your rating. I read "Think Like A Grandmaster" by Kotov and practiced the techniques for 6 months. I played in a few tournaments and I skipped the expert class gaining 250 rating points and became a master but that was a long a time ago in the 70s. I don't know if it would work today.

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Tags: learning, tactics, training, calculation, best-practice
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