# Question
Title: Should one actively search for a checkmate ('hunt the King') in the middlegame?
My usual middlegame strategy is to gain an advantage, however small (say a pawn), and convert it to a win in the endgame. I position my pieces and plan attacks accordingly, so that I can grab the small advantage I need. I don't actively hunt for the opponent's king, and prefer to first gain an advantage, so I can exchange pieces and win. So the entire game grinds on.

That said, I don't (usually) miss a checkmate if my opponent blunders in the middlegame. On the whole, though, I prefer taking the game to the endgame, even if my advantage is significant (~3 points).

However, I've seen players who actively attack the king in the middlegame itself. They position their pieces in such a manner that they threaten checkmate, and seem to plan to finish up the game in the middlegame. They try to take advantage of the castled king's reduced mobility, and checkmate him. The success of this strategy depends, it seems (based on what I've seen), on both the opponent's skill level as well as on luck.

### My question

I wonder, as a **general rule**, what should one's middlegame strategy be: should one actively *hunt* the opponent's king in the middlegame itself, looking for a checkmate, or try to gain an advantage which can be converted to a victory later?

# Answer
> 5 votes
There is no overarching middlegame strategy that trumps all other strategies.

Both middlegame strategies listed are viable general strategies to play for, **if the position allows it**. What makes a difference are your own preferences; if you love tactics and mating attacks then you should probably go for middlegame positions that allow you to play in that manner, and similarly if you like calmer positions you should probably go for positions that aren't as sharp. Objectively speaking there isn't really much saying that one playing style is better than the other.

# Answer
> 3 votes
As Scounged mentioned, there is indeed no specific strategy that trumps all others.

However, note that the middle game can be seen as the tipping point of the game. It is usually what defines who wins the game in the end. My playstyle would be to balance both attack and defense, but ultimately, it is based on preference, when it comes to positions that seem equal.

# Answer
> 2 votes
There is no general rule. Most of the time, the middlegame strategy will depend on the position you get out of the opening. Personal preferences can play a role as well, but typically players would pick an opening based on their preference for a certain middlegame (which results from that particular opening). It is not a good idea trying to force your preference onto any position you get.

For instance in open positions it is often not a good idea to force a pawn storm on the enemy king. Conversely in very wild position piece activity and attacking things might be more important than calm quiet play or perhaps winning a pawn somewhere.

Of course, if the position allows for various playing styles, you would go with whatever you are more comfortable with. However actually checkmating rarely happens in the middlegame (of games between reasonably advanced players).

# Answer
> 2 votes
To say that choosing to attack the King should be based on personal style or the nature of the position is certainly true but not all that helpful.

The best book on this is the Art of Attack in Chess by Vukojic. He explains what he calls the preconditions for the attack. Presence of attackers, absence of defenders, mobility, weak points...

These things need to be in place before the attack happens. The player with a taste for attack must first bring about the preconditions, and if they cannot do so, they should not attack. They should not even persist in trying to create the preconditions. Play through some of the games where Tal decided not to attack and ask why not.

---
Tags: strategy, checkmate, middlegame
---


# Question
Title: Specific for Lasker during 1904 Cambridge Springs tournament
I have heard that Emanuel Lasker, during the great historical tournament in 1904 (in Cambridge Springs), had to face some specific which was imposed on him. I am wondering what could be meant by that? Was there any kind of handicap with which he had to deal with?

Most of the sources I could find on the internet do not mention any kind of special specific for Lasker.

# Answer
From 1902 to 1907 Emanuel Lasker was living in the USA and concentrating more on algebra than on chess. His paper Zur Theorie der Moduln und Ideale was published in March 1905 in *Mathematische Annalen* and will lead to the famous Noether-Lasker theorem.

*It seems he also worked on some papers in the field of philosophy, but I know less about it.*

Chess was not his main preoccupation during those years, and his participation in Cambridge Springs tournament in 1904 was a short chess parenthesis in his mathematical works.

There is no indication that Lasker was playing with any handicap in that tournament, beside lack of practice and training, and this seems very unplausible to me.

A few years later, Lasker will go back to "wasting his wonderful mind" on chess, according to a famous Einstein's quote that may be less apocryphical than most Einstein's quotes.
> 2 votes

# Answer
The only specific about Lasker and Cambridge Springs 1904 I found is the fact that he practically didn't play serious chess for about 4 years (last tournament Paris 1900 which he won with unbelievable 14,5 pints out of 16 and in 1901 and 1903 four games in sum against Janovski and Chigorin....). This missing practice was probably the reason why he lost two games in the early phase of the Cambridge Springs tournament (see also https://kevinspraggettonchess.wordpress.com/2011/04/12/tidbits-on-cambridge-springs-1904/ ).
> 1 votes

# Answer
I flipped through part 1 of Kasparov's Great Predecessors book (which covers the lives and games of Steinitz to Alekhine) but couldn't find anything on a handicap Lasker faced in Cambridge. All I could find was that he lost to Pillsbury, who was declining but managed to make a short comeback.

Maybe Lasker had something going on in his personal life or issues with travel internationally. Back then, if another player managed to evenly challenge the world champion in chess (Lasker at the time), a match for the title tended to follow. Lasker could have been experiencing pressure and a need to do well in order to cement his place as the best player in the world.

Still, this is all merely speculation. If he did experience a handicap then it's odd I couldn't find it in Kasparov's book, since his series is one of the foremost authorities on chess history.
> 0 votes

---
Tags: history, lasker
---


title: Exchange in the Scotch Four Knights

text:
# Question
Title: Exchange in the Scotch Four Knights
In the main line of the Scotch Four Knights

```
[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Nxd4 Nf6 5.Nc3 Bb4 6.Nxc6 bxc6 7.Bd3

```

What's wrong with 7...Bxc3 ?

It seems this move is played very rarely, but, when I play White, I would not like to face it, because of the horrible pawn structure White gets, with isolated doubled pawns and another isolated pawn. For example, see the position after the normal moves 7...Bxc3 8.bxc3 d5 9.exd5 cxd5.

Of course I see that White gets the Bishops pair and an open b-file, and he can also play Ba3 preventing Black from castling. But is this enough to compensate for the bad pawns? Or is there something else that I don't see? What should be the plan for White after 7...Bxc3 ?

# Answer
7...Bxc3 is not that horrible, but a bit passive: anyway, you could postpone that exchange until White castles, since he probably won't dare to avoid the doubled pawns with Bd2.

However, after 7...Bxc3 8.bxc3, I don't agree that 8...d5 is "the normal continuation" at all. After 9.ed5 cd5 10.Ba3, Black won't be able to castle and faces huge difficulties. When you surrender the bishop pair, you better place your central pawns on squares the opposite colour from your remaining bishop; also, you don't want to open the game too fast.

8...0-0 is logical, avoiding all that Ba3-nonsense. 9.e5 Re8 is not to be feared, and Black will develop solidly with ...d6, ...Re8, ...c5 and ...Bb7 (or ...Bd7-c6), trying to put pressure on e4, since he has no way of attacking the weakened pawns on the queenside (a2, c2, c3).

White's plan is more active. He can support his Pe4 and prepare a breakthrough with e4-e5. His plan may go 0-0, Bg5 (in case of ...h6, go back to h4, don't exchange), Qd2 (or Qf3-g3), Rae1, f4 and e5, opening files and diagonals. Alternatively, he may engineer e4-e5 without f2-f4, with support by the bishop from f4 or g3.

Note than the Bg5-Nf6-Qd8 pin is especially annoying since Black has no dark square bishop to break it, and damaging your king's shelter with ...g7-g5 or ...gf6 is not really what you want to do.

All in all, White has a small but clear advantage, and Black has a solid but passive position.
> 2 votes

# Answer
I think you got it basically right. White gets the bishop pair which in an open position like this, is a real advantage. Also black currently does not have any good squares for his pieces. Lastly, it is difficult for black to take advantage or to attack the doubled isolated pawn.

White's dark squared bishop could go to g5 where the pin of the knight is kind of annoying or to a3 where it might hinder black from castling.

Regarding your proposed continuation, I believe that after 7...Bxc3 8.bxc3 d5, white can play 9. e5 asking the knight where it wants to go. Also after black's d5 the a3-f8 diagonal gets weak and the bishop on a3 will be really strong.
> 4 votes

---
Tags: opening
---


# Question
Title: Engine recommends a move that (I think) loses a pawn
```
[FEN "rn2kbnr/ppp1pppp/8/3q4/3P4/8/PP2PPPP/1RBQKBNR w Kkq - 0 5"]

```

If white doesn't play Ra1 then black can play Qxa2. But the engine says this is an inaccuracy, and that the best line is e2-e3.

# Answer
> 7 votes
In short: White can sacrifice the pawn on a2 and will gain a quicker development of his pieces. The technical term for this is compensation.

In detail: In the current position, both sides have not developed their pieces. Getting out the minor pieces and castling should have priority.

There are no obvious weaknesses. In some lines (e.g. if white's bishop is on f4 or g5 and e3 has been played) white should watch out for Bb4+. Also black has an easy way to simplify/equalize the position further by playing Nc6 followed by e5 or alternatively to attack the center with c5.

Because of this it is essential to **act quickly**. The white dark-squared bishop probably wants to stay on c1 or d2 for the time being because of the potential threat of Bb4+ (or even Qa5+ exchanging the queens). So the most natural development moves in the position are Nf3 or e3 (making space for the bishop on f1). Either move is decent, but e3 has the advantage that the bishop can quickly go to c4 where it attacks the queen on d5 (or a2 if black takes the pawn).

Looking at the concrete line 1. e3 Qxa2 2. Bd2, you note that white has made two development moves while black has won a pawn but the black queen is somewhat far from the action and in fact is in danger of running out of squares: white is threatening for instance Qc2, Bc4 which would win the queen). Likely black would have to make another queen move retreating the queen to d5 or e6, losing even more time for development.

---
Tags: engines, analysis
---


title: Amazon vs Chancellor endgame

text:
# Question
Title: Amazon vs Chancellor endgame
Many online sources (such as Wikipedia) state that the endgame of amazon (piece that moves like Queen and knight) and chancellor (piece that moves like rook and knight) is a draw. I did some experimenting but could not find such a position. Now Wikipedia says that a draw can be **forced** with a fortress that forces the stronger side to give perpetual check without giving such a position.

Examples of positions I've tried are (the queen represents amazon and the rook represents chancellor):

```
[Title "Centralized king"]
[FEN "8/8/8/3kr3/8/8/8/KQ6 w - - 0 1"]

1. Qb4+ Ke6 2. Qf4 {Forces the chancellor into a pin} Kd6 3. Kb2 {Waiting move, and now the king must leave the chancellor} 1-0

```

or

```
[Title "Cornered king"]
[FEN "kr6/8/8/8/8/8/8/KQ6 w - - 0 1"]

1. Qe4+ Ka7 (1... Rb7 2. Qe8+ Ka7 3. Qc6+ Ka8 4. Qc8+ Rb8 5. Qc7#) 2. Qc5+ Rb6 (2... Ka8 3. Qc7#) 3. Ka2 {Any king move is followed by Qxb6#} 1-0

```

or

```
[Title "King on rim"]
[FEN "4k3/4r3/8/8/8/8/8/KQ6 w - - 0 1"]

1. Qb8+ Kf7 2. Qd6+ Kf8 3. Kb2 Kg8 4. Qxe7+ Kh8 5. Qf6#

```

All three of these examples lead to trivial wins for White. Could someone post a fortress in this endgame, if such a fortress exists at all?

---

# Answer
> 5 votes
This is a great question and a fun problem to mull over. Indeed the way it's written on wikipedia one gets the impression that amazon-vs-empress fortresses are trivial and easily attainable for the weaker side, where in fact it's very difficult to even come up with dummy examples where the empress stands any chance of holding (so not surprising not to see a example diagram there). In other word, most amazon vs empress (also known as *chancellor*) endgames are in fact winning for the side with the amazon (intuitively, the amazon has diagonal routes towards the weak points in the empress' safezone), not even requiring the assistance of the king in order to dominate the empress+king duo.

**Some intuition:** You want to have the king of the side with the amazon to be well cornered by both the empress and the king, or at least for it to be in a different quadrant of the board compared to the amazon and near the opponent king (so all cases where the amazon and the king are somewhat central is highly likely to be winning already). The reason for this setup is that it allows you to defend *certain* checks with an **empress-fork** thus forcing the draw, while covering some key squares with the empress that otherwise would be exploited by the amazon to push the king towards the center and reach a winning situation again. One of the better scenarios for the amazon side would be: to **pin** the empress while having **spare waiting** moves with their king.

*Note that in the diagram editor here the rook and queen will denote the empress and amazon respectively. Additionally, certain moves that would be illegal in standard chess thus disallowed by the diagram editor here, as we're using rook and queen instead of fairy pieces, would be mentioned in the annotations.*

It's funny, if you just try to randomly set up any amazon vs empress ending, they're *almost always* losing for the empress-side. Now even though it is still possible to find some clear setups where the empress holds, it's important to note that fortresses of this kind constitute a minute fraction of the state-space of all legal amazon vs empress endgames. This observation is well corroborated by the statistics provided here for KA vs KC (C for Chancellor/empress): If you look at the third row in that table with the percentage breakdown, only `0.001052 %` of all legal KA vs KC configurations comprise fortresses, with most other draws being by *perpetual.* The latter types of examples are simpler to showcase specially if it's the empress' side to move, whereas fortresses with the amazon side to move are highly non-trivial. Below some examples for both types of draws are showcased (annotated):

---

## **Fortress and perpetual examples:**

```
 [title "empress+king fortress example#1 - black to move"]
 [fen "k7/8/K7/6q1/R7/8/8/8 b - - 0 1"]
 [StartFlipped "0"]

 1...Kb8 {the only amazon moves either force the draw immediately or lose on the spot because of the Rb6# threat. So only attempt is to move the king and try to escape but 2.Rb6+ Kc7 3.Rb5+ forces the draw with a fork. Thus, white is holding here.}

```

Another example:

```
 [title "empress+king fortress example #2 - black to move"]
 [fen "k7/6q1/K7/1R6/8/8/8/8 b - - 0 1"]
 [StartFlipped "0"]

 1...Qa1+ {Again all key squares c7-b7-a7 are well covered, and any check on the 6th row loses immediately, so black's only other attempt is Qa1+} 2.Ra5 Qf6+ (2...Qf1+ 3.Kb6+ Kb8 {and black even gets mated here: 4.Rc6+ Ka8 5.Rc8#}) 3.Kb5+ Kb8 {and 4.Rc6+ forking and forcing the draw}

```

Now to show you how sensitive these fortresses are, let's take example#2 again with the added difference that the amazon is now in a position to pin the empress on the `f1-a6` diagonal, and that suffices to break the fortress and win:

```
 [title "Losing variation of example#2: Amazon pins can be deadly!"]
 [fen "k7/8/K7/1R6/8/8/7q/8 b - - 0 1"]
 [StartFlipped "0"]

 1...Qe2 {pinning and the Zugzwang's set: both remaining king moves are losing} 2.Ka5 (2.Kb6 Qc4+ 3.Ka6 Qa4+ 4.Ra5 Qb4#) Qc4+ 3.Ka6 Qa4+ 4.Ra5 Qb4# (1...Qa2+ 2.Ra5 {setting up a discovery on the king while covering c4} Qe6+ (2...Qe2+ 3.Kb6+ Kb8 {4.Rc6+ Kb8 5. Rc8# mate.}) 3.Kb5+ Kb8 {and the 4.Rc6+ fork forces the draw.})

```

Finally, here's one trivial perpetual example:

```
 [title "Example#3 - perpertual, empress-side to move:"]
 [fen "7q/8/6k1/8/4K3/5R2/8/8 w - - 0 1"]

 1.Rf4+ Kg7 (1...Kg5 {leads to similar perpetuals}) 2.Rf5+ Kg6 {black can avoid the repetition but only at the cost of trading the remaining pieces.} (2...Kg8 {is followed by 3.Re7+ Kf8 4.Rc8+ winning the amazon}) 3.Rf4+

```

---

## **Other variations that look tempting:**

Here's one that resembles a fortress but it probably isn't. The ideal scenario for the empress side would be something like `1...Qf8` after which the empress would try to check the king endlessly as it cannot hide behind the amazon anymore. But white doesn't have to play `1...Qf8`, instead, staying on the long diagonal with a waiting move probably wins, e.g., `1...Qf6.`

```
 [title "Example#4: other attempts worth considering"]
 [fen "8/8/8/5q2/8/2k5/1R6/K7 b - - 0 1"]
 [StartFlipped "0"]

 1...Qf8 {Any amazon check results in a fork forcing a draw, so we have to either make king moves or waiting amazon moves.} (1...Qf6 2.Kb1 {any rook move also loses on the spot, e.g. 2.Rb1+ Kc2+ 3.Ka2 Qe6+ 4.Ka1 Qa6+} Qf1+ 3.Ka2 Qc1+ 4.Ka3 Qxb2#)

```

Notice that any such pin with the king stuck in the corner is always losing, for instance:

```
 [title "Example#5: Pin exploitation to dominate the empress"]
 [fen "8/8/8/3k4/3q4/8/1R6/K7 b - - 0 1"]
 [StartFlipped "0"]

 1...Qg1+ 2.Ka2 (2.Rb1 Qa7+ 3.Kb2 Qa4+ 4.Kc1 Qa2+ {winning the empress}) Qc1+ 3.Ka3 Qa1+ 4.Ra2 Qb1+ {winning the empress}

```

---
Tags: endgame, chess-variants, fortress, unorthodox-pieces
---


# Question
Title: What is the main idea of the Morozevich variation in the French vs. the Tarrasch?
What is the main idea of the Morozevich variation in the French vs. the Tarrasch variation?

> 1.e4 e6 2.d4 d5 3.Nd2 Be7

In other words, how can Black benefit from the slightly unusual development of the Bishop before the Knight?

# Answer
`3...Be7` is mainly an attempt to side-step some of the other well-known theoretical variations, while making white to first commit another developing move before deciding how to continue. For instance, the usual `3...Nf6` often leads to `4.e5 Nfd7` and black has already committed the knight to `d7` while white has all three attractive options of `Bd3,` `f4` (further discussed in the 2nd diagram) and `Ngf3.` Instead with `3...Be7` first, many more alternatives survive, such as:

*All diagrams contain annotations.*

```
 [title "3...Be7 possible follow-ups in Tarrasch variation"]
 [fen "rnbqk1nr/ppp1bppp/4p3/3p4/3PP3/8/PPPN1PPP/R1BQKBNR w KQkq - 2 4"]

 4.Ngf3 Nf6 5.e5 Nfd7 {You see by simply having delayed Nf6 by one move and kept an option such as Nh6 open, white's choice of 4.e5 5.f4 is already less attractive} (4.e5 Nh6 {taking advantage of the early Nd2 blinding the h6 square for white so the knight can now re-route via h6-f5. This maneuver is also often employed in f4 variations of the French.} 5.Bd3 c5) (4.Bd3 c5 5.c3 cxd4 6.cxd4 dxe4 7.Nxe4 Nf6) (4.Ngf3 Nf6 5.e5 Ne4)

```

So in the above side-lines not only has black kept some additional options open with `3...Be7` but it has also made a couple of key variations less attractive for white, such the usual `f4` lines in the Tarrasch (which is also briefly touched upon on the wikipedia page of French Defense), for example:

```
 [title "classical 3...Nf6 and the f4 variation - compared to 3...Be7 :"]
 [fen "rnbqkbnr/ppp2ppp/4p3/3p4/3PP3/8/PPPN1PPP/R1BQKBNR b KQkq - 1 3"]

 3...Nf6 (3...Be7 4.e5 c5 5.c3 Nc6 {You see the difference now more clearly: 4.e5 is no longer with tempo, thus allowing black to start undermining the central pawn chain with c5 one move earlier, followed by Nc6, practically never allowing white an easy route towards the previously mentioned main variation.}) 4.e5 Nfd7 5.f4 {notice the knight's already on d7} c5 6.c3 {nothing really challenged white's f4 play}

```
> 2 votes

# Answer
I'm away from my books right now, but John Watson, in (I think) the third edition of Play The French, describes it as "a high class waiting move". You want White to commit a little bit more before deciding whether to play ...c5 (as you might after 4. e5 or 4. Bd3) or ...Nf6 (as you might after 4. Ngf3).

This is a nice game I played on the Black side.

https://chesstempo.com/gamedb/game/3500004

http://streathambrixtonchess.blogspot.com.es/2013/08/penarth-2013-last-round-drama.html
> 1 votes

---
Tags: opening, french-defense
---


# Question
Title: What are ways of practicing blindfold chess?
Is there a way to practice blindfold chess on the computer?

For example, are there any programs online which give only a transcript of the moves played, and allow you to type in your next move, rather than showing a board?

# Answer
> 10 votes
Not strictly on a computer in your sense I assume, and, depending on how good you are, potentially not challenging enough: A friend of mine did this with an old second hand chess computer. The kind that comes with a board and pieces. The board is touch sensitive to register your moves and has LEDs to indicate computer moves. He played without the pieces.

The advantage: Many of these take batteries and allow you to play anywhere.

# Answer
> 9 votes
One way to do this is to play at FICS. Using the Arena GUI - and probably others too, I'm sure (but this didn't work for me when I tried e.g. BabasChess just now) - you can login to FICS, and then enter "set style 9" in the console to set your style variable appropriately. Then just seek/play games as one normally would at FICS, and instead of the game being displayed on Arena's board, you will just be told your opponent's moves in the console, and enter your own there as well. One great thing about this is that you aren't limited to finding others who want to play blind as well, and you can switch between playing blind and playing normally as you wish by resetting the style variable.

# Answer
> 6 votes
You can do this with Chessmaster by checking `Blindfold Play` in the `Rules` Tab

# Answer
> 2 votes
You can play blindfold chess against a strong computer online at http://www.apronus.com/chess/computer.htm \- you need to tick the checkbox called "blindfold chess" and the board will become empty. The moves played will be displayed as text but the empty board is still used as the interface for making moves.

If the engine is too strong you can give it less time to think to make it weaker.

You can untick the box at any time to see the position. You can take moves back. Additionally, by clicking on a button "Chess Editor in New Window" you can transfer your game to a chess editor which allows you to export it as FEN or PGN or to make a permanent link as a bookmark or to share with other people. You can also make an animated diagram with the whole game.

Moreover, you can practice your blindfold chess starting from any set up position. For example, you may start with just the bishop and knight against a lonely king

# Answer
> 2 votes
## GNU Chess

GNU Chess works in a terminal. You enter your move, get the response. No board. Only the command line interface.

# Answer
> 1 votes
you can play blindfold on chess.com. That is a good way to practice if you are like me and dislike playing against computers.

# Answer
> 0 votes
With Tarrasch GUI you can practice blindfold, you can setup any position and play from there. I'd suggest starting with K & Q Vs K, try to mate blindfold, then K & R Vs K. Sadly its only available for windows, I haven't found a good linux equivalent yet.

---
Tags: online-chess, blindfold-chess
---


# Question
Title: Why is Black supposed to attack on the kingside in the King's Indian?
Why does the tag wiki for King's Indian say that most of Black's attacks focus on the kingside? I have found that most of my games result in play on the queenside due to my dark-squared bishop, and sometimes I gain semi-open a- and b-files for my rooks.

# Answer
> 8 votes
There is a general principle that says that, in positions with a blocked center, every side must attack in the direction where his own pawn chain points to. For example, in the KID, sometimes White has pawns in e4 and d5 (White's pawn chain) and Black has pawns in d6 and e5 (Black's pawn chain). So we see that White's pawn chain points to the queenside, while Black's pawn chain points to the kingside.

The most efficient break move hits at the base of the opponent's pawn chain. So, for example, the base of White's pawn chain is the e4 pawn, so the most efficient break move for Black is f5 (and this is a kingside attack). The base of Black's pawn chain is the d6 pawn, so the most efficient break move for White is c5 (and this is a queenside attack).

If Black does not play e5, and he plays c5 instead, the argument above does not apply, and Black's strategy changes. Even if Black plays e5 and White decides to exchange with dxe5, opening up the center, then the situation is completely different. The KID is not a one-plan opening, it is very rich, I wish I could understand it better!

Another example of the aforementioned principle is given by the French Defense, where sometimes White has pawns in d4 and e5, and Black has pawns in d5 and e6. In this case White attacks on the kingside, and Black attacks on the queenside.

# Answer
> 1 votes
I don't know if it's true that "most" games result in Black attacking the kingside. The tag claims "often", which seems to be true. For example, my openings database has over a thousand games that started like this:

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

1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7
9. Ne1 Nd7 10. Nd3 f5 *

```

Black is beginning a kingside attack here.

---
Tags: opening, kings-indian
---


title: Connecting UCI engine with iOS?

text:
# Question
Title: Connecting UCI engine with iOS?
So I'm not actually making a Chess app, but I am trying to hook up an engine that uses a protocol almost exactly the same as UCI. I can get it working quite easily on a macOS app. Now, the hard part is integrating an engine like Stockfish into an iOS app.

You can't use std input/output nor can you fork a process, so how should one manage the protocol for communicating moves to a UCI interface? I've managed to include the engine C++ library and can communicate via UCI commands in the debug console but I have no idea how to simulate std input into the engine from iOS. Should I look for hooks within the engine to call directly and simulate the game loop in Swift?

I apologize if this is the wrong community for this question, but UCI specific questions go over the head of most SO users so I thought I might try here. There are a plethora of iOS chess apps so I'm genuinely curious how people are integrating their engines into their apps.

# Answer
Simple. Inter-thread communication. Specific implementations could be:

* Internal UCI queues
* Find the UCI loop function then hook it up (e.g. UCI::loop in Stockfish).
* Redirect the standard input/output into pipes

Few points:

* It's not a good idea to do your works with Swift, because Swift has poor support for C++. I prefer Objective-C as it works with C++ at the source level.
* Redirecting is **recommended** if you're confident. All my iOS apps use that. You just need to send your UCI commands to a redirected pipe, while the engine receives them from the standard inputs (redirected). This is not a place for discussing unix programming, please ask Stackoverflow. It works.
> 2 votes

---
Tags: engines, uci
---


# Question
Title: How do engines evaluate a position (actual algorithm)?
How do chess engines actually evaluate a position? I am looking for a technical answer, not a general summary of how minimax works, I already know how minimax and alpha-beta, etc, work, so please do not reiterate generalities. I am interested specifically in the evaluation function.

My understanding is that the evaluation of a position is the same as evaluation of the leaf of the decision tree given best play by both sides. So, the problem then is how is each leaf evaluated? Obviously, whatever algorithm is used must be very fast because millions of leafs are evaluated. So, if this is right, then evaluation simply reduces to how a leaf position is evaluated.

The two methods for leaf evaluation that I know of are material balance and king safety. However, I suspect that it must be more complicated than this, otherwise evaluations would not have such fractional values. For example, there are many positions where both sides have the same material and perfectly safe kings. So, in those cases we would expect an evaluation of "0.00". However, in actuality the engine I use (Rybka) *never* has such an evaluation (unless it is a draw). It's evaluation of such positions is always something like "0.13" or "-0.05" or "0.07". So, obviously it is doing something more than just material+king safety. How does it come up with the number?

# Answer
Chess algorithms are complicated, but I'm sure static evaluation gets applied before reaching the leaf nodes. For example, it's very common to reduce or even eliminate a branch if it loses materials.

```
function middle_game_evaluation(pos) {
  var v = 0;
  v += piece_value_mg(pos) - piece_value_mg(colorflip(pos));
  v += psqt_mg(pos) - psqt_mg(colorflip(pos));
  v += imbalance_total(pos);
  v += pawns_mg(pos) - pawns_mg(colorflip(pos));
  v += pieces_mg(pos) - pieces_mg(colorflip(pos));
  v += mobility_mg(pos) - mobility_mg(colorflip(pos));
  v += threats_mg(pos) - threats_mg(colorflip(pos));
  v += passed_mg(pos) - passed_mg(colorflip(pos));
  v += space(pos) - space(colorflip(pos));
  v += king_mg(pos) - king_mg(colorflip(pos));
  return v;
}

```

Stockfish evaluates a position by linearly add each individual term. That includes piece values, square values, pawn structures, mobility, passed pawns etc. Nothing special here.

* How to get those values, known as **parameter tuning**? Nobody knows for sure, we have to adjust the parameters, play many games, look at the results. Sounds dumb? Yes, it is, but that's what all chess programmers do. Google's AlphaZero is no exception.
> 4 votes

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Tags: engines
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# Question
Title: Polyglot Opening Books vs. Chess Opening Tree
Depending on the GUI, I have noticed some use polyglot files for their opening books and others use .ctg(chess opening tree) for their opening books.

Is there an advantage or disadvantage to either or is it based solely on the programmer's preference with no real advantage or disadvantage?

# Answer
> 9 votes
**Let's take a look what they are**

* Polyglot is an open source format. It is free to use, free to distribute, the file format is in **public domain**. You won't land yourself into any potential legal disputes with Polyglot, as long as you follow the GPL license for the source code.
* CTG file format is owned by Chessbase. It's a closed format, and is not open for you to modify. The file format is **proprietary**. You might land yourself into possible legal disputes if you try to do something stupid. You --might-- need Chessbase's explicit permission if you want to embed it into your own application. Check with your lawyer.

People use Polyglot because:

* It's free. The source code is there for everyone.
* They don't know how to read the Chessbase opening file format
* Open source chess engines don't use CTG. They generally use Polyglot or nothing. I believe it's illegal to embed a proprietary software (you need code to parse the CTG file) into an open source program.

People use CTG because:

* It's a more powerful file format than Polyglot. The Polyglot format is really a binary compression of (position, moves, weights). For example, it **doesn't** have the number of games for each position.
* Polyglot is designed for computer chess engines, it sits nicely with engine code, but lacks good support for chess GUI. CTG format is designed for both chess engines and chess GUI.
* CTG is a more popular format than Polyglot. Most opening book makers use the Chessbase software.
* Polyglot was developed on the UNIX operating system, the source code is much harder to compile on Windows. But most chess book makers use Windows!
* There's an experimental CTG loader from scidb, and the related Java implementation somewhere else. However, the implementation in scidb is quite difficult to pull out (not abstracted in software engineering terminology). The Java implementation is useless if your application is not written in Java.

If both CTG and Polyglot were open source and free, there wouldn't be any reason for Polyglot to exist. CTG \> Polyglot.

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Tags: computer-chess
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title: Premove techniques

text:
# Question
Title: Premove techniques
When playing online, you have the option to *premove* (enter the next move, before it is your turn). I am wondering whether there are (generally useful, not contrived) situations where say you have 20 moves to mate with perfect play, but with little time you might be better off going for a longer mate in 30 moves which you can largely premove.

As an example: For the simple endgame rook+king vs bare king, I am aware of two techniques:

1. gradually decreasing the available space for the enemy king in both horizontal and vertical directions. This can be done without giving check and requires the king to protect the rook most of the time
2. gradually decreasing the available space for the enemy king in one direction only (horizontal or vertical) by giving check from the side when the kings are in opposition

I believe the first method is quicker, however the second might be easier to premove (not sure).

# Answer
Almost always the 30 move option is better. There are 2 key reasons: \- You only lose 0.1 seconds per premove (on most servers), compared to 0.5 - 1.0 seconds. \- Your opponent loses more time since you limit their thinking period by moving instantly.

In my opinion, this is the primary reason why a situation like K+R vs K largely favors the K+R player in bullet. The side with the K+R can *always* premove, since the lone King cannot create any threats/checks/etc. Meanwhile, the lone King often fails in premoving because the Rook controls squares/gives checks/etc.

If you're slightly lower on time in a sudden death game (say 15 seconds to 20 seconds), you could win just by premoving with the Rook, and trying to purposefully disturb the enemy King. If your opponent can only premove half the time, that's a whole 0.9 seconds they're losing *every move*. In 10 moves they have lost around 5 seconds (assuming only a 50% success rate in premoving), while you've lost 1 second.

However, if the time gap is more significant (5 seconds to 20 seconds, for example), premoving is not enough *on its own*. The trick is to premove while slowly trapping the enemy King. The strategy of how you box the King is irrelevant, since time in the key. As long as you premove every move and gradually push the King to one of the sides, it can be enough to win the game. By premoving each move, you're essentially turning 5 seconds into 50 moves.

However, only experienced bullet players (2300+) can premove *every* move while always making real progress. Thus, it wouldn't be uncommon to see a 2300 blow a win in a K+R vs K with only 5 seconds against 20 seconds.

The key is always premove and try to make some kind of progress; don't worry about the technique you use to box the King.
> 3 votes

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Tags: online-chess, online-blitz
---


title: Dealing with stress in competitive play

text:
# Question
Title: Dealing with stress in competitive play
Chess is one of many games I find highly stressful to play competitively. These games share one trait: I have plenty of time to think about what to do before making a move. On the one hand that's great since it makes the game independent of reflexes. On the other hand I have plenty of time to stew over how I might be making a massive blunder. This means I tend to be very nervous throughout a tournament. My heart rate can actually surge long before I sit down at the board, and stay high throughout the game. Comparatively, in games like tennis or *Street Fighter*, I can start a round nervous, but once I'm playing muscle memory takes over.

Chess is uniquely good and bad: if I lose, it's because I made a mistake somewhere; however that itself is a stressful thing - I can't blame bad luck.

What are good ways to deal with stress?

# Answer
> 7 votes
This article about Chess Psychology might help you reduce the stress you are feeling when playing chess.

> Psychology is an integral element of chess. To win a game (tournament, match) one needs to be strong not only in chess, but in the psychological sense as well. Every chess player can recall moments when he/she could not recover from a terrible loss (or draw) and kept losing points in other rounds. Or were surprised by a twist of the game and could not adjust to it. The chess elite pay a special attention to psychological preparation. For example, in 2008 the participants of the FIDE Grand Prix have been asked: “How do you handle chess failures?” I can relate to the views of Gashimov, Cheparinov, Bacrot, Jakovenko and Akopian.
>
> An improving chess player should not only study, practice, but also work on his psychology. Let’s consider two important aspects of chess psychology:
>
> 1. Your state of mind during the tournament (match) in general
> 2. Your state of mind during a certain game
>
> A regular tournament implies 1 or 2 games per day without any weekends or rest days. Therefore, if you have lost or failed to convert a totally won position and keep bugging yourself for it, there is a high chance you will end up in trouble again and waste a lot of nervous energy along the way. Your emotional discomfort may show in different ways. For example, if you are willing to strike back at all costs, you may easily forget about the objective evaluation of the position and start playing adventurously. Or you could get your mental batteries uncharged by worrying and lose due to lack of energy. Thus, it is very important to know how to deal with losses. Try to get over it as soon as possible. Do a quick blunder check, fix your opening, and forget about it until the end of the event. Take a good rest and concentrate on the next game. Remember that each loss is just a lesson. If you treat losses this way, it will be easier to handle defeats. After the tournament, however, you should analyze your games carefully and determine your chess weaknesses so that to know on what to work in the future. This is absolutely critical for one’s chess improvement.
>
> A chess game is a confrontation between two partners. The struggle is going on not only at the board, but between their identities. Mistakes are inevitable, and the one who manages to keep his cool has higher chances of winning.
>
> First of all, you should feel confident at the board. I mean real confidence, concentration, being sure you can play well, right posture, not some freaky “death stares” or “arm-wrestler’s handshakes”. If your opponent feels you are faking it, he will become more motivated to win.
>
> Secondly, never blame yourself for blunders (“ok, I’m a bit better now, but I would have won already had I played 25.Nf6…”) during the game. Otherwise you may become so obsessed with it you will make matters even worse. Take the game as it is, re-consider the evaluation of the position and try to play on calmly, as if nothing unexpected has happened.
>
> Thirdly, it’s a great idea to try to lure your opponent into the type of positions he likes least of all. He will both be irritated (and that increases the probability of making a mistake) and outplayed (since he generally doesn’t know how to handle such positions).
>
> Never resign too early and keep defending bitterly and tenaciously. A lot of totally lost positions have been saved even against world class players. When you are on the other side of this situation (i.e. winning), never relax until the game score sheet is signed in your favor. Otherwise you may see your lovely 1-0 turn into ½-½, or even into an ugly 0-1.
>
> These are the main rules of chess psychology, not to mention “the Dark Side” – how to suppress your opponent and make him lose comfort and confidence. Since I am neither practicing nor advocating the usage of such foul play, we won’t be discussing it in this article.

# Answer
> 7 votes
# Equanimity (detachment with results)

The other answers are good, but I feel that they miss one fundamental, critical aspect of Stress Management in any field or situation.

It can be captured in one word: **Equanimity**. Or, in other words, **detachment with results**. You should try to make yourself **as unconcerned as possible** with the result of your game / match / tournament.

This is by far the **most** effective way of dealing with stress in any situation, whether related to chess or otherwise. Furthermore, if this is not done, that is, if there is a lot of attachment with, and concern about the results, no amount of breathing or walking will reduce the stress with any degree of significance.

The following three verses from the Bhagvad Gita (a Hindu scripture) perfectly summarise the attitude that you need to have. They frequently help me in dealing with stress / anxiety / concern in my own life.

1. कर्मण्येवाधिकारस्ते मा फलेषु कदाचन | मा कर्मफलहेतुर्भूर्मा ते सङ्गोऽस्त्वकर्मणि || 2.47 ||

English Translation: **You have a right to perform your prescribed duties, but do not consider yourself entitled to the fruits of your actions.** Never consider yourself to be the cause of the results of your activities, nor be attached to inaction.

Swedish Translation: Din omsorg gälle gärningen allena, och ej din gärnings frukter; — låt ej dessa förleda dig att handla, eller fjättra din höga själ i dådlöshetens band!

2. दु:खेष्वनुद्विग्नमना: सुखेषु विगतस्पृह: | वीतरागभयक्रोध: स्थितधीर्मुनिरुच्यते || 2.56 ||

English Translation: One whose **mind remains undisturbed amidst misery, who does not crave for pleasure, and who is free from attachment, fear, and anger,** has a steady intellect.

Swedish Translation: i smärtans stund, och lockas ej av njutning; han bindes ej av lidelsernas bojor, av fruktan, hat och vrede, och han kallas en helig man och en ståndaktig själ.

3. य: सर्वत्रानभिस्नेहस्तत्तत्प्राप्य शुभाशुभम् | नाभिनन्दति न द्वेष्टि तस्य प्रज्ञा प्रतिष्ठिता || 2.57 ||

English Translation: One who **remains unattached under all conditions, and is neither delighted by good fortune nor dejected by misfortune**, he is a sage with perfect knowledge.

Swedish Translation: Vad hända må av ljuvligt eller lett, är dock hans ande fri på varje håll, och känner varken lystnad eller avsky; — han eger verklig jämnvikt i sin själ.

Swedish translations from: http://www.gutenberg.org/cache/epub/48854/pg48854-images.html

# Answer
> 5 votes
Dealing with stress in competition is one very important aspect of a well-rounded preparation strategy. I think that the most crucial point in answering your question is actually contained within the question itself:

> "These games share one trait: I have plenty of time to think about what to do before making a move. On the one hand that's great since it makes the game independent of reflexes. On the other hand I have plenty of time to stew over how I might be making a massive blunder."

I'll assume that either you are faster than Magnus Carlsen at thinking, or that you tend to play longer games. Since most of us do not think about chess faster than Carlsen, I'll go with the "longer game" option. This makes things quite a bit easier than if you were playing Blitz, Bullet, Lightning, or Armageddon games. There is enough time on the clock for you to do a self-assessment, get a grip on yourself and direct your thoughts appropriately - *if you know the tricks of how to do so.*

Here are a few things that I've found to be helpful.

1. **Breathe properly.**

Most of us, when stressed, will naturally hyperventilate (breathe too quickly). We then blow out a lot more of the CO2 in our blood than we normally would, out into the atmosphere. Our bodies actually use the concentration of CO2 in our blood to gauge how much oxygen we're getting, so it thinks that because we have a low CO2 level, it means our tissues don't need that much extra oxygen *even though we do*. What happens next? Our body sends even less oxygen to our brain than before, because our hyperventilating has tricked it into thinking we don't need it! We then stress out even more because our brain is now lacking even more oxygen. This cycle goes on and on, and our performance suffers more and more because of it.

How do we fix this problem? We need to find a way to allow our CO2 levels to come back up so that our body transports more oxygen to the brain.

Many people who need to perform at their peak have adopted a strategy developed by the military that goes by many names: For the sake of what we're doing today, we'll call it "Box-breathing." It is incredibly simple, and if we apply it when we're stressed, it can get our physiology back to doing what it should have been doing all along. I personally have found this technique to work even better if you focus on keeping good posture and relaxing your neck muscles.

The technique:

Use Box breathing before, during, and after your games. Give yourself reminders until doing so becomes a habit.

2. **Take care of your physical condition**

Chess is a sport, and participants of a sport need to take care of their bodies. Think about the heart muscle; if you're in average shape, it will pump nearly 4000 times in an hour to deliver oxygen and nutrients to your brain and body, and to take waste products and CO2 away. Your heart rate is intimately connected with other aspects of your physiology such as breathing rate and stress level. What would happen if your heart could pump the same amount of blood to your tissues during a chess game, but beat fewer times while doing it? Your stress level would go down to an even more manageable level.

How do you achieve this fitness? By exercising your heart muscle. The Mayo Clinic recommends that we all reduce our time spent seated, get a bare minimum of 30 minutes per day of physical activity, do strength training twice a week, and get at least 150 minutes of moderate aerobic training, or 75 minutes of vigorous aerobic training in a week. This guideline is a *minimum*.

Indeed, I recommend testing yourself once a month with some easily standardized test such as the 12-minute Cooper's Test: You run for 12 minutes, and write down how far you went. Then, set a goal for next month, and train accordingly. Focus on small, consistent improvements in physical fitness - it will certainly show in other aspects of your life, too.

Another recommendation is to cut out refined sugars, simple carbohydrates, and processed foods from your diet; replace them with things like green, leafy vegetables, and drink plenty of water. Not only will it help you in your fitness goals, but it will also keep your blood sugar consistent, and keep you from getting heart palpitations and high stress at the most inopportune times.

Stick to a manageable eating schedule, and see what works for you during periods of stress. Bring something appropriate with you to tournaments.

Finally, make sure to get enough sleep. It will make your chess practice more efficient due to the fact that you move information from short-term to long-term memory while you sleep. It will also help to clear your body of toxins. It works even better if you consume one cup of water before going to bed.

3. **Don't think about a blue elephant**

Gotcha! I'll bet you thought about a blue elephant even though I told you not to. Don't worry; we all do. Interestingly, the fear of failure works in a similar way. There is a healthy way to hate losing, and there is an unhealthy way. The healthy way is to let it be a motivating and directing factor to mold your practice in an appropriate way. The unhealthy way is to stew over making a massive blunder, thus interfering with your decision-making in game.

In game, I highly recommend going back to "Box breathing," and once you've gotten yourself in a better frame of mind, go back to your game plan. This, of course, means that you must make sure to have a plan going into every game, both for how you will take care of your psyche, and how you will play with the pieces and chessboard. This leads directly to point #4 which is:

4. **No matter what the tournament is, your primary goal should always be to improve.**

You've done your preparation, you're healthy, you're well-rested, you're breathing properly, and you're ready to go. *All you can fairly expect from yourself is to do your best.* There will be time to analyze your games after the tournament is over, and improve for the next one. No matter what good moves or blunders you may make through the course of the game, keep your focus on the present: Don't disregard your plan for flashy moves that are tempting, but after calculation show that they don't actually improve your position or further your plans in any way; don't lose your cool when your opponent plays an unexpected move.

Do your calculations, move your pieces, and play your best. On tournament day, keep your focus on playing good chess, and save your game analysis for whenever you get enough time to do so peacefully. If you start getting the urge to beat yourself up over a loss, or unduly congratulate yourself for a win, give yourself permission to do that in another time or place. Right now, you're in a tournament. Observe your opponents' strategies and consider how to defeat them. Play your own strategies and focus on your strengths. If you've properly done the previous three points, you will be in a good position to do so. Give yourself gentle reminders as necessary, or even better, recruit someone else to come with you, bring drinks, snacks, and be a support for you.

I hope this helps.

In summary:

1. Breathe properly
2. Take care of your physical condition
3. Don't think about a blue elephant
4. No matter what the tournament is, your primary goal should always be to improve

# Answer
> 2 votes
The stress you feel comes from the adrenaline that your body produces to help you fight or run away. So the best way to handle this physical reaction is by physical things.

First, before the game try and go for a brisk walk of at least 20 minutes. This will help to burn up some of the adrenaline.

Second, during the game don't stay stuck to your chair, try and get up from time to time, look at other games, go and get a glass of water, etc.

Third, do deep breathing exercise to help calm yourself. Breathe in slowly and completely for a count of between 4 and 8, hold the breath for a count of 4 to 8, breathe out slowly and completely again for a count of between 4 and 8.

Finally, try and be in good physical shape to begin with. Physical preparation was an important component of the old Soviet school of chess and is advocated and practiced by coaches and many top players today. Gary Kasparov even mentioned it on Sunday when he was on the BBC radio programme "Desert Island Discs".

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Tags: tournament
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title: How does one find the tactic here?

text:
# Question
Title: How does one find the tactic here?
```
1rr3k1/p3p1b1/b2p2pB/q2P1p2/4P3/1PNn1PK1/P1RQN1PP/7R b - - 0 23

```

In the above position (reached after 1. Bxh6?) Stockfish points out that Black has a winning move, going from 0.00 to -2.25.

However, I cannot find the tactic. Here are some details I have pointed out.

Checks: Black can check with Be5+ or f4+.

Captures: Black can capture the knight on c3 if a defender is removed: There are three attackers and three defenders on the square. The Black knight on d3 is protected by the bishop and is not hanging, so it cannot be captured. White can capture the g7 bishop, an attacker of c3, on the next move.

Threats: White cannot take the pawn with the knight after 1... f4+ because that removes a defender of c3. White cannot take with the king either because that interferes with the queen's defense of h6, and thus Bxh6 is possible (skewer). The intermezzo 2. Nxf4 does not work because of 2... Bxc3, attacking the queen.

**Please only provide hints and not the actual winning move.** What are the tactics (such as deflection, coercion, attraction, etc.) that Black should look for?

# Answer
I see you looking at "forcing" moves such as checks and captures. This is probably a good place to start. One of the best features about "forcing" moves (especially checks) is that the opponent is limited in their possible responses. Both checks you have available, for example, allow only six possible responses; that's way easier to calculate than the 36 or so moves he'd otherwise have. A capture allows for more *possible* responses than a check, but most of them are obviously bad if they don't regain the material, so that also limits the required calculations.

So, for each candidate move, go through each of their responses, one by one, and see if you have a good reply to it. You've started this with a couple of moves; finish it for those moves, and if they don't appear to be correct, move on to the other forcing moves. If you still cannot find it, look for other candidate moves (such as ones that create threats.)

(I'm not going to provide an actual hint because I see someone else already did, and you probably don't want two.)
> 2 votes

# Answer
You are almost there with your analysis. Tactical motives you should look out for are:

overloading, interference, distraction, skewer
> 2 votes

# Answer
I first noticed that the knight on e2 seems to be overloaded, defending both the knight on c3 and the f4 square.

f4 looks interesting, because there are 2 ways your bishop can control that square, potentially pinning a piece that lands on it to either white's king or queen.

I don't want to analyze more than that, you asked about how we would approach finding tactics. Look for overloaded pieces, pinning squares, discovered checks, etc.
> 2 votes

# Answer
Have you considered how the white bishop can lose contact with the White queen on d2?
> 0 votes

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Tags: tactics, kings-indian
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title: Tournament (After 10 year hiatus...)

text:
# Question
Title: Tournament (After 10 year hiatus...)
Good afternoon everyone,

\*This is my first post on this forum, so if I placed this in the wrong section, please let me know.

I used to play regularly back in high school and stopped once I started college. I found my passion again and finally started training/studying again in the past few months and noticed there was a tournament coming up not too far away from where I live.

It’s the 7th Annual Reno Larry Evans Memorial (https://sites.google.com/site/renochessclub/lem/tournament#EntryInstructions)

I personally feel my chess has improved (definitely personal opinion), but I haven’t had the opportunity to play OTB in a while, so the majority of my games have been online.

My USCF rating back in early 2008 was the following (this was based on 46 games):

* Regular: 1,376
* Quick: 1,352
* Blitz: Unrated

My Lichess rating from the past few days have been:

* Classical: 1,748
* Rapid: 1,722
* Blitz: Unrated

**I completely understand that online ratings are definitely inflated**, so I’m assuming my rating is much lower than the 1,700s. I was considering entering into the tournament and it looks like I would fall under the “D” Section. And this leads to my questions:

1. I regularly play 30+0 games and am definitely more comfortable with longer times compared to shorter blitz games. This tournament is 40 moves/2 hours, SD/1 hour, 5 second delay. From your experience is this a drastic change?
2. If I apply for the tournament now, would I be in the “D” Section even if I haven’t played in a tournament in over a decade?
3. If I apply under the “D” Section now, join a chess club and in the 2 months prior to the competition get a rating over 1,400 would I automatically be placed in the “C” Section?
4. I’m assuming I need to be a USCF member before I apply, correct? If so, how long is the process?
5. Do you think if I prepare for the tournament for the next two months (reviewing end-game/middle-game, tactics, and at least one game per day), I will do well? $150 entry fee is on the larger end for me, so want to be sure I justify it for the wife.

I know this was quite a lengthy first post, but its has been a while and want to understand the topic before committing. I appreciate any feedback or suggestions. Thank you!

# Answer
Regarding your questions:

2+1 hours is a big difference to 30-0, which is basically rapid chess. With 30-0 you'd rarely think at a move more than a minute or so. At your level this should be enough to avoid obvious blunders, but the longer time control allows you to invest say 10-30 minutes or so at a complicated position in order to really delve into the position and to calculate longer forced lines or develop long term plans. Might be worth playing some games at the longer time control prior to the tournament.

I'd ask questions 2 or 3 to the organizer unless it is specifically stated in the tournament regulations.

USCF membership seems to be required. It says, *New memberships/renewals available at site.* so that should not be a problem.

Too many unknowns to say how you will perform.
> 3 votes

# Answer
> I regularly play 30+0 games and am definitely more comfortable with longer times compared to shorter blitz games. This tournament is 40 moves/2 hours, SD/1 hour, 5 second delay. From your experience is this a drastic change?

40/2 SD/1 d5 is a rather drastic change from even G/60, let alone G/30. And it's not just the fact that you have more thinking time in a particular game that matters. Two games that each last 6 hours means twelve hours of chess in one day. Given that some rounds start at 7pm, that means you could be playing until 1 am. Fatigue can be a factor.

> If I apply for the tournament now, would I be in the “D” Section even if I haven’t played in a tournament in over a decade?

Yes, unless you choose to play up. USCF ratings don't expire even if the membership does.

> If I apply under the “D” Section now, join a chess club and in the 2 months prior to the competition get a rating over 1,400 would I automatically be placed in the “C” Section?

It depends on when exactly your rating goes up. According to the USCF, "Official ratings lists are generated on the 3rd Wednesday of each month and become official on the 1st day of the next month." The tournament starts on March 31, and the third Wednesday in February is February 21, so I think any ratings change wouldn't affect your section unless it occurred before February 21.

> I’m assuming I need to be a USCF member before I apply, correct? If so, how long is the process?

You need to be a USCF member to play; I'm not 100% sure whether you need the membership to register for the tournament, but it seems likely. The process shouldn't be too long. The online form for USCF membership is currently here, and it's mostly just basic information (the one thing you might not remember is your old ID number, but there's a link to the search page from that form, so you can look it up if needed.)

> Do you think if I prepare for the tournament for the next two months (reviewing end-game/middle-game, tactics, and at least one game per day), I will do well?

That's impossible to say for sure. It depends on your expectations, among other things. In a six-round tournament, just one game can be the difference between a slightly good result and a slightly bad result, or a slightly good result and an awesome result. But you do have recent games (it's not like the tournament is the first time in 10 years you'll be playing chess), and you do have previous over-the-board experience (even if it's old.) You'll generally know what to expect, and that helps. I'd be cautiously optimistic.
> 3 votes

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Tags: rating, tournament
---


title: Algorithm for implementing chess rule

text:
# Question
Title: Algorithm for implementing chess rule
It's my first question on the chess stack exchange (actually I asked this question to stack overflow but my question was closed 'off topic'), and English is not my first language. So please understand if my explanation is not clear.

I'm a programming novice. I can use some of C (actually I forgot even basics of C), python, IDL just for scientific calculations, or for graphing.

I'm a moderate custom map maker for Starcraft 1. Yes, old fashioned game. Till lately only algorithm I need to make an custom map in Starcraft was trigger, which consists of condition(if~) and action(do~). There was no more complex algorithm like loop or like that.

However, recently there were much advance in the technology of making custom map with the popularization of EUD trigger.

EUD stands for Extended Unit death Trigger. There is an action in Starcraft trigger named 'Set Death'. The point is, you can set the death value of certain unit (of certain player) outside the allowed range. That makes possible to access and change other game data, like unit attack range or unit appearance(though extreme exploitation were limited in Starcraft:Remastered)

And one map maker (and programmer) made a programming language named epScript in which you can program a custom map and that would compile your script into Starcraft triggers and automatically embed them in a map.

And he wrote some lectures about how to use the language and compiler and the example he chose was the Chess. https://github.com/phu54321/euddraft/wiki

So you can play Chess in Starcraft Battlenet. (Well it was possible before when EUD was enabled but it was a result of such a lot of labor.)

However unfortunately he has stopped midway and I have some reasons to believe that for a while he'd not complete his lectures. So I'd like to continue and complete the chess map for two person, and besides, I wanna apply the principle to make a variant of chess, Kriegspiel, which is one of my favorite board game. https://en.wikipedia.org/wiki/Kriegspiel\_(chess)

Anyway, before that, I want to make chess (PvP). But as I said, I'm novice in programming, so I'm not accustomed to make algorithms to realize chess mechanism. So like, I'm not sure how to make script for disabling king to go into a checked cell.

Are there some webpages that lists algorithms for chess making , not language-dependent? I don't want AI algorithm for chess.(well after I finish the job, if I have enough time I may invest some time for that to enable PvC. And maybe for Kriegspiel too..?) I just want algorithms to implement chess rules. Thanks.

# Answer
> 2 votes
You're asking code for validating a chess position. There're a **lot**, tons and tons libraries. However, I don't think there's anything that you can compile for StarCraft. Consider:

1. Learn chess yourself. Make sure you know the rules well.
2. There's **nothing** you can just grab for your project. You'll need to do it yourself. If speed is not important, you could encode the chess board as a 8x8 two-dimensional arrays. Simple programming. Loop throught the arrays for moves, slow but it'll work for sure.
3. If speed is important, consider bitboard implementation. Please google bitboard for chess.

Some references:

and many many more. Decide your programming language. Your question is too broad for us to answer.

---
Tags: rules, computer-chess
---


# Question
Title: Is it ethical to spar against an engine when playing correspondence?
I started playing correspondence on chess.com purely for the fun of it and to gain some deep learning (i.e. there's no prize involved).

We are about 10 moves in and coming close to me being out of book. To help my learning, I'd like to set the position up against a computer and spar against that. I am not interested in the computer's evaluation, recommended moves for me etc. I'm really just interested in practicing from a specific position.

My question is, **is it ethical to spar against a computer between moves in a correspondence game?**

# Answer
Chess.com's site rules have the following to say:

> You can NEVER use chess programs (Chessmaster, Fritz, etc) to analyze current ongoing games unless specifically permitted (such as a computer tournament, etc). The only type of computer assistance allowed is games databases for opening lines in Turn-based Chess and Vote Chess. \[...\]

So it boils down to the question if playing out positions from a corr game against an engine counts as analyzing.

The answer can only be "yes" because for some possible continuations of your game, the engine provides its best moves. This is clearly an act of analysis.

There will be plenty of time to play against your engine after the game jas finished.
> 32 votes

# Answer
In chess we have to find the best move to play. In order to achieve this, we calculate several moves ahead. By using a computer 'only for sparring' you're effectively limiting the depth of your search tree by half - namely the opponent's moves. This is not like starting the 100m sprint at the 50m line and asking if it's ethical, because the number of possible lines grows exponentially with the depth of the tree. It turns out using a computer for only your opponent's moves is more like starting the race 87m ahead.

On Chess.com specifically computers are never allowed (as the rules state), although correspondence chess usually allows computer analysis for all moves. See the lack of a rule against it in the International Correspondence Chess Federation (ICCF) Rules.
> 7 votes

# Answer
The answer is simple, and nobody has come out and said it: NO. Not ethical. You need to either disclose to your opponent, find a way to save the game, and play with the computer later. The reason it is not "ethical" is because the other player assumes they are playing a human only, that is the underlying assumption. I don't think it is "terribly" unethical, but it kind of fits the very definition of unethical, it is violating the understanding between you and the other player. Full disclosure will handle it, and the other player can decide to play or not. My chess computer is so damn good, I can beat anyone, if I secretly use it! Wish life itself were that easy.
> 3 votes

# Answer
If you want to do this, you *must* play on a site whose rules explicitly permit it. FICGS(www.ficgs.com) expects that its players, who call themselves 'centaurs', will use computer assistance to the maximum. I tried it for a while. Anyone who is not a geek will find it very tiring.
> 3 votes

# Answer
As mentioned, it's against the rules. But if you just want to learn and have fun, just play against a computer in the first place. Why even involve another human being? You'll get the same practice benefits you want without any ethical concerns.
> 2 votes

# Answer
As others stated I think it depends on the server's rules. If the server allows it then of course it isn't unethical. If the server specifically states that you can't then its unethical. You agree to their terms by playing on their server.

As you are sparring against the engine you will be influenced on how to make the next move in your current game. Doesn't mean you had intentions of cheating just means, you analyzed the position and if you play to win, regardless if a prize is involved or not, you will naturally go against the move that isn't good to play because you sparred against, essentially, a super grand master and you want to win. That isn't fair play to your opponent on a server that has rules against using a computer.

My suggestion would be, if you are on a server that has rules in place against using computers during play, make notes in your game where you want to analyze and analyze the game AFTER the match is over.
> 2 votes

# Answer
USCF correspondence chess rules forbid the use of computers except to record moves. In other words, you can not use the engine for any form of analysis.
> 0 votes

---
Tags: online-chess, etiquette, correspondence-chess
---


# Question
Title: What is the best reply to Qe5+/Qe6+ in Scandinavian?
```
[FEN ""]
1.e4 d5 2.exd5 Qxd5 3.Nc3 Qe5+ ( 3... Qe6+ )

```

What is the best reply to this ? I know that it isn't very good move for black, but I met it few times. I thought that Be2 is the best because other moves block bishop and it is bad later in the game. Am I right ?

# Answer
Yes, Be2 is the best move to play against both Qe6+ and Qe5+. There are a few reasons for this:

1) Be2 does not block any of your Kingside pieces from developing, allowing you to castle quickly and then attack Black's misplaced Queen. While Be2 does block one of your pieces (your White Queen on d1), this is fine because you shouldn't be developing the Queen early anyways.

2) Be2 does not allow Black to exchange their misplaced Queen off. This allows you to use the Black Queen as a tempo-gainer (i.e., later in the game you can develop your pieces with tempo by attacking it). If you played Qe2 instead of Be2, it would give Black an opportunity to get rid of their bad Black Queen.
> 2 votes

# Answer
Keeping the queen in the center vulnerable to attack cannot be Black's best option. Be2 is the obvious move for reasons you gave. Black can't exploit it, and while e2 is not the best of squares for the bishop, it's still development.

David Letterman played the 3...Qe6+ line against Kasparov in a televised game. Kasparov played 4. Be2, and after 4...Nc6 5. d4 Qg6 5. Nf3 Qxg2 6. Rg1 Qh3 he had a massive lead in development. This is the line I'd go for against Qe6.

3...Qe5+ is just as bad since a future Nf3 will gain another tempo. 3...Qe5+ 4. Be2 c6 (or where is black going to put the queen after Nf3?) 5. Nf3 Qc7 and white again has a massive lead in development.
> 3 votes

---
Tags: opening, scandinavian-defense
---


title: pgn-extract program troubleshoot

text:
# Question
Title: pgn-extract program troubleshoot
Anyone familiar with the program pgn-extract to possibly help with a little troubleshooting? I have tried to look through manual of the program and I am coming at a loss with addressing the issue. I have tried using pgn-extract program commands -C, -N, -V with no affect. Here's the following line from my .bat file.

https://www.cs.kent.ac.uk/people/staff/djb/pgn-extract/help.html for manual reference.

Objective-I am trying to clean up a .pgn file that was created by combining multiple .pgn files together via either dos commands.

> copy \*.pgn newfile.pgn

or

> copy /b \*.pgn newfile.pgn

Issue-.pgn code errors. In both attempts at combining multiple .pgn files I get similar errors. See screenshots.

improper header spacing examples(text editor used is Brackets). This is causing a variance in multiple GUI's calculation of total games in the database. Preferred fix would be to use pgn-extractor to clean the pgn file by properly placing the header of the next game in the proper position below the previous game so the GUI can correctly count total games. I know how to manually fix this but I'm also building a separate opening book that will have a thousands of games in and in case this issue happens with that, would like to find a fix beforehand.

# Answer
> 4 votes
I am the author of pgn-extract. It would be easier to address the specifics of what you are trying to do via the personal email address included with the pgn-extract documentation. I would be happy to help.

David

# Answer
> 1 votes
I don’t know if pgn-extract can do that, but you might want to try sed. Use sed to do a global replacement for \[Event, insert a new line to the beginning of the string.

---
Tags: software, pgn
---


# Question
Title: Chess apps that provide a 3D view of the board and allow export of PGN
I'm looking for an Android chess app that satisfies the following criteria:

* Provides a 3D view of the board and the pieces (required)
* Allows one to have an account, and invite friends to play matches online (required)
* Allows export of PGN (optional)

Could someone suggest such an app?

# Answer
> 1 votes
Chess.com is probably one of the world's most popular online chess platforms. It has an app and a website (which offers many more features, such as a beta 3D view). In both, you can export game PGNs and have an efficient friends system in which you can challenge people to play. There are also many other beneficial features- free lessons from master players, tactics training, vision training and numerous drills to improve endgame play, as well as Stockfish analysis. Hope this answers your question.

---
Tags: online-chess
---


# Question
Title: What are some good plans for Black in this position?
```
rnbqk2r/ppp1ppb1/3p1npp/8/2PPP3/2N5/PP1B1PPP/R2QKBNR b KQkq - 1 6

```

Normally, White plays (after 0... h6) 1. Be3 Ng4 2. Bc1, when Black has gained tempi but weakened his kingside.

Suppose White plays 1. Bd2 instead. Instantly I see that I can play 1... Nc6, and I don't want to play 1... c5 because the bishop on d2 aids the defense of White's queenside.

My biggest concern with 1... Nc6 is 2. d5 Nd4 3. Bxh6 Bxh6 4. Qxd4. Do I have enough compensation for the bishop pair?

And are there better moves than 1... Nc6 or 1... c5? Maybe I can play 1... c5, 2... e5, gaining central space and eventually gaining an outpost should White play f2-f4.

# Answer
I would castle and Kh7. This does allow for white pawn storm more effectively, but I feel that black's counterplay comes quickly.

The pawn sacrifice is interesting, although I prefer to play 3...Rxh6. Black would have total control of the dark squares and white has a bad bishop. Either side white castles on would give black attacking chances due to the open line for either the rook or the DSB.

Black's most active piece is the DSB, therefore c5 is a good move in most cases. If white castles on the kingside, the standard attacking plans involve the f5-f4 push.
> 1 votes

---
Tags: opening, kings-indian, hypermodernism
---


title: Is my rating good?

text:
# Question
Title: Is my rating good?
I used to play chess a lot when I was younger (started when I was 2), but then a few years ago I stopped at around 10. I recently picked it up again and wanted to see how good I still am, so I took an online test. It says I'm rated 1746. I turn 16 in about a month. Is my rating good for my age?

# Answer
When people ask if they are "good", the question becomes, good compared to what?

Assuming your USCF rating would really be 1746 (which is hard to say from an online test), that would not put you in the top 100 US players age 15. You would need a rating of 1931 to make that list, currently. But it would get you the 26th spot on the top US girls age 15 list. It would put you in the top 4% of junior players, about the top 35% of adults, and about top 10% overall. It beats my current rating by two points. If you had played in my high school league, you probably would have won almost every game.

Of course, the best way to find out how good you are isn't to take a test - it's to play games! It's one thing to be able to spot a mate in 3 when you're told there's something special about the position; it's quite another to see it when you're playing a game or to cause such a position to happen in the game in the first place.
> 6 votes

# Answer
That depends on the test you took, and on the person you ask. A Grand Master will teill you that 1746 is bad, a beginner will tell you that it is good. Best way to evaluate your chess skills is to play games and tournaments against humans.
> 1 votes

---
Tags: rating
---


title: Continuation in the sicilian

text:
# Question
Title: Continuation in the sicilian
I played a game today in the Sicilian Defence. I was White. I was surprised to see the move 5. ... e5 ! Is this playable in the Sicilian?

```
[FEN ""]
[StartPly "5"]
[Title "Is 5. ... e5 playable?"]

1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e5

```

My intuition tells me that this move weakens the d6 square so much and White can develop an attact quite easily. The continuation

```
 [FEN ""]
[StartPly "5"]
[Title "Is 5. ... e5 playable?"]

1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e5 6. Ndb5

```

is obvious. White seizes control of the b5 square aiming for the weak d6 square.

I believe that Black should answer 5. ... e6 taking away the important d5 square from White. Has anyone seen the ... e5 variation before?

# Answer
> 5 votes
This is the Sveshnikov Variation of the Sicilian. It is a fairly popular line even at the highest level.

You are right, that 6. Ndb5 is the critical move. The game usually continues from there: 6. ... d6 7. Bg5 a6 8. Na3 b5

Black has somewhat weakened d5 and the pawn on d6 is weak, but in exchange he has expanded on the queenside and is threatening a fork on b4.

# Answer
> 1 votes
This is a well-known variation of the Sicilian - the Sveshnikov (B33). Black weakens squares on the d-file, but he gets queenside tempi in return. The main line continues 6... d6 7. Bg5 a6 8. Na3 b5 9. Bxf6 gxf6 10. Nd5 f5, where many games have been played and have gone both ways.

---
Tags: sicilian-defense
---


title: The end of anti-computer chess

text:
# Question
Title: The end of anti-computer chess
In the old days it was possible to beat computers basically by playing slow, closed positions with weaknesses that can be exploited in the long term, beyond the calculation depth of the engine.

As far as algorithms are concerned, what has been done to improve on this weakness of computers? Or is it just the increased calculating power/depth that makes beating computers so much harder nowadays?

# Answer
> 2 votes
Advances in the tactical acuity of the computer programs coupled with hardware improvements to CPU, memory, and disk storage, plus the availability of robust opening book and endgame tables has made them all but unbeatable.

I don't know if computers have strategic "thinking", but their tactical prowess is such that it doesn't really matter.

# Answer
> 2 votes
The development of Monte-Carlo tree-search has been a key element to overcome "horizon-effect" issues for chess softwares in the mid-2000.

# Answer
> 0 votes
Engines like Stockfish (Alphazero may be a different matter) are still not good at finding the best positional moves.

After doing an extensive study of the Fischer game collection, with the help of Stockfish, I just published a book on the theme:

While going through the positional test suite, including 112 test positions, I had to ascertain that Stockfish still fails to solve around one third, but maybe even close to half of the puzzles. With the tactical set, Stockfish has no problems at all, all solved.

Make the conclusions yourselves how weak actually Stockfish is and how strong Fischer.

So, you might just want to forget anything about alleged engine superiority in chess.

*Edit*: Here comes the FEN:

```
 [title "Exercice position"]
 [fen "r4rk1/2q1bpp1/pn3n1p/1pp1pP2/6P1/1BP4P/PP1N1P2/R1BQR1K1 w - - 0 17"]

```

# Answer
> 0 votes
I have explained my strategy in detail in the book.

1. Close the position,
2. Avoid immediate tactics,
3. Use concepts engines don't understand, like compactness of the pawn structure, unsheltered king with closed center,

a very wide range of other sophisticated concepts

```
[Event "Blitz 2m+2s"]
[Site "Microsoft"]
[Date "2018.02.06"]
[Round "?"]
[White "Lyudmil Tsvetkov, owner"]
[Black "Stockfish 9 64 POPCNT"]
[Result "1-0"]
[Annotator "owner"]
[SetUp "1"]
[FEN "rnbqkbnr/pp1p1ppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

 1. e4 {0} Nf6 {2.40/22 12} 2. Nc3 {3} Nc6 {1.75/21 7} 3. Nf3
{2} d5 {1.97/20 3} 4. exd5 {2} Nxd5 {2.15/22 5} 5. Nxd5 {1} Qxd5 {2.09/22 3} 6.
d4 {2} Bf5 {1.92/23 3} 7. c3 {2} Be7 {2.01/20 4} 8. Bd3 {2} O-O {2.02/21 3} 9.
Bxf5 {3} Qxf5 {2.17/19 2} 10. O-O {2} Rfe8 {2.09/22 3} 11. Be3 {2} Bf6 {2.23/
23 22} 12. Qb1 {2} Qd5 {2.07/22 0} 13. Qd3 {3} Rad8 {2.19/20 4} 14. Rfe1 {6} g6
{2.32/21 7} 15. Bd2 {5} Ne5 {2.30/19 3} 16. Nxe5 {3} Bxe5 {2.25/22 2} 17. b3 {
16} b5 {2.18/21 6} 18. Qf1 {0} h5 {2.42/22 19} 19. Rad1 {0} Bf6 {2.70/24 11}
20. Rxe8+ {2} Rxe8 {2.89/23 2} 21. Be3 {0} Rc8 {2.86/24 5} 22. Qd3 {6} Qf5 {3.
01/25 0} 23. Qxf5 {0} gxf5 {3.17/23 3} 24. Rc1 {5} Kf8 {3.24/25 9} 25. c4 {14}
bxc4 {2.46/22 1} 26. Rxc4 {4} Rxc4 {2.79/25 0} 27. bxc4 {1} f4 {3.07/24 4} 28.
Bxf4 {2} Bxd4 {3.31/24 4} 29. Be3 {2} Bb2 {4.06/29 9} 30. Bxa7 {3} Ke7 {5.02/
30 12} 31. Kf1 {9} Kd7 {4.44/28 4} 32. Ke2 {1} Be5 {5.18/28 7} 33. h3 {3} Bd6 {
4.98/23 2} 34. g4 {7} hxg4 {6.03/26 6} 35. hxg4 {1} Ke6 {6.35/26 2} 36. Kd3 {2}
f6 {7.18/25 3} 37. Be3 {8} f5 {7.21/21 0} 38. gxf5+ {4} Kxf5 {10.49/27 0} 39.
c5 {3} 1-0

```

---

```
[Event "Blitz 2m+2s"]
[Site "Microsoft"]
[Date "2018.02.05"]
[Round "?"]
[White "Stockfish 9 64 POPCNT"]
[Black "Lyudmil Tsvetkov, owner"]
[Result "1/2-1/2"]
[ECO "D94"]
[Annotator "owner"]
[PlyCount "111"]
[EventDate "2018.??.??"]
[TimeControl "120+2"]
[fen ""]

1. d4 {0.55/22 17} d5 {2} 2. c4 {0.51/22 8} c6 {3} 3. Nf3 {
0.54/23 8} Nf6 {2} 4. e3 {0.31/24 16} g6 {2} 5. Nc3 {0.59/21 3} Bg7 {2} 6. Be2
{0.45/23 6} O-O {2} 7. O-O {0.35/21 3} Bg4 {3} 8. a4 {0.53/21 5} a5 {0} 9. b3 {
0.47/22 7} e6 {11} 10. Ba3 {0.44/28 0} Re8 {2} 11. h3 {0.39/25 4} Bxf3 {3} 12.
Bxf3 {0.33/24 1} Bf8 {5} 13. Bb2 {0.42/22 2} Na6 {0} 14. Qc2 {0.34/21 3} Nb4 {3
} 15. Qb1 {0.35/22 13} Nd7 {23} 16. Na2 {0.24/28 0} f5 {11} 17. Nxb4 {0.31/24
11} Bxb4 {1} 18. g3 {0.66/19 2} Nf6 {3} 19. Kg2 {0.38/25 23} Ne4 {14} 20. Qd3 {
0.17/26 0} Qg5 {10} 21. Rh1 {0.48/22 10} h5 {2} 22. h4 {0.67/17 1} Qh6 {10} 23.
Rhc1 {0.57/22 3} Rf8 {0} 24. Qc2 {0.57/26 5} Rf7 {3} 25. Rh1 {0.49/25 13} Raf8
{2} 26. Be2 {0.40/20 3} Kh7 {0} 27. Bd3 {0.39/22 2} Qg7 {9} 28. Qd1 {0.39/25 3}
Qh6 {2} 29. Bc1 {0.39/26 6} Qg7 {2} 30. Qc2 {0.39/25 0} Rd7 {4} 31. Bb2 {0.39/
27 2} Rfd8 {4} 32. Rhc1 {0.39/23 3} Nf6 {4} 33. Be2 {0.39/20 4} Rg8 {9} 34. Bf3
{0.39/20 2} Qh6 {5} 35. Qe2 {0.39/20 2} Rdg7 {8} 36. Rf1 {0.39/22 2} Rd7 {9}
37. Rac1 {0.39/23 3} Kh8 {4} 38. Rh1 {0.39/23 2} Kh7 {4} 39. Bc3 {0.55/19 1}
Bxc3 {0} 40. Rxc3 {0.41/24 1} Ne4 {5} 41. Rd3 {0.41/21 2} Ra8 {6} 42. Rb1 {0.
41/22 1} Ra6 {3} 43. Qb2 {0.40/23 3} Rb6 {3} 44. Qc2 {0.36/21 3} Rb4 {5} 45.
Rf1 {0.12/23 2} Kg8 {9} 46. Rdd1 {0.12/21 1} Rf7 {0} 47. Be2 {0.12/25 2} Qf8 {
17} 48. Bd3 {0.11/35 0} Qd6 {3} 49. Ra1 {0.11/25 2} Rg7 {7} 50. Rab1 {0.11/24 2
} Kh8 {0} 51. Rfe1 {0.11/26 3} Qb8 {12} 52. Qb2 {0.11/21 2} Rf7 {2} 53. Rg1 {
0.11/27 2} Kh7 {3} 54. Qc2 {0.11/27 2} Qd6 {2} 55. Rgc1 {0.11/27 2} Rf8 {5} 56.
Qd1 {0.11/27 4} 1/2-1/2

```

Above the pgns for my first handicap win and my first draw with SF 9. Anticomputer chess still works, but you need more time to beat the very top without handicap.

Maybe someone is interested in such games.

---
Tags: engines, tactics
---


# Question
Title: Where to download a 6 man Nalimov endgame tablebase?
Can anyone tell me whereabouts I can download a 6 man Nalimov endgame tablebase? I've seen some websites with 6 man Nalimov (case in point: http://contentdb.emule-project.net/view.php?pid=1630). However, so far all I have come across is dead links.

Can someone able to point me to some working link(s)?

# Answer
> 4 votes
From the ICCF site: Players who wish to have access to the 7 men tablebases may purchase any of the following programs: ChessOK Aquarium 2017, Houdini Aquarium 2017, Houdini PRO Aquarium 2017, Chess Assistant 17 with Houdini 5 and Chess Assistant 17 PRO with Houdini 5 PRO.

Free Android application One more way to access 7-man tablebases without having a key is to use Android application.

Search for Lomonosov Tablebases or use https://play.google.com/store/apps/details?id=com.convekta.android.lomonosovtb

Alternatively, if players only want access to 6 men tablebases they may visit this page to use the 6-piece Nalimov tablebases: http://chessok.com/?page\_id=361

# Answer
> 0 votes
http://kirill-kryukov.com/chess/tablebases-online/

Just to show where I got the links from. Site came from Arena's Chess GUI's homepage. Site states they had permission from Eugene Nalimov & Andrew Kadatch.

http://www.playwitharena.com/?User\_Files%2C\_Engines:Axon%2C\_EloStat%2C\_Nalimov:Nalimov\_Tablebases

Found the link initially. Very informative for computer chess in general.
https://chessprogramming.wikispaces.com/Nalimov+Tablebases

---
Tags: endgame, tablebases
---


# Question
Title: Why doing the Engine suggested move worsen my position?
It is going from #26 through +60 to +9. Thats all engines best moves with deep analysis. Schould it not be a forced checkmate if I will follow the engine evaluation?

# Answer
> 2 votes
Stockfish (at a search depth of 99 moves) evaluates the initial position as actually a mate-in-19.

```
[FEN "2n5/1p6/1P3k2/R1K1p1p1/2p1PpPp/5P1P/8/8 w - - 4 1"]

1.Ra8 Ne7 Kxc4 Nc6 Kc5 Ke7 Rc8 Nd8 Kd5 Ne6 Kxe5 Kd7 Kd5 Ke7 Re8+ Kxe8 Kxe6 Kf8 e5 Kg7 Kd6 Kg8 e6 Kf8 Kd7 Kg8 e7 Kf7 e8=Q+ Kf6 Kd6 Kg7 Ke7 Kh6 Kf8 Kh7 Qh5#

```

The next position is a mate in 18 moves.

```
[FEN "R7/1p2n3/1P3k2/2K1p1p1/2p1PpPp/5P1P/8/8 w - - 6 2"]

1.Kxc4 Nc6 Kc5 Ke7 Rc8 Nd8 Kd5 Ne6 Kxe5 Kd7 Kd5 Ke7 Re8+ Kxe8 Kxe6 Kf8 e5 Kg7 Kd6 Kg8 e6 Kf8 Kd7 Kg8 e7 Kf7 e8=Q+ Kf6 Kd6 Kg7 Ke7 Kh6 Kf8 Kh7 Qh5#

```

The final position is mate in 17 moves.

```
[FEN "R7/1p6/1Pn2k2/4p1p1/2K1PpPp/5P1P/8/8 w - - 1 3"]

1.Kc5 Ke7 Rc8 Nd8 Kd5 Ne6 Kxe5 Kd7 Kd5 Ke7 Re8+ Kxe8 Kxe6 Kf8 e5 Kg7 Kd6 Kg8 e6 Kf8 Kd7 Kg8 e7 Kf7 e8=Q+ Kf6 Kd6 Kg7 Ke7 Kh6 Kf8 Kh7 Qh5#

```

You probably didn't give the engine sufficient time to find the mate.

Another important fact to note is that the Lichess app uses the javascript version of Stockfish. The problem with this version is that it cannot make use of hash tables. So when the engine evaluates a position and then left to evaluate another position resulting from a move in the initial position, it evaluates the position as if it was restarted before evaluation. I am pretty sure if you give the engine some time to evaluate the second and last positions it will come up with the mate.

# Answer
> 1 votes
Engines do not calculate *every single variation* up until their depth. It would take far too long to do this at a depth of, say, 20 moves. After only the first four moves in chess, there over a billion positions.

Engines choose what variations to calculate based off their evaluation algorithms (how they evaluate positions). For example, assume it gets to a position in its calculations where the opponent has 5 possible moves. If it evaluates that 3 of these moves are +10 for the computer, it could entirely skip these variations and only calculate the remaining 2. This saves large amounts of time and processing power.

Thus, if an engine calls "mate in X", that is really just its best guess. It's possible the engine incorrectly thought some variation was bad for the opponent, and thus chose not to calculate it. However, maybe it turns out this variation actually prolonged the game a few more moves.

An engine's evaluation algorithm is based on a number of factors regarding *the current position in its calculations*. Black could have had a move that "looked" worse to the engine (based off its evaluation algorithm), causing it not to calculate the resulting variation. Concretely though, this move could have been *objectively* the best, as it prolonged mate.

The reason an engine often changes its evaluation from "mate in X" to something like +60 is that, after "going down the rabbit hole" as far as it can, it then checks over and refines its previous calculations. It wouldn't make sense to refine/perfect its calculations first, as this is like the cherry on the cake. Analyzing to a high depth is of highest priority - refining its previous calculations is almost always secondary.

# Answer
> 0 votes
Many engines are notoriously bad at "remembering" their own variations from 3 moves ago and try to reinvent the wheel each move, so to say.

For me, the Lichess Stockfish calculates

* Mate in 22 for 1. Ra8
* Mate in 21 for 2. Kxc4
* Mate in 14 for 3. Rc8 (Black screwed up in his last move it seems)
* Mate in 18 for 3. Kc5
* Mate in 19 for 3. Rg8
* +64 for 3. Kd5

With search depth of 35 each time.

Looks like your analysis at move 3 did not go deep enough and recommended the "wrong" move Kd5 (which still wins, of course). Note that until a depth of around 30, I only got +50 to +60 evaluations too. My bet is that on your phone Stockfish could not reach the depth where it flips back to showing the mate. After making the move, it started to realize that it lost the track to the mate and began readjusting the evaluation (to +10).

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Tags: engines
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title: Capturing the king in a blitz game

text:
# Question
Title: Capturing the king in a blitz game
In a blitz game, when my king is checked, I make an illegal move that checkmated the opponent and pressed the clock. Then my opponent captured my king and claimed victory. Capturing the king is not a legal move. Who wins?

# Answer
This is a good question indeed and a somewhat bizarre situation, which is not fully covered by the Laws. As you mention the opponent has completed an illegal move and you claim that. The relevant parts of the Laws are articles `A.4.2.`, `B.2` and `7.5.5`.

The easy case is if your opponent has made an illegal move (that has been claimed) before. In that case they lose the game.

If this is a first illegal move your opponent has made in this game, however, then the arbiter will give you one minute extra time, the opponent's last move is taken back and they have to play any other move that is legal. This is where things become complicated. Your opponent has been checkmated and thus there is no legal move they can play. According to article `5.1.1` they should lose the game but only if the move producing the checkmate was legal, which it was not. Therefore, since your opponent cannot make any legal move, the game cannot continue but it has not finished and there is no result. Quite bizarre indeed.

The following is a somewhat bizarre solution to a bizarre situation. If the opponent is satisfied with a draw they could ask the arbiter to watch the next move and then make a move that leaves both kings in check. Then the arbiter will declare the game drawn according to article `A.4.4.`.

If the opponent does not want a draw then the only solution that satisfies the Laws is that both players agree to correct the illegal move that caused the checkmate. This is allowed by article `A.4.2`. If they don't agree the Laws do not tell you what to do. In such situation, I, as an arbiter, would rule to correct that move nonetheless without penalizing the player who made it (i.e. you) since it was the opponent's responsibility to make a claim.

Current Laws of Chess are here.
> 2 votes

# Answer
It depends whether USCF or FIDE rules apply, and may depend on whether an illegal move was previously claimed.

Under the USCF blitz rules listed in my *US Chess Federation's Official Rules of Chess 5th Edition*, an illegal move results in a penalty of two minutes. There is a variation listed, however, where an illegal move results in forfeiting the game. In this case, capturing the opponent's king is listed as a way of claiming a win, rather than being its own illegal move.

The FIDE rules changed for 2018. It used to be that in blitz, an illegal move would allow the opponent to claim a win. However, this rule was changed, and now blitz is similar to normal chess in that a *second* illegal move by a player will result in a forfeit, and the first one merely results in a penalty.

As for which player can be penalized, it seems to be the player who took the king. See rule 1.4.1, which says "'capturing' the opponent’s king is not allowed." See also this article in which an arbiter says "As far as I can see, the player who completed the first illegal move is now entitled to claim the illegality." However, this article is from 2006 and isn't quite an identical situation; I can't guarantee that an arbiter today would rule the same way.
> 0 votes

# Answer
If the opponent presses the clock he has finished an illegal move and you may claim a win. If he does not press the clock he may claim a win because of your illegal move.
> -1 votes

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Tags: rules, kings, blitz, captures, illegal-move
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# Question
Title: How many moves is it possible to win in?
I was wondering what is the minimum number of moves it takes to win (checkmate) as I would like to accomplish this in a game of chess.

# Answer
> 2 votes
That's very, very, very dependent on your opponent. There really is no number you can give for a definite way to get a "auto-checkmate" (if that's what you're looking for) as every opponent has different preferences and playing style. Like @Scounged stated, black can win in two moves. For white, the technical fastest way to win is in three moves (here's one variation: 1. e4 f6 2. Bc4 g5 3. Qh5#) but again, your opponet probably isn't that bad. A very popular fast checkmate against beginners is known as "Scholar's Mate" or more commonly known as the "Four Move Checkmate". It goes something like this: (1. e4 e5 2. Bc4 Bc5 3. Qh5 Nf6 4. Qxf7#).

Now of course, every chess game is uniqiue to it's own. There is no definite number of turns it takes to get a checkmate. On average, they say that it is 40 moves.

If you would like to practice recognizing checkmate patterns and opportunities, I would suggest going to Chess.com or Chessable.com as they have quite a wide variety of material to improve your chess skills.

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Tags: winning
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