Has anyone used the Anki decks to learn tactics? I'm trying to learn how to build a deck in Anki so that I can improve my play by creating positions that I need to learn and by improving tactics. I'm looking for a guide on that process.

Well, what exactly do you want to know? The essentials are very simple: Have a "front side" showing a tactical position and a "back side" showing the answer. For the former you can just use images taken from scans. But there's also a note type available for Anki which lets you store positions in FEN notation. Search for "chess" on AnkiWeb to find it. This method is more memory efficient (and in some cases looks better), but might require a little more work than images, unless you also have the puzzles in e.g. PGN format.

I started out as an absolute beginner a little less than a year ago. I'm still a beginner and at the very bottom of food chain in the chess club I joined recently, but compared to from where I started I have improved a lot.

In my informed opinion spaced repetition in learning chess aims at pattern recognition. In other words: It's not about actually memorizing the solutions (so don't bother creating very short repetition circles), but developing an intuition for where possible solutions might be. In effect, though, it trains tactical intuition more than calculation. So I find that I need to compliment my Anki training not only with actual play, but also with solving composed mate-in-2 puzzles that I set up on the board to improve my board vision and calculation ability.

The specifics of what types of puzzles/questions are suitable depend on your level of play. As always with spaced repetition the cards should have clear, unambigous, easy to state answers. Though what exactly constitutes a "clear, unambigous, easy to state answer" probably differs from person to person and today I find solutions clear that were confusing to me a year ago. That being said, at my level basic tactics still work best. I gave up on creating more strategic cards for now, until my abilities have improved.

I guess that, since this is about pattern recognition, it matters what book you are using. I'm using Susan Polgar's tactics book for tactical motifs and the mate-in-two puzzles from L. Polgars 5000-something book for piece-interaction, mating patterns etc. Since solving puzzles on your smart phone is a great way to pass the time in the subway, I also have a deck with beginner puzzles from the 'Manual of chess combinations': unlike with the other two, I don't put any pressure on myself to go through this deck every day, but use it only when I want some 'extra chess'.

Anki help you to review and to keep in your memory tactics and other things, but for learning you need to work, after work anki is the tool.

Best regards.


What are the reasons why I should not try to take a Knight with my Bishop if it'll result in doubled pawns? For instance, in the Ruy Lopez, after

[FEN ""]
1. e4   e5
2. Nf3  Nc6
3. Bb5  a6

why shouldn't I take the Knight?

4 Bxc6 dxc6

Now Black has a doubled pawn.

It isn't a very popular line of play, which is why I think I shouldn't play it; but as to the principle, is it because I'm opening up Black's game?  I don't see any significant advantages/disadvantages for either side.

This is a variation that was played fairly frequently, but it has been more or less worked out to a draw, so it is less common at the top levels now.
The Ruy Lopez is a very concrete opening, and the capture on c6 has to be carefully considered as it relates to the exact position.
In terms of opening principles, you're giving up a bishop for a knight in an open position.  If you could take the pawn on e5, it might be good, but the pawn is protected via the tactical shot 5.Nxe5? Qd4! when white has basically given up the two bishops for very little compensation in a wide open position.
Another downside to Bxc6 is that the black's light square bishop is developed by dxc6, allowing it to come to g4 without waste of time.  Indeed, one of the most critical lines continues 5. O-O Bg4 6. h3 h5 when black is offering a piece for attacking chances along the h file.
With all of that said, this is a very common motif in the Ruy Lopez (Bxc6).  The pawn structure after d4 and exd4 is very good for white.  If all of the pieces were traded off, white would win the king and pawn endgame by making a passed pawn on the kingside and black cannot make a passed pawn on the queenside.
There are also many cases when spoiling your opponent's pawn structure is very good.  For example, if black has castled kingside, and a bishop can take on f6 and force ...gxf6, this is almost always good for white.  The king becomes very exposed with the g file open.  In the Spanish Four Knights, one player or the other will very frequently take on c6 or c3.

The knight pin by Bg4 is annoying. Playing h3 costs a tempo in an open game.


How does Allie's search algorithm work? Allie is a strong engine that's looking competitive with the top ones (Leela Chess Zero and Stockfish). It's supposedly based off AlphaZero, but works differently. As far as I understand it, the most important difference is the search algorithm. The author said in a March 2019 interview that:

  AT: To begin the tournament, Allie will perform MCTS based search with absolute fpu where new nodes start off with win pct of -1. The search is modeled after Deepminds paper’s. As I said above, I’m hoping to switch to AlphaBeta for the long term direction of the project. I’ve experimented with many, many ways of doing this with the networks generated by the Lc0 project and I think I’ve hit upon a way to achieve the depths required to maintain ELO level with MCTS based search, but it is not ready yet. In the future, I imagine we’ll see a lot of experimentation with different variations of search (mcts, ab) + eval (handwritten, NN) in computer chess engines. Hoping to be a part of that and to contribute to the shared pool of knowledge.

(Emphasis mine.) As of time of writing the Allie Github page says:

  Well, I was inspired during the original CCC to see if you could pair traditional Minimax/AlphaBeta search with an NN. This is still her main purpose and the focus going forward. However, the initial versions were using a similar pure MCTS algorithm as Lc0 and AlphaZero. The current versions of Allie use a modified hybrid search of Minimax and Monte Carlo.

I don't understand what "modified hybrid search of Minimax and Monte Carlo" means. Can someone explain? I know what each of these terms mean, but I don't understand the combination.

Allie's search is a combination of MCTS and Minimax. The MCTS is very much like you would find in AlphaZero or LC0 as it was taken from the same papers. In addition to MCTS, Allie also does a minimax based backup of the tree whenever a new MCTS batch is evaluated by the NN. This minimax backup is then used to modify the Q values of the nodes in the tree that were either 'min' or 'max'. This modification is a further averaging of the MCTS based backups.

So:

Allie uses MCTS for playouts and for back prop in much the same way as A0 and Lc0
Allie also does a minimax-based back prop to supplement that mcts based back prop

I've also tried many, many, many, different ways of adding newer AB/Minimax to the algorithm, but so far nothing that has successfully gained elo over the above. Finally, I'll note that in all of my testing of Allie (pure MCTS) vs Allie (MCTS+Minimax) the latter has scored significantly higher so I am confident that it does improve elo at least in self play.

UPDATE:

Since I wrote this, the Allie minimax backup has grown more complicated. Now, in positions where the best candidate move is a terminal node Allie does a pure minimax based backup with no mcts averaging. If the best is proven best among all of its siblings, then the parent is also made terminal and assigned the inverse score of the best child. If the best is not proven, then it still does pure minimax backup, but the parent continues to be expanded and if a sibling becomes best it switches back to the combination of minimax+mcts backup. Finally, this is all kept track of for transpositions too.

“Minimax” means pick the move which minimises the value of the opponent’s best possible response. If the search space was small this can be applied recursively to essentially solve the game.
However chess is too big, so one can’t search the whole space. The program is picking a bunch of different directions randomly (aka Monte Carlo) and finding the minimax over all of these. There is some secret sauce the designer is glossing over here, hence “modified hybrid”.


Why is ...e5 dubious here? [fen ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5?!

Why is ...e5 considered dubious for Black here, although it is considered sort of a refutation after the move 5.f3?! e5!

What's the big difference? If it is strong after 5.f3, it shouldn't be so bad after 5.Nc3, the pawn structure is the same.

The problem with e5 is that after 6.Bb5+ white will be able to play the manoeuvre Nf5-Ne3 which will result in an iron control of the d5-square. (Without Bb5 the knight on f5 could be taken by the Bc8).

The difference to the 5.f3 line is, that f3 doesn't control d5, so when the knight lands on f5 the counterstrike d5 will be possible.

[fen ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5?! 6. Bb5 Bd7 7.Bxd7 Qxd7 8. Nf5


Why does it seem that one drops more rating points when losing than gaining when winning? It seems that when one loses a game against a compatibly rated opponent, the (USCF) rating point decrease is more significant than when one scores a win.

For example, between two 'C' players, losing an over-the-board game may cost a player 12 points, whereas wining, the increase in rating is 7 points.

This is an odd phenomenon in the Elo system. Is there an explanation?

I suspect it's a result of you not really knowing the rating of the player you're playing. Posted rating for a player in a tournament is typically already out of date. You can see it in more detail by checking the actual rating report of the event you played in (http://www.uschess.org/datapage/event-search.php) and you can see what the real rating of the player you played was at the start of the event. Keep in mind it changes with every round.

ELO ratings is all about statistics. When you win against a weaker player you gain less points then you lose when you lose against that player. You can also lose points when you draw against a weaker player.


Weighted adjustment for relative Elo I was looking at my biggest upsets the other day and realized that the result was unsatisfying.  Most of them were 500-600 point upsets when I was still really low rated (i.e. 800 beating a 1300), while the upsets I consider the greatest have been the 150-200 point ones scored as an A player or expert.  Similarly, it would be a much bigger upset if a 2650 were to beat Levon Aronian than it is for a 1500 to beat a master.  It seems like the higher ratings go, the greater the points matter - a 100 point difference matters a lot more the higher up you go.

Can anyone come up with a weighted or logarithmic way of representing Elo ratings on some sort of scale so that this is accurately represented and players can be compared in a consistent manner, or does such a scale already exist?

I think the phenomenon that you're describing is due to variability in play at lower levels.  Elo is defined based upon the statistical likelihood that one player will beat the other.

Here is the exact formula to get the expected score for a player (rating = Ra) vs an opponent (rating = Rb):

This means that an 800 player is theoretically as likely to beat a 1000 player as a 2200 player is to beat a 2400 player.

Obviously this is not the case because at the lower levels, there is a much higher variance in the results.  This difference is captured quite well in the Glicko Rating System.  Basically, a player has a rating as well as a ratings deviation (RD) which represents how well established a player's rating is.  So in your case when you were rated 800, most likely you were closer to 1100 or 1200 strength but your rating had not yet caught up to your strength.  It is one of the fundamental flaws in all rating systems that the rating always lags the strength.  If the USCF used the Glicko system, then these early wins would have resulted in a far greater rating jump than actually happened, and your opponent would also have lost fewer points.

So to summarize, while the rating systems are not perfect and your strength will frequently be above your rating, an 800 beating a 1000 and a 2600 beating a 2800 are both equally likely from a purely mathematical standpoint.

The weakness in the Elo rating system is that it relies on "scoring", that is, replacing trinomial chess game outcomes with binomial "scores" (win=1, lose=0, draw=1/2). Scoring causes some game outcome information to be lost. I made an empirical measure of the information loss and found it to be significant. I have proposed a two-dimensional measure of performance that is more accurate because it contains more information.


A first book for a chess beginner I am thinking about getting my first chess book. After making a bit of research, people recommend to not worry about opening and endings and start with a primer on general strategy. That description lead me to a book called "Logical chess: Move by move" by Irving Chernev, I was wondering if this is an appropriate book for this matter, or is there a must-own bible for the beginner that I missed.

For more information about my level, I pretty much just played chess online for a couple of months, and I would like to get a bit more serious, and start improving my game by doing more than just playing.

Edit: Following the advice of Mark Goodwin, here comes my best game, according to Stockfish

[FEN ""]

1. d4 e6 2. e4 Bb4+ 3. c3 Be7 4. Nf3 Nc6
5. Be2 h6 6. O-O d6 7. Be3 a6 8. c4 Bd7
9. d5 Ne5 10. Nxe5 dxe5 11. Nc3 Nf6 12. Rb1 O-O
13. Qc2 c6 14. Rbd1 cxd5 15. cxd5 exd5 16. Nxd5 Nxd5
17. Rxd5 Rc8 18. Qd2 Bc6 19. Rxd8 Rfxd8 20. Qa5 f6
21. Bb6 Rd7 22. Bg4

I didn't meant to 12. Rb1, was a mouse slip, although I wanted to do Rc1 which, according to Stockfish again, isn't much better.

You might want to post your best game here (cut and paste the pgn is sufficient). There are many different stages of 'beginner' in chess.

Anyways, what I suggest you do is to:

1) Keep playing every day. Experience is king.

2) Learn basic opening principles - you do not want to get caught out with your king in the centre, your pieces sitting on the first rank, or your rooks dusting off in the corners.

3) learn all the basic mating patterns - what good is being up two pieces if you cannot finish him off?

4) Do chess tactics daily, without fail - chess24 has a pretty good chess tactics trainer and it adjusts to your level. You will lose games because of tactics more than anything else. You will win all your games because of tactics. I've been playing since 1973, and to this day, I do tactics every day.

5) record and review all your games (if you are playing online you are all set - all servers record the game for you), and maybe once a week or as frequently as you see fit, review your losses and understand where you went wrong. Make some friends online on your chess server with people who are better than you and ask them to review some of the games with you. This is the most single valuable thing you can do to improve your game.

6) Ignore all opening advice and play what you like. If you fail in the opening, understand why and fix it (books, better players, online resources, chess engines, etc.) If you really want to develop your chess openings at such a nubile stage, then Chessable is a good place to start and it's free, but unnecessary.

7) acquire a basic chess strategy book - someone mentioned Ludek Pachman's book but that might be too advanced, I think. You may grow into it, however. Jeremy Silman's Imbalances book(s) are popular. There are many.

8) Lastly mentioned, but not lastly important, learn the basic endgames necessary.

Good Luck and Good Chess!

1)Judgment and Planning in Chess by Max Euwe

2)The Chess Player's Battle Manual by Nigel Davies

The above books would be fantastic if you can read chess notation


Which gambits have been most successful? Besides the Queen's Gambit (which isn't really a gambit anyway), which gambits have been most successful as far as winning percentage and usage at high levels of play?

According to these statistics from 4 million games, the Marshall Gambit of the Semi-Slav defense is the most successful with 58.4% wins. I only counted gambit openings that had more than 1000 occurrences in the database.

The least successful gambit appears to be the Latvian Gambit with only 41.1% wins.

Note that since the database does not discriminate against older games, the statistics may not necessarily reflect the possible outcome of an opening if it were played today.

According to Stockfish, the best is the Fried Liver Attack (+1.57), and the worst is the Latvian gambit (+1.61) for black, the worst is not the Halloween Gambit, although it's almost there.


Vienna Gambit vs King' Gambit The Vienna game/gambit goes as 1. e4 e5 2. Nc3 .. 3. f4...
Why is this considered much more solid/sound than just the King's gambit. It doesn't seem to me that the extra 2. Nc3 thrown in is doing anything?
Additionally, how is the Vienna gambit different from the Vienna game when 3. g3 is played? 3. g3 followed by fianchetto of the f1 Bishop seems to give more semi-open positions. So it seems to me that 3. f4 and 3. g3 would lead to very very different types of games and should be considered two different openings entirely.

The inclusion of 2. Nc3 ahead of f2-f4 is most significant.
Consider 1. e4 e5 2. f4. Does 2. f4 aid White's development? Does 2. f4 make a threat? In both cases, no. 1. e4 e5 2. f4 isn't a threat because if we gave White an additional move for 3. fxe5, then 3...Qh4+ ruins White's day. That's the first reason for 2. Nc3: by guarding e4, it means f2-f4 will make a genuine threat of f4xe5 because following ...Qd8-h4+, ...Qh4xe4 is out of the picture.
The other reason for 2. Nc3 is its influence on d5, given that when White plays f2-f4 as a means of getting the upper hand in the center (by deflecting the e5-pawn, or capturing it), Black's simplest counter in the center is ...d7-d5. However, it does not at dissuade Black from  2. Nc3 Nf6 3. f4 d5, by far the most common continuation.
If White wants to play this flavor of Vienna, he has to like the positions that result from 4. fxe5 Nxe4 5. Nf3. If White really wants to shut off ...d7-d5, he can postpone f2-f4 for still another move with 3. Bf1-c4. That invites the craziness of 3...Nxe4, which is a whole 'nother ballgame.
2...Nf6 3. f4 d5 is most common, but say Black lets White carry out his plan. Suppose 1. e4 e5 2. Nc3 Nc6 Then 3. f4 exf4 4. Nf3. Black is willing to go for this because the knight on c3 is sort of misplaced!
Again, consider the immediate 2. f4. 1. e4 e5 2. f4 exf4 3. Nf3
(3. Bc4 was the choice of Fischer and Polgar, allowing 3...Qh4+, for whatever that' worth. Keres played 3. Nc3 in his brash youth, after which 3...Qh4+ is more meaningful because White's flight is Ke1-e2 rather than Ke1-f1. Steinitz tried the most thematic 3. d4, but 3...Qh4+ compels 4. Ke2 in that case, also. I wrote an entire book on 3. h4.)
3...g5 4. Bc4
(4. h4 is more positionally logical, though 4. Bc4 is equally popular, partly because some players with Black will choose 4...g4 5. O-O gxf3)
4...Bg7.
4...Bg7 is a huge move, mostly because it guards the h8-rook,. so 5. h4 doesn't force ...g5-g4, but can be met by 5...h6 6. hxg5 hxg5 7. Rxh8 Bxh8.
And since ...Bf8-g7 is such a useful move for Black in those King's Gambit Accepted positions, White would rather leave c3 open for the pawn to support d4 (but that Vienna knight prohibits that, and is therefore somewhat misplaced — how ironic).
About 1. e4 e5 2. Nc3 plus 3. g3. There White is keeping f2-f4 in reserve for a long time, after his kingside development is complete (the Bg2 influences Black's main counterattack square d5 from a distance), and the queenside has d2-d3, after which f2-f4 will have the Bc1 behind it and the  Pg3. These positions are actually very quiet because the pieces don't come into contact as quickly (obviously g2-g3 plus Bf1-g2 is less combative than Bf1-c4 which invites a fight with ...Ng8-f6 plus ...d7-d5). In many of those games, White kept f2-f4 in reserve until it most safe, and then goes on with f4-f5 to take all the kingside space (presumably while Pe4, Nc3, and Bg2 keep Black under wraps).

To try to avoid the Albin.
If black plays nf6 he can still counter with d5 and avoid a pure KG.


Which piece should I move and where should I move it when playing against black in chess when I have the first move of the game? What is the first piece I should move as a novice chess player when beginning the game on the white side as a defensive strategy?

There is no magical move that will solve your opening problems. But if you learn opening principles you can find the correct moves for solving your problems your own.

I recommend you to read this: http://www.chess.com/article/view/the-principles-of-the-opening

I also found this video quite entertaining: https://www.youtube.com/watch?v=lNO9KCloLRE

Also check these opening traps: https://en.wikipedia.org/wiki/List_of_chess_traps

I have a strategy that works like this:

G1F3
B1C3
H2H4
A2A4
H1H3
A1A3
E2E4
D2D4
F1E2
C1D2

Hope this helps.


Is this endgame winnable for white? (Knight vs two connected passed queenside pawns) I would like to know if this endgame is winnable for white. Black to play.

Any help would be greatly appreciated :)

EDITED IN RESPONSE TO COMMENT MADE BY MEMBER DagOskarMadsen:

Endgame remains a draw, but there was a mistake in my analysis-I hereby thank member DagOskarMadsen for pointing it out. I have updated my answer with the proper drawing move, and have left the bad variation as a sideline and marked it with ?? so it can be noticed more easily. I have also more thoroughly analyzed other sidelines which can be seen in my updated comments-some of the variations are highly instructive. I again apologize to viewers of this post for my mistake.

FINAL EDIT:

I just had a hunch that Black can make a draw based on his strong king-so I had to try finding a solution again. I will post my findings in the section with variations. Also, I will leave the old variations so previous comments will not become useless.

EDIT:

Edited analysis and the final conclusion in response to member's DagOskarMadsen comment.

In endgames raw calculation strength comes secondary-the most important skill is to see "the big picture" and your first task is to make a long term plan of action. To do that you must analyze the position thoroughly. Only after you have made a plan, you can verify its correctness with raw calculation of lines. So let us start analyzing the position above:

The most obvious characteristic is that White has a knight for a two pawns. However, that knight is so badly positioned. It blocks Blacks pawns, but it is a weak knight rather than good one. Why? What is the difference between this knight and a good one? A good knight can block the pawns and support the execution of the overall plan-this knight can not do that since Black's pawns will queen if he leaves them unchecked. Whites king is weaker than Black one. Whites g5 pawn has achieved maximum efficiency-tying down the entire Blacks king side, but e3+f2 pawns are weak and are restrained by one Black pawn.

As for Black, he has achieved maximum efficiency on the queen side, he can not advance further since he has no entry points. His e4 pawn has achieved maximum efficiency as mentioned before ( this pawn also takes away d3 square from the White king which is important for Black's defense-it reduces Whites options for zugzwang, disables White king from penetrating to the king side, and disables White from reorganizing e and f pawns for proper defense ). Black pawns on a4 and b3 tie down to defense both king and knight and have achieved maximum efficiency at this moment.

Black's plan:

Black has advantage on the queen side, but can not capitalize on it. In this situation it is usual to trade this advantage for the new one-Black will trade queen side advantage ( a and b pawns ) for the initiative on the king side.

White's plan:

White needs to improve his knight's position in order to win. Knight should stop Black's counter-play by cooperating with his pawns, allowing king to take all of the Black's pawns. Ideally, White will block the entire position and use zugzwang to take Black's pawns one by one.

The "Big Picture":

White will need to remove black a and b pawns in order to be able to free the knight to execute the above plan. To do that White will lose 4 tempos-he will need to play Kb4+Kxa4+Kb3+Kxb2 since Black will surely play b2! as soon as he loses a pawn. Why? Because if he does not, White will lose only one move to take the b pawn by playing Kxb3 but after b2! he will need two moves to do that-Kb3 and Kxb2. In this position every tempo counts since both sides race to reach the king side first. We also know that it is Black's turn to move so this adds another tempo. With 5 tempos ahead, a stronger king, pawn weaknesses and holes on the light squares-especially one on f5-we can safely evaluate that Black will be able to fulfill his plan- but whether White will have time to improve knight's position and to win the game requires precise calculation and a strong endgame technique.

The calculation:

Now is the time to try and verify our conclusions-here are the variations:

[FEN "8/5p1p/6p1/2k3P1/p3p3/1pK1P2P/5P2/1N6 b - - 0 1"]

1...Kd5 2.Kb4 Ke5 3.Kxa4 b2! 4.Kb3 ( 4.Nd2 Kf5 5.Kb3 b1=Q+! 6.Nxb1 Kxg5 7.Nd2 Kh4! 8.Nxe4 f5! 9.Nd2 Kxh3 10.Kc4! Kg2 11.f3 (11.f4 h5! 12.Kd3 Kf2! 13.e4 fxe4+ 14.Nxe4+ ( 14.Kxe4 h4 15.Nf3 h3 16.f5! gxf5+ 17.Kf4!! Kg2 18.Ke3!= ) Kf3 15.Nf6! Kxf4 16.Nxh5+!= ) h5! 12.e4 fxe4 13.fxe4 h4= ) Kf5 5.Kxb2 Kxg5 6.Nd2 Kh4! 7.Nxe4 f5! 8.Nf6 ( 8.Nd2 Kxh3 9.f3 ( 9.Kc3 h5 10.f3 h4 11.e4 fxe4 12.fxe4= ) ( 9.Nc4 Kg2 10.Kc3 Kxf2 11.Kd4 h5 12.e4 fxe4 13.Kxe4= ) 9...g5!! ( 9...Kg3?? 10.Kc3 h5 11.e4 fxe4 12.fxe4 +-) 10.e4 fxe4 11.fxe4 Kg4= ) h5 9.Nd5 ( 9.f3 Kg3 10.e4 fxe4 11.fxe4 Kf4 12.Kc2 Ke5 13.Nd7+ Kxe4= ) Kxh3 10.Nf4+ Kg4 11.Nxg6 Kf3 12.Kc2 Kxf2 13.Kd3 Kf3=

14.Kf3 is the only move that draws.

The point is that in all variations Black is able to create sufficient counter-play with the h-pawn which results in White being forced to give up knight for him ending in a drawn pawn end game or Black simply manages to exchange all pawns.

All the positions were checked with tablebase from this site, so when I put =, it means that I have consulted the tablebases as well. I also fully stand behind my evaluations, so if anybody has a question or a comment feel free to ask/comment-I will respond as soon as possible.

The above sample is good enough to give the reader an idea how to save the game. The rest is omitted in order to preserve space.

/********* BEGINNING OF THE OLD POST ***********/

This was the old calculation and is left for the sake of not making previous comments ( especially one made by the member DagOskarMadsen ) useless. Also, I believe that the variations are highly instructive.

[FEN "8/5p1p/6p1/2k3P1/p3p3/1pK1P2P/5P2/1N6 b - - 0 1"]

1...Kd5 2.Kb4 Ke5 3.Kxa4 b2! 4.Kb3 ( 4.Nd2 Kf5 5.Kb3 b1=Q+! 6.Nxb1 Kxg5 7.Nd2 f5? +- 8.f3 exf3 9.Nxf3+ Kh5 10.Kc4 g5 11.Nd4!+- transposes ) Kf5 5.Kxb2 Kxg5 6.Nd2 f5? +- 7.f3 exf3 8.Nxf3+ Kh5 9.Kc3 g5! 10.Nd4!+- Kg6 (10...g4 11.hxg4+ fxg4 ( 11...Kxg4 12.Kd3+- ) 12.e4+- )( 10...f4 11.exf4 gxf4 12.Nf3+- ) 11.Kc4 Kf6 ( 11...g4 12.hxg4 fxg4 13.e4 Kg5 ( 13...g3 14.Kd5 g2 ( 14...h5 15.Nf5! g2 16.Nh4+) 15.Nf3+- ) 14.e5 g3 15.Kd5 g2 ( 15...Kf4 16.Ne2+! Kg4 17.Nxg3+- ) 16.Ne2!+- ) 12.Kd5 h5 13.Kd6! g4 ( 13...h4 14.Nf3 g4 15.hxg4 fxg4 16.Nxh4 Kg5 17.Ng2! Kf5 18.Kd5 g3 19.e4+ Kg4 20.Kd4! Kf3 21.Ne3+- ) 14.h4!

with decisive zugzwang.

There is not enough space to show all winning moves entirely so I have stopped my analysis as soon as position arising can be solved with tablebases. Hopefully you will understand.

/******* END OF OLD POST ****************/

CONCLUSION:

  Is this endgame winnable for whites?

No, it is winnable for White.

Again, I apologize for giving you false information, but I believe that the end game is highly instructive and just could not leave it without thorough analysis.

Hopefully this answer will help you to learn something new-I know I certainly did!

Best regards.

The answer would depend on the side to move.
If it is white's turn, white wins with Nd2.
If it is black's turn, it is a draw, the black king picks up the loose g5 and h3 pawns and then the remaining material in insufficient for a win.
It is very dangerous to decide on games outcomes without knowing the side to move.
There are positions in which, depending on the side to move, each player can deliver his opponent mate.


How do opening books in engine chess work? I thought opening books were just big compilations of opening moves that engines have access to, and they choose at random which move to play from the list of moves that the opening book says is good. However if this is correct, I don't see how videos like this make sense. How can an opening book "beat" another?

Am I understanding opening books wrong? What are they exactly, and how do they make an engine stronger (if they actually make the engine stronger)?

Your understanding is more or less correct, an opening book is a large collection of positions and what are the "book moves" in that position. I don't know if engines typically choose at random if there are multiple moves in the book for a given position or if they do something more complicated, but that doesn't matter much for your question.

  How can an opening book "beat" another?

It can contain better moves, and more of them, and they could even be better tailored to the specific opponent!

To figure out which is better, you let the same engine play against itself, with one side using one opening book and the other side the other. If you take care to have each book play white as often as black, you can see in the end which book had a higher score against the other book.

For instance, an opening book could contain a line somewhere that actually is not as good as the author thought at the time of putting it together, and the other book chooses to go for that position as the other side and it leads to a win for the engine.

Or one book is "done" after 15 moves after which the engine is on its own, but the other book still has several moves coming up after it on which the engine spent far more time on while creating the book than it could during the actual game.

Or the author of the opening book for engine A knows that engine B is worse at playing certain positions from the French, and he chooses to put moves into the book that causes A to go for those positions whenever it has the chance.

Or an opening book author spends days analyzing a certain position in an opening, and finally figures out that there is a way to force a good position for white there, and he adds it to the opening book. Engines with books that still allow that position to come up will have a bad time there.

And so on, opening books are in the end created by humans (with heavy use of engines) and the same arms race is going on there as between top human players.

A better book gives better lines and moves for an engine. For example, if you were to construct a book based on beginner games (no more than 1200) on lichess, it would not perform well.


Which interface protocol should I implement for my chess engine? I am writing a chess engine in C++ https://github.com/RomainGoussault/Deepov.

I know there are several interface protocols out there (UCI, Winboard protocol, etc) and I don't know which to implement. I would like one that:

enables my engine to play online tournaments
has several GUI for Linux, Windows and iOS
has some sort of documentation

Thanks

There're only two protocols - UCI and Winboard. Winboard is an old protocol and not really being used nowadays. Crafty is the only major engine still supporting the Winboard protocol, but it's only because the engine is also very old. UCI is a newer protocol developed by Shredder, and is used everywhere - Windows, Macs, Linux, Android, iOS etc. UCI is really the only protocol you should consider.

UCI is supported everywhere
Every chess GUI other than xboard supports UCI, such as, Chessbase, Scid, Arena etc. Even xboard can connect to a UCI engine by something known as Polyglot.
UCI documentation is at http://wbec-ridderkerk.nl/html/UCIProtocol.html

Winboard has more or less obsoleted because the protocol is more complicated than the cleaner UCI. Winboard is a stated protocol, it means the engine state depends on the previous iterations, whereas UCI is easier to deal with as you only have to supply with your current FEN or a move-list.

Most GUI support engines either in UCI or Winboard, UCI becoming more of a standard and popular these days. But, typically if you want your engine to be easily pluggable to any GUI (in Windows or Linux), then you should have an "exe" or executable which can be pointed to by these GUI programs. If you are building the engine using Java, then I am unsure how you would be able to convert this to an executable to be used by the GUI. The same thing applies to be able to play online tournaments. Even if you are planning to provide a web-service kind of interface for your engine, I don't think it can participate in engine competitions.


Computer chess endgame Again , this is an interesting position I need help to solve. In a game Stockfish vs Ethereal , Stockfish was ahead , but Ethereal could have found  refuge in the following endgame. Is the position winning for White anyway? Could Black steer it into a positional draw?
[White "Stockfish"]
[Black "Ethereal"]
[FEN "4b3/4N1k1/3R3p/r7/8/P6P/5KP1/8 b - - 0 1"]

I am unsure what version of Stockfish you were using so I ran analysis 12 times; 4 seperate engines for each version of Stockfish.

Stockfish 10 vs ( Ethereal , Komodo, LC0 , Stockfish 12 )
Stockfish 11 vs ( Ethereal , Komodo, LC0 , Stockfish 12 )
Stockfish 12 vs ( Ethereal , Komodo, LC0 , Stockfish 12 )

Results were Stockfish (white) at the end of 20+ moves, was in a stronger position in all 9 instances. Based off this, I would suggest black is in a losing and in a irrecoverable position. There is the potential for a draw but it appears extremely unlikely.
The best variation / playout that I saw, that had the best end position for black, was Stockfish 12 vs Stockfish 12. +-3.03 / 41 so white is decisively better.
Issue with engine games in these sort of positions are the gameplay is boring. That being said, I have attached it for reference though.
[White "Stockfish 12"]
[Black "Stockfish 12"]
[FEN "4b3/4N1k1/3R3p/r7/8/P6P/5KP1/8 b - - 0 1"]

1... h5 2. Rd3 Kh6 3. Kg1 Kg7 4. Rc3 Kf7 5. Nc8 Kf6 6. Nd6 Bg6 7. Kh2 Ra4 8. Rf3+ Kg5 9. Nb5 Kh6 10. Nc7 Ra5 11. Ne6 Bf5 12. Re3 Bg6 13. Rc3 Bf7 14. Nf4 Kg5 15. Ne2 Ra4 16. Rf3 Bg6 17. Rg3+ Kh6 18. Rc3 Be4 19. Nf4 Ba8 20. Ne6 Ra5 21. Nc5 Bd5 22. Nd3 Ra4 23. Nb4 Be4 24. Re3

From my experience with engine games this is going to continue on for some time. Eventually the Black h pawn and Whites a pawns will go (will likely also involve trading out the bishops somewhere ) , white with the pawn advantage will promote.

this would be tough to win OTB  with many ways to end up drawn
a computer might do it but I doubt it would be quick and easy


Why is there a craze of becoming chess grandmaster? Go to any online chess server, there are thousands playing and trying their best. These days there are even online coaches and titled players and people are ready to shed huge bucks for getting couple of hours sessions.

But given all this, I sometimes think: Why do people want to become a chess grandmaster or a titled player? What do I really get out of that? A high paid job? NO. A green card to the US? NO. Free sponsorship? PROBABLY NOT. A lot of money? NO (because once you become GM you have to compete with others similar to you).

Then why? Why is there a craze to become a chess grandmaster, or a titled player?

If anyone has a good answer and a accurate ones, please reply with good points.

Napoleon put it succinctly:
A soldier will fight long and hard for a bit of colored ribbon.

Just a couple of points:

It is the same reason that students love getting "gold stars," and why there are so many badges on StackExchange itself. There have been volumes written on the power of peer recognition.

In particular, chess titles (for the most part) are a direct result of chess achievement. FM, IM and GM titles are all well-earned. No matter how much we might not care for a person, we know that if they have a chess title, they earned it. A GM title is the highest formal title, and it serves to inform your peers (and often yourself) that a certain level of expertise was attained.

What do i really get out of that - a high paid job? NO - a green card to US? - NO - free sponsorship? PROBABLY NO - huge money? - NO (because once you become GM you have to compete with others similar to you)"

There is a craze of becoming GRANDMASTER because:

You can get a highly paid job.
You can get a green card to the USA.
You get free and good sponsorship.
4.You can also earn a lot of money through coaching, prize winnings, appearance fees, etc. (really).


Is this position a forced win for Black after move 14? In this Lichess game,

[FEN ""]

1.c4 e5 2.e4 d6 3.Nc3 Be6 4.Nf3 Nc6 5. d4 exd4 6.Nxd4 Nxd4 7.Qxd4 c5 8.Qd3 g6 9. Be2 Bg7 10.O-O Nh6 11.Re1 Ng4 12.Bxg4 Bxg4 13.e5 Bxe5 14.Nd5 Qh4 15. Nc7+ Kd7 16. Nxa8 Qh2+ 17. Kf1 Qh1#

After move 14 White is facing a serious mate threat from the Queen on h4, Bishop on g4, and Bishop on e5. White goes with 15. Nc7+ , forking the King and Rook, but ignoring the mate threat. After the rook capture, Mate in 2 was assured.

Could white have avoided this mate? By playing, say, Qg3 or h3? Or do both of these positions lead to wins for black, hence, white's strategy with 15 Nc7+ was to prolong mate and perhaps prod black into an unforced error?

The best move would have been 16. Rxe5, which entirely eliminates the mate threat, leaving white with a winning advantage.

r6r/ppNk1p1p/3p2p1/2p1R3/2P3bq/3Q4/PP3PPP/R1B3K1 b - - 0 16

Here, if black takes the white knight (16. ... Kxc7), 17. Bg5 wins the queen as Qh5 is met with Bd8+.

It is indeed a forced win for Black, partly due to White's choice to ignore the mate threat. White could respond better with 16.g3, thereby buying time and throwing Black off-guard.


Looking for a chess engine that instead of playing the best move randomly chooses among the best moves? Of course this should be subjected to some rules; something like "play any move that's not bellow 0,70 the best move", or something similar.
My idea is to use such an engine in order to play some unorthodox openings without needing an opening book.
For example, say I want to play some games as White trying 1.e4 e4 2.a3. I'm sure there are many good moves for black's second move, so I'd like the engine to "choose" from several of them, instead of always playing the best one.
Kudos if this behavior could be limited to a fixed number of moves -so you get some variety in the opening but you want it "full power" on middle and endgame.

There are few engines that are capable of such thing. One name that I can recall is the old Spark UCI engine by Allard Siemelink.
Very aggressive engine with twistable attacking parameters.
It has a feature called MultiPVMargin which enables you to set certain number difference between the PV (Principle Variations) measured in centipawn.
For example if your best calculated variation in certain position is measured as +1 for white and you want the engine to play something less "valuable" than that, you can set the MultiPVMargin to a 100 so that the engine looks for a different variation within the 100 centipawn difference.
You can find older versions of the Spark engine that are available for free download.
Hope this was the answer you were looking for!

I'm not sure what the question is.
https://www.youtube.com/watch?v=DpXy041BIlA is a video about 30 different AI styles.
Of course, like the early Chessmaster, you could limit the computer to only play within a certain range of evaluations.  Instead of choosing from X number of moves, the engine could store a list of moves with their evaluation and prune this list down to only the move which scored within 100 points of the best move and randomly choose from this list.
You could force the computer to randomly select from the top 3 moves, probably with a cutoff, to make the openings more entertaining.  You could add more flavor by having the computer switch to the best moves at certain moves/move ranges or after it falls below s certain evaluation.  The possibilities are endless.


Can someone describe a good/easy mental procedure to choose the best move here? This is kind of like magic to me. Once they show you it becomes obvious :) :(

Can someone point out a good/easy strategy that a player can mentally train/use to decide what is the best move here for black?

Note: Guys, there is a best move for black there can lead to a checkmate later. The goal is not to find it, but to come up with a procedure to find it so it can be applied to other positions.

I would say there are two tactical possibilities for black here:

1…Bxd3 2.Rxd3 Rxa4 3.Qxa4 Nxb2 wins the pawn back with a better position (the a3 pawn is now weak).
1…Rxe3 2.fe Nxe3 3.Qe2/d2 Bxd4 and the a4 Knight is hanging and the d1 rook is hanging with check … it still isn't over, in a game you should probably calculate further, but I'm to lazy to do that now.

There actually is an easy rule to find both of these tactical strikes:

Consider all captures!

Usually this rule is even broader: Consider all forcing moves! This includes captures, checks and attacks on stronger pieces.

Disclaimer: As with all rules this maxim has to be tempered by experience.

I guess there is none logical strategy to follow. You just need to try to calculate in your head somehow and use intuition.


A cool problem by Godfrey Heathcote I didn't get a thought of a better title :)

I am trying to solve a problem which is white to move and mate in 2 moves.

To be frank, I am not asking all problems here. On my own I solved more than 50 and stuck up in nearly 15 (don't worry I will not ask all here itself, I am still trying to solve them)

[FEN "8/qQ5p/3pN2K/3pp1R/4k/7N/1b1PP/8 w - - 0 1"]

Qxa7
if d4 then simply move the queen back to b7 (mate)
if black moves the bishop instead then simply Qxh7 (mate)


What does chess theory refer to? I hear some people say certain players only win because they know/memorized a lot of theory? I don't know the "official" term for these types of players but it makes me concerned because hopefully I'm not one of them. It makes it seem these types of players aren't good at chess or don't really use their head to play the game. Can someone clarify what this is all about?

Chess theory in this sense refers to opening variations / opening analysis. Every strong player has a repertoire of opening lines that he likes to play and in which he knows pretty well which moves are the best.

Some players analyse the opening exhaustively and try to find tricky lines before they sit down to play. This is helped by the fact that they can look up games of their next opponent in databases. These players occasionally win games just by following their home preparation.

But this is not something that should overly concern you. It's more of a grandmaster's problem. On the top level in chess opening preparation plays a big role. In amateur games it is usually easy to dodge any kind of special preparation by the opponent.

It is easy to look down on people who spend a lot of time learning opening variations by heart, but in reality spending time on the opening also improves your understanding of typical position, tactics and plans. If somebody wins a lot of games in the opening, this is never just due to reproducing learned lines with no understanding. Chess is too complex and diverse for that.

certain players only win because they know/memorized a lot of theory

That's just nonsense. Anybody who wins regularly does so because they know rather a lot of theory.

BlindKungFuMaster's claim that

  Chess theory in this sense refers to opening variations / opening
  analysis

is also nonsense.

Theory is a lot more to chess theory than just opening theory. Endgame theory is the most important part of chess theory. If you don't know any endgame theory then most of your games will be a matter of luck.

Do you know how to mate with king and queen against king? Yes? Then you know some theory. King and rook versus king? King and two bishops versus king?

How about pawn endings? Do you know when king + pawn versus king is a win and when it is a draw? How about king + rook + pawn versus king + rook?

Already we have touched on a lot of important theory. If you know this theory then when you are playing the middlegame you know what kinds of endgame you can aim for and win. If you don't know how to mate with king, knight and bishop against king then don't aim for this endgame because it is going to be a draw.

If you have an extra pawn in an endgame with just kings and several pawns and your opponent lets you swap off into an endgame where you have a king and a rook's pawn against his king and so it ends in a draw is that somehow unfair? Is this "somebody who didn't really use their head to play the game?" No, your opponent earned the draw by virtue of his superior theoretical knowledge. If you had the same knowledge you wouldn't let it happen.

Endgame theory is rather concrete. Middlegame theory is much more fluid. When does sacrificing the exchange give you a winning advantage? When are doubled and / or isolated pawns good? When are bishops better than knights? How about knights better than bishops? When is it OK to leave the king in the center? When is it better to castle? Again somebody who has a better understanding of these theoretical ideas will play better than somebody who doesn't.

As regards opening theory, if you don't know any opening theory you will struggle to get out of the opening against a good player. Opening theory isn't just knowing a set pattern of moves to safely develop your pieces it is also about knowing some of the typical plans that come out of the opening. It is all very well playing the first 10 or 15 moves according to "the book" but if you don't have some good ideas what to do next you will struggle to reach move 30 unless your opponent is in the same situation.


Is this endgame won for white? With the missing g and e pawns still on the board and a roughly symmetric position, I made a mistake that led to 17 moves of what I think of as quite difficult defense. My opponent walked into the following fork and then resigned.

 [Title "Game's Final Position"]
 [SetUp "1"]
 [FEN "8/5pp1/7p/1n1R3k/4PP1P/8/8/r3BK2 w - - 6 1"]

I know that I definitely would not have resigned in that position.

  Is the above position won for white?

Conceivably, black could play Kg6 and try to put together something like a fortress, or even play g5 immediately after Rxb5. However, I believe the correct continuation would be

1 ... Kg4 2. Rxb5 Kxf4 3. Rf5+ Kxe4 4. Rxf7 g5 5. h5, resulting in the position

 [Title "End of My Main Line"]
 [SetUp "1"]
 [FEN "8/5R2/7p/6pP/4k3/8/8/r3BK2 w - - 6 1"]

with black to move.

From tablebases (e.g. this site), I know that if I instead played 5. hxg5 and black responded with hxg5 then the position would be a draw. In fact, even if all three remaining pawns disappeared and it became my move, the position would still be a draw. Thus, white's strategy at the end of my main line presumably involves threatening/trying to win the pawn on h6, possibly after exchanging rooks.

(I don't know whether or not the "rook endgame" tag is appropriate, since there's also a bishop on the board.)

According to my analysis, it seems like a clear win. Black can't force the exchange of the remaining white pawn,  White has the Bishop of the appropriate color, and Black can't prevent White to improve the position of its pieces.

An important tactical finesse:

1..Ke5 2.Kg2 Rxe1 3. Re7+, winning the Rook.

Another important idea:

1..g4 2. Rf6 g3 3. Rg6! (3. Rxh6 g2+ 4. Kxg2 Rxf1 5. Rf6 =) 3..Ra5 4. Rg4+

and the g pawn falls.

(Note that 2. Kg2 is also possible, with the same idea as above.)

It should be a matter of time for Black to lose its remaining pawns, since the black King is cut off from them.  I can't offer any concrete lines, so perhaps I'm wrong here. But what I know is that

W: Kf1, Be1, Rh6, h5
B: Ra1, Kf5

is a win in the tablebases. It does not seem to be possible to prevent White to play Rh8 and h5-h6, after which the pawn is immune. As soon as it gets attacked by some Rh2, White has Rg8+, repeating the same tactical theme as above, or Bd2, protecting the pawn directly.

I've played some games with an extra Black pawn, and I have yet to save one game against Stockfish. One annoying bug of having a pawn on g4 is that black King can't move on g4.

I tried to put up Houdini 6.02 and a tablebase win is reached , albeit it is a mate in 48 !!! According to seven piece tablebases, White is even forced to give up the pawn toward the end but obtain a winning Philidor position! Yes , White wins , but has a lot of work to do.
Position WHITE Rook in h6 Bishop in g3, pawn in h6 , King in g2 BLACK Rook in d1 , pawn in g5 King in f5. BLACK to move : White mates in 48 moves.


What is the best continuation in this problem-h4 or Qd8? In the given diagram, I have two best ways to continue for white, which is the better option out of these two and why?

[FEN "2Q5/p1P2pkp/1p2p3/5p2/3P4/5P1P/P2q2PK/8 w - - 0 1 "]

1. Qd8 Qf4+ (1. h4 Qf4+ 2. Kh3 Qc1 3. Qd8 Qh1+ 4. Kg3 Qe1+ 5. Kh2! f4 6. Qg5+ Kf8 7. c8=Q#)2. Kg1 Qe3+ 3. Kf1 Qc1+ 4. Kf2 Qd2+ 5. Kg3 f4+ 6. Kh4 Qe1+ ( 6. Kg4 Qxg2 7. Kh4 Qg3+ 8. Kh5 Qg6+ ½-½) 7. Kh5 Qe5+ 8. Qg5+ Qxg5 9. Kxg5 1-0

Also would be interesting to see what line Houdini selects and how much will be the points for each of these two moves...

problem taken from here

4...Qd2+ in your main line is an error; instead Black should play 4...f4, after which he delivers perpetual check. White can try to play on with 5.Qg5+ Kf8 6.Qxf4 Qxf4 7.c8Q+ but that's still a draw. So 1.Qd8 does not work.

1.h4 enables White to escape from perpetual check, and wins.

in my Houdini views, you're already win in your normal play, and long way to be draw. h4 is already the best move.

Black should move 5. ... Qc3 rather than f4, f4 makes Black will lose inmate at maximum 2 possible combination moves.

BUT

rather lose, if I follow your inner moves Kg4 which give draw to White, in my Houdini views, I saw Black absolutely won.

as I can say, Kg4 move is just a curse for White because of force-move check.. ^^

[FEN "2Q5/p1P2pkp/1p2p3/5p2/3P4/5P1P/P2q2PK/8 w - - 0 1 "]

1. Qd8 Qf4+ 2. Kg1 Qe3+ 3. Kf1 Qc1+ 4. Kf2 Qd2+ 5. Kg3 f4+ 6. Kg4 Qxg2 7. Kh4 Qg3+ 8. Kh5! Qg6+  9. Kh4! Qh6+ 10. Kg4! f5+

  (0-1)


Queenless Imbalanced Middlegame I was analyzing the following position for one of the correspondence games that I am playing. In the position, white is up 2 pawns and with my limited understanding, I can't see any real compensation for black. I checked with Stockfish 10 at depth 29 and it evaluated the position as +0.63. I also checked with Komodo 13.2 which gives the position as +0.50 at depth 25. My question is basically on what is the compensation that black has for the 2 extra pawns or is there, in reality, no compensation and I didn't let the computer go into a higher depth.

Here is the position(Black to move):

[fen "r1br2k1/pp3pbp/6p1/4P3/5P1P/2N1P3/PP4P1/R1B1KR2 w - - 0 1"]

First, I don't think that there is any doubt that black has significant compensation, but clearly, black is still trying to hold this, not win it when talking two computers playing each other. I believe that between two humans, I would probably prefer black.

If you have an eval that says +.63 for white, but black is down two pawns, you have to realize that it means that black has roughly 1.37 in positional compensation.

White obviously has the two pawns, but black has the two bishops in a relatively open position, is ahead in development with the Rd8 already controlling the file, and h4 is a target that at the very least can be used to gain a tempo. Lastly, the g4 square is a wonderful spot for the Bc8, and helps control the open file. Also, the Rf1 is poorly placed, and the Bc1 currently does not have a bright future. One of the extra pawns, although I am going to trade it off, is currently doubled.

I analyzed this using a computer, and it is a VERY difficult position to get a handle on because so many of the moves are almost equal in the evaluations. In each case, what I did was let it get to a depth of 33-37 using Stockfish 11, and then I would advance the game by a move and force in the best move, and then let it get to a depth of 33-37 again, and so on. So, by the time I got to the 16th move of the variation, it was still looking 35+ ply ahead.

Here is the variation I found, and I have notes as to why the moves are being played. At the end, it is still only +.41, and despite the two pawns minus, it is hard to believe that white can win due to black's incredible activity, and the Kg8 will enter the game soon.

 [FEN "r1br2k1/pp3pbp/6p1/4P3/5P1P/2N1P3/PP4P1/R1B1KR2 b Q - 0 1"]

 1... f6 2. e4 Bg4 3. e6 (3. exf6 Bxf6 4. g3 Bxc3+ 5. bxc3 Rd3 6. Kf2 Re8 7. e5 Rc8 {and black is almost winning...f5 is already the only move so white can play Bf4 next defending g3.}) Bxe6 4. Kf2 Rd3 (4... Bg4 5. Be3 Rd3 6. Rfe1) 5. Rd1 (5. Be3 Bg4 6. Rac1 Re8) 5... Rxd1 6. Nxd1 Rc8 7. Nc3 f5 8. e5 Bf8 {Ba3 threat.} 9. Bd2 a5 {Idea a4-a3.} 10. Ke1 {To prophylactically protect the Bd2 after a4; Na4 Rc2} Bc5 11. Rd1 Be7 $1 {Only after a2 is undefended does this combined with a4 work.} 12. g3 a4 $1 13. Nxa4 (13. a3 Bb3) 13... Rc2 14. Rc1 Rxc1+ 15. Bxc1 Bxa2 16. Nc3 Bc4 $14 {Nd1 +.41.}

When you get those results from an engine that shows the game is essentially even while you see a two pawn difference then that means you do not fully understand the value of positions.

Black has the two bishops.
With Bg4 he will control the file his rook is on and finish his mobilization.

White will have problems getting his pieces onto useful squares.
The white bishop is bad as whites pawns block the bishop

Black will double rooks on the queen file threatening a pawn and the bishop if white moves it to d2.

p-f6 will be double edged freeing the black bishop but giving white a potential passed pawn in the late endgame. White could advance the behind 3 pawn to reblock the bishop.  black should wait on that move until rooks and  other bishop are deployed.

Overall it is a tough position with a lot  of play and white has a minimal edge that might matter between computers but not so much between people who actually do the moves.

If you are black  I suggest you offer a draw. Especially since you have been getting outside help by posting the question about an ongoing ICCF game online.  If you are white I suggest you offer a draw and hope black takes it.


Are two knights generally worth less than two bishops? A bishop and knight are considered to be about equal in value (three points each). There are even some (closed) positions, where a single knight is worth more than a "bad" bishop, although there are more positions where a bishop is worth a bit more.

But unless they're linked and extremely well placed, (e.g. d4 and e6), two knights are seldom worth more than six points. Some masters put the bishop pair at seven points in an open position because the two bishops together can cover squares of both colors, while moving faster. Does this make two bishops worth more than two knights?

I have read that a fairly open position, two knights may be worth no more than one rook (five points instead of six, or two and a half each). I've never heard this about two bishops. Does this strengthen the case that two knights are worth less than two bishops?

According to GM Larry Kaufman, who has worked on the chess engines Rybka and Komodo, and has done extensive database analysis of material imbalances,

The bishop pair has an average value of half a pawn (more when the opponent has no minor pieces to exchange for one of the bishops), enough to regard it as part of the material evaluation of the position, and enough to overwhelm most positional considerations. Moreover, this substantial bishop pair value holds up in all situations tested, regardless of what else is on the board.

although he goes on to note some exceptions. The whole article is worth reading.

Show me any instance where a bishop can protect the other bishop. Once an opponent decides that removing one of the opposition bishops is timely, the value of a bishop in my opinion drops one half a point.  Where as one knight in the end game is far more an aggressive tool than one bishop.  Knights are not bound to one color on the board.


Why does Stockfish give "score mate -7" for this position? I'm running Stockfish with MultiPV=7:

script: setoption name MultiPV value 7
script: ucinewgame
script: position startpos moves d2d4 g8f6 c2c4 g7g6 b1c3 d7d5 c1f4 f8g7 f4e5 d5c4 e2e3 b8c6 d1a4 e8g8 e5f6 g7f6 f1c4 a7a6 c4d5 b7b5 a4d1 c8b7 a2a3 e7e6 d5f3 c6a5 f3b7 a5b7 b2b4 c7c5 b4c5
script: isready
engine: readyok
script: go movetime 600000.0

When I look at the "multipv 7" lines, I see a strange evaluation at the end of the analysis:

engine: info depth 1 seldepth 1 score cp -74 nodes 463 nps 66142 time 7 multipv 7 pv e6e5 g1e2 e5d4 e3d4
engine: info depth 2 seldepth 2 score cp -74 nodes 1314 nps 187714 time 7 multipv 7 pv e6e5 g1e2 e5d4 e3d4
engine: info depth 3 seldepth 4 score cp -79 nodes 3193 nps 399125 time 8 multipv 7 pv d8c7 c3e4 c7a5 d1d2
engine: info depth 4 seldepth 6 score cp -106 nodes 6224 nps 622400 time 10 multipv 7 pv d8c7 g1e2 c7a5 d1d2
[268 lines omitted]
engine: info depth 31 seldepth 52 score cp -70 nodes 3472890690 nps 6622358 time 524419 multipv 7 pv e6e5 c5c6 a8c8 d4d5 d8a5 g1e2 e5e4 a1c1 b7c5 e1g1 f6e5 d5d6 f8d8 c3e4 c5e4 d6d7 c8c7 d1d5 e4c3 e2c3 e5c3 d5d6 c3b2
engine: info depth 31 seldepth 52 score mate 0 upperbound nodes 3666345467 nps 6585523 time 556728 multipv 7 pv d8e7 a1c1 a8c8 c3e4 e6e5 d4d5 b7c5 d5d6 c5d3 d1d3 c8c1 e1d2
engine: info depth 32 seldepth 52 score mate -7 lowerbound nodes 3696286819 nps 6601691 time 559900 multipv 7 pv d8e7 a1c1 a8c8 c3e4 e6e5 d4d5 b7c5 d5d6 c5d3 d1d3 c8c1 e1d2 e7e6
engine: info depth 32 seldepth 52 score mate -7 nodes 3992249349 nps 6653549 time 600018 multipv 7 pv d8e7 a1c1 a8c8 c3e4 e6e5 d4d5 b7c5 d5d6 c5d3 d1d3 c8c1 e1d2 e7e6
engine: info nodes 3992249349 time 600018
engine: bestmove d8a5 ponder g1e2

Why does the 3rd-to-last line give "score mate -7"?
I believe this is a lower bound due to pruning (as in my previous question), but the line does not say "lowerbound".
How can I extract the correct evaluation? I doubt the position is a mate in 7.

Full output is here.

[FEN ""]

1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Bf4 Bg7 5. Be5 dxc4 6. e3 Nc6 7. Qa4 O-O 8.
Bxf6 Bxf6 9. Bxc4 a6 10. Bd5 b5 11. Qd1 Bb7 12. a3 e6 13. Bf3 Na5 14. Bxb7
Nxb7 15. b4 c5 16. bxc5

Fist things first, I put the position into another chess program (Chessmaster, because I find it has the most reliable mate-search function) and told it to brute-force search for a mate. This is what it found:

So to answer one part of your question, no, there isn't a mate in 7 here.

That leaves the question of why you are getting the lines:

engine: info depth 32 seldepth 52 score mate -7 lowerbound nodes 3696286819 nps 6601691 time 559900 multipv 7 pv d8e7 a1c1 a8c8 c3e4 e6e5 d4d5 b7c5 d5d6 c5d3 d1d3 c8c1 e1d2 e7e6
engine: info depth 32 seldepth 52 score mate -7 nodes 3992249349 nps 6653549 time 600018 multipv 7 pv d8e7 a1c1 a8c8 c3e4 e6e5 d4d5 b7c5 d5d6 c5d3 d1d3 c8c1 e1d2 e7e6

I would suggest that the first of these is stating that as far as the engine has calculated, there is no mate in 7, hence the term lowerbound. The next line indicates that the engine is initiating a PV-search for a mate in 7.

Your largest issue here is the fact that you are using mutli-PV at 7. They often yield unreliable results, so I would recommend moving that down to 3 or lower. When I am doing serious analysis, I often keep it on 1 to maximize performance. After all, it takes more than n times longer per depth per PV.

Otherwise, the engine has no issue evaluating the position and does not find a false mate.


What are the techniques one can use to for chess board? What are the techniques one can use to keep all pieces   on a board ? It is like an n-queen problem

Is it a combination of n-queen

To address the edit to the question
If you're receiving the pieces in a random order and you don't have any information about future pieces, the way to arrange the pieces would be to give pieces the least amount of scope. For example, if I were to receive a queen on the first turn, I would place it in one of the four corners. Some more rules would be to keep knights close to each other and pawns stacked one on top of the other. All of these strategies are a bit obvious, but it's difficult to have a consistent strategy to use as there are so many potential combinations of pieces.

This seems to me as more of a programming question than a chess one, but it's interesting nontheless! After thinking for a bit, I would hypthesize that the best way to approach this problem would be to use the knights as a baseline. It's well known that the maximum number of knights one can fit on a board is 32 (simply placing them on all squares of the same color), therefore having this as your starting position is logical as this is the maximum occupancy you can have with an individual piece. This strategy extends itself to an N x N board.

Afterwards, I would use pawns as their attacking prowess is limited to forward diagonals of one square in scope. They can occupy every other column (not rows as this would be limited to 2, 4, and 6 if following conventional rules), and this will add N/4 more occupied squares for an NxN board. This generalizes to a total number of occupied squares to N/2 + N/4, or simply 3N/4 total occupied squares.

This is the result of around 5 minutes of consideration, so my algorithm may be flawed. I hope this helps answer your question!

Keep the pieces out of the center, on the sides.


What are the winning chances of every pieces? (6men egtb) Is there a site or document which shows what the winning chances are of every "Specific Pieces vs. Specific Pieces" endgame?

e.g. What are the winning chances of Rook & Bishop vs 2 Knights?

I don't know a single source tabulating the winning percentages for all 6-piece endings, but at least some amount of summarizing information can probably be found scattered throughout Nunn's Secrets of ... Endings series of books, which are essentially translations from tablebase to human-usable information. But there is a spreadsheet available from Tamplin's chess endgame site, 3-5 Man Results and Maximals, that contains the percentage winning statistics across all < 6-man endgames. A sample of the data:

Endgame     wtm(=)  btm(=)      wtm(1-0)    btm(1-0)        wtm(0-1)    btm(0-1)

KK          100.00  100.00      0.00        0.00            0.00        0.00
KBK         100.00  100.00      0.00        0.00            0.00        0.00
KNK         100.00  100.00      0.00        0.00            0.00        0.00
KPK         23.49   41.91       76.51       58.09           0.00        0.00
KQK         0.00    10.32       100.00      89.68           0.00        0.00
KRK         0.00    9.97        100.00      90.03           0.00        0.00

...

KRNKP       1.53    17.10       98.45       78.39           0.01        4.51
KRNKQ       41.12   19.71       35.44       2.10            23.43       78.19
KRNKR       63.29   93.60       36.63       3.24            0.07        3.16

...

The first, third and fifth numerical columns give the percentage of white-to-move positions that are, respecitively, draws, white wins or black wins. And the other columns give similar information for the black-to-move positions. I'd think it unlikely that a similar table for 6-man positions doesn't already exist out there in the ether somewhere, but I don't know where such is located.

EDIT: Sure enough, the second edition of Nunn's Secrets of Pawnless Endings (and not the first edition which predated available 6-man tablebases) does go at least partly toward what you're after. There is a summary table (pp. 325-329) that, while not providing the numerical detail of the table above, does include for each 6-man piece combination at least an indication of whether it is generally won or drawn (presumably based on whether a majority of positions are theoretically won or not, as above), along with information about the longest win and longest reciprocal zugzwang for each ending.

To use your example, Nunn notes that KRBKNN is generally a win for White, while the longest win is 223 moves from the following position:

[fen "1K6/5BR1/2n5/2n2k2/8/8/8/8 w - - 0 1"]

Some of the endings also get discussed in the text. For instance, Nunn gives an optimal line from the above position and attempts to give annotations that make the very complex play involved understandable. (Partial spoiler: 1.Kc8! is the only winning move at the start.)

This is end game theory... Usually this comparison is not done in middle game tactics or openings (obviously).

However, my best advice for you is to read about end game books, which completely cover scenarios of rook &bishop vs 2 Knights and MANY MANY other scenarios.

If you want a suggestion, read Domination in 2,545 end game studies. You won't be disappointed and you will find what you want, that I assure you.


Why did Puzzle Rush stop at the second fail? I was playing the popular Puzzle Rush game on chess.com (3-minute version), and the game stopped when I missed the second puzzle (I had 8 seconds left on the clock). The statement is "Three strikes and you are out!", and it usually complies.

I must clarify that this is not the updated version of Puzzle Rush, which started at 9 a.m. Pacific time on Thursday, November 21.

It's the second time I’ve seen this happen.
I am wondering if there is a special rule that I have missed, or if it is just a bug.

There is a 'quit' flag on the webpage of puzzle rush, so perhaps you could have accidentally clicked it.

The web version as implemented by chess.com is laggy and your clock runs down without you knowing when the browser is loading and the timer is suffering severe latency problems.
I created the original Prototype A of this puzzle app style and it was lag proof but chess.com copied it and didn’t know how to avoid this issue.


A deceptively simple eight piece endgame I am in the dark about the following endgame, with white to move. May someone with FinalGen (or a powerful engine) give me a response? Is it a White win or a draw?
[FEN "8/1k6/5R2/P7/1KP4p/5P2/8/5r2 w - - 0 1"]

No need for engine analysis, that's a win for White since that parciular a+c pawn endgame is won. White can simply trade the other two pawns with Rh6


What is a good chess engine to play against on an android phone? I have an android phone, and I have the Chess Free app. It is nice in that you can set the computer difficulty level and record games, and even play against another human, but it severely lacks analysis features. I've been having problems finding a good chess analysis program with analysis features on android. Does anyone have any good suggestions?

Droidfish app on Android is what you need. It has professional level GUI(with sophisticated analysis functions) with Stockfish engine pre-installed.

Do try 'Analyze This' App, especially for analyzing games with multiple Chess engines. Can even automatically Analyze games with English commentary!
https://play.google.com/store/apps/details?id=com.pereira.analysis

(Disclaimer: I am the developer! Happy to help!)


Non-Standard Knight Development From its starting square, a knight has 3 legal moves: The “standard” one (c3, f3, c6, f6), the “weird” one (a3, h3, a6, h6) and the “other” one (d2, e2, d7, e7).
In my games, I almost always do the standard move. And I completely overlook the other move by my opponent, to my detriment. When are the weird and other moves preferred?

It's probably first worth revisiting why the "standard" moves are normally preferred.
A white knight on c3 defends white's central square e4 and attacks black's central square d5. That is that knight attacks/defends/supports 2 out of the 4 central squares. In the opening those 4 squares are the most important squares on the board (unless you fall for a cheapo).
In contrast a knight on d2 only defends white's central e4 square. On d2 the knight is only half as effective as it is on c3. By symmetry the same arguments apply to knights on f3, c6 and f6.
In general in open games these four squares are the best ones for the knights on their first move. In closed positions it is not quite so clear cut. Often other factors make other squares better or just make those squares impossible.
In closed and semi-open openings these squares may not all be available and moving a knight there may not be possible. The Advance Caro Kann is probably the best example of this. After:
[fen ""]

1. e4 c6 2. d4 d5 3. e5

black can't put a knight on c6 because it is already occupied by a black pawn and f6 is also out of bounds because it is attacked by the white pawn on e5.
In the Winawer variation of the French Defence white puts a knight on c3 but this is a very committal move. Black can pin the knight with Bb4 and a double edged tactical battle is likely. Consequently at higher levels Nd2 is preferred heading into a Tarrasch variation of the French. This satisfies the key requirement of the position, defend the attacked white pawn on e4, while also avoiding the pin from the dark squared black bishop and allowing the d4 pawn to be defended with the move c3.
The other reason for moving a knight to d2/7 is to protect the other knight developed on f3/6 when it is pinned to the queen thereby allowing the queen to move without risking doubled pawns if black decides to exchange bishop for knight.
Finally moves like Nh6 use the h6 square as a staging post aiming for f7 or f5. These ideas come up regularly in the French Defence. Here are a couple of examples:
[fen ""]

1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 Bd7 6. a3 f6 7. Bd3 fxe5 (7...cxd4 8. cxd4 Nh6 {with the idea of Nf7 to put more pressure on e5 and if} 8. Bxh6 gxh6 9. Nh4?! Qb6 10. Bxh6 gxh6 11. Qh5+ Kd8) 8. dxe5 Nh6 9. O-O Nf7

If you play openings like the French or the Caro Kann as black then you will become more familiar with these ideas. In any case you should be mindful of possible advantages in playing Nd2/7 to protect a pinned knight on f3/6 making it easier to break the pin and possible advantages in leaving c3/6 free for a pawn to support a pawn on d4/5 or to kick a bishop on b4/5.

The "standard" movement of the knight in the opening is pretty much forced. Other than the Alekhine's knight movement (which is also inferior but not busted), other options of knight movement almost always give >1 advantage to the other side, busted and convertible by engines.


Can a rook win against a knight in the endgame? Suppose we have a rook and the opponent has a knight next to his king.

Is it possible to win this game theoretically?

E.g., in the following position (white to move), is it possible for white to win?

[FEN "8/8/8/3n4/3k4/8/K7/R7 w - - 0 1"]

In the specific position that you mention, the answer is a resounding no.  The king and the knight will defend each other, and white will not be able to force mate.

However, the knight is a clumsy piece.  If the knight is not positioned perfectly, then the rook will frequently be able to drive the knight to a bad square and deprive it of moves.  Eventually, the knight may be captured, or the king might be checkmated.

As an example of a position where the rook can win, take the following:

[FEN "8/1n6/8/8/2R2K2/8/5k2/8 w - - 0 1"]
[SetUp "1"]
[PlyCount "17"]

1. Rc2+ Ke1 2. Ke3 Kd1 (2... Kf1 3. Rf2+ Kg1 4. Rd2 Nc5 5. Kf3 Ne6 6. Kg3 Kf1
7. Rd5 Nc7 8. Re5 Na6 9. Kf3 Kg1 10. Rg5+ Kf1 11. Ra5) 3. Rb2 Nc5 4. Rb6 $22
Na4 5. Rb4 Nc3 (5... Nc5 6. Rd4+ Kc2 7. Rc4+) 6. Kd3 Na2 7. Rb1+ Nc1+ 8. Kc3
Ke2 9. Rxc1 *

Here, white can win starting with 1.Rc2+.  The plan is to drive the king to the first rank and then attack the knight while improving the position of the rook.

In your question, you mention specific cases where the king and the knight are close together.  In these cases, it is very important to know two key positions:

First, in this position, black can hold the draw:

No matter what white tries, the white king cannot approach the black king due to the knight.  Black will be able to squeeze out with ...Kb2.  Black's plan is to mark time by playing ...Na3 and ...Nb1.  White cannot make useful progress.

This position, almost the same, has one major difference - black can no longer mark time with the knight:

If white plays a waiting move, for example 1.Re2, then black must lose immediately.  Any move will lose the knight or allow mate in one.

If you're interested in a specific position, you can check out the Nalimov Tablebases online.  They have completely solved every position with 6 or fewer pieces on the board.

Out of curiosity I put Stockfish 2.3.1 to work on this and it did find a solution for white to win; however it took 60 more moves.  However just glancing at the results it would assume it could be done in less moves.

[FEN "8/8/8/3n4/3k4/8/K7/R7 w - - 0 1"]

1.Rd1+ Kc4 2.Kb2 Ne3 3.Rd8 Nd5 4.Kc2 Ne3+ 5.Kd2 Nd5 6.Kc2 Kd4 7.Rh8 Nc3 8.
Kd2 Ne4+ 9.Ke2 Nc3+ 10.Kd2 Nb1+ 11.Kd1 Na3 12.Kd2 Nb1+ 13.Ke2 Nc3+ 14.Kd2
Nb1+ 15.Kd1 Na3 16.Kd2 Nb1+ 17.Kc2 Na3+ 18.Kd1 Nb5 19.Kd2 Kc4 20.Rh4+ Kd5
21.Kd3 Nd6 22.Rh5+ Ke6 23.Ke3 Nf5+ 24.Kf4 Ne7 25.Ra5 Nd5+ 26.Ke4 Nf6+ 27.
Kd4 Ng4 28.Rc5 Nf6 29.Rc6+ Kf5 30.Rc5+ Kf4 31.Rc1 Kf5 32.Rc5+ Kf4 33.Rc2
Kf5 34.Rc5+ Kf4 35.Rc1 Kf5 36.Rc5+ Kf4 37.Rc1 Nh5 38.Kd3 Nf6 39.Ra1 Kf5
40.Rb1 Kg4 41.Ra1 Kf5 42.Re1 Nd5 43.Kd2 Nf4 44.Ra1 Ke4 45.Rb1 Nd5 46.Ra1
Nc7 47.Re1+ Kd4 48.Ra1 Nd5 49.Rb1 Nc3 50.Ra1 Nb1+ 51.Rxb1 Ke4 52.Kc3 Ke5
53.Re1+ Kf6 54.Kd3 Kf5 55.Kd4 Kf4 56.Rf1+ Kg5 57.Ke4 Kg6 58.Ke5 Kg7 59.Kf5
Kf7 60.Re1 Kg7 61.Re7+ Kf8 62.Kf6 Kg8 63.Re8+ Kh7 64.Ra8 Kh6 65.Rh8# *


What's the goal of a minority attack? I understand the definition of a minority pawn attack, is when one side has less pawns than other in a flank of the board (or any sector) and advances them to trade them with the oponent. The question is why would I want to do that? I imagine there is a different purpose of that for every game, but possibly there is a general reason that applies to various games. I heard here: https://youtu.be/ziCLlmz0ATo?t=4m26s that minority attack serve the purpose of leaving pawn weakness. Probably leave an isolated pawn?

The point of the minority attack, you have correctly pointed out, is to force pawn weaknesses. Usually, the weakness that you are going for is to create a backwards pawn. This weakness is very difficult to deal with for your opponent. Normal play is to gang up on the pawn, double your rooks along the file.

Weaknesses and to open lines against the remaining pawns.


Is there a site with preparation ideas for opening tabiyas? I deal with this problem every time. I have some 'default' repertoire and when preparing against concrete opponent, I find that it is highly probable we will reach some concrete well known position and I want be the one to come with system he can't expect me to play. Ok I can use book, engine, games to create interesting system myself, but it takes soooo much time. People already made thousands of preparations like this, coming with a sharp forcing idea hard to refute over the board, playing new move with completely different approach compared to main lines... Is there somewhere something like market of these ideas? Just pgn with 20 lines, for example. Or text. Anything that is good for titled players, computer checked lines, dangerous surprises for one game etc.

The SOS ("Secrets of Opening Surprises") books and articles (in New in Chess magazine) can be good references.  Once in the USATW I was paired up against a 2450 rated player.  I found references with a quick online search that he played the Caro-Khan.  I walked in the bookstore and looked in an SOS book and found a line Kasparov used in blitz a lot.  After 10 minutes of preparation I was armed  to get my well booked opponent out of his element and I won my best game of the tournament.
I've done such things with the Chess Informants a lot including preparation against Yermolinsky in the US Open.  I would say Chess Informant is best if you have the time and money.

i don't know you want a opening repertoire for positional or attacking one. I use to play mainly positional repertoire but for some blitz chooses attacking one. I followed some lectures of yassar serwain's from saint luis club , it is available in youtube . I also follow a pdf of gufeld's repertoire Repertoire of Gufeld and another man

And also following some advice from GM Arthur Yusupov . But at last I must say that if you do not rely on your repertoire then you cannot become a good player , and if you do not make a hard work on your openings then you cannot make a solid typical opening (most of the player don't like this type of opening which has been analysed , like with 48 moves or more!! ) like Lev poluguasky (Pronouncing wrong?!) , His openings homework was great , every player was scared to play with him , he is mainly known for his hardwork on openings (his favorite opening was sicilian najdorf , and he invented the opening Sicilian Najdorf Poluguasky variation , which is sharp like axe ) , if you make a hardwork on your opening you can be one like him . And at one stage he said by this hard work attitude  he can prepare any master player into world champion.


How do I stop blundering my queen? I have a particular bad habit when I play chess. I play reasonably well (at least by the standards of people I play with), and am quite careful with my pieces. But in about 80% of games I play, once I get into a good position - one or two pieces ahead and in control of most of the board - I nearly always move my queen to attack something and then lose her. This is usually due to an unappreciated threat (sometimes I've even seen the threat a turn or two before).

Is this a recognised problem for many players, or is it just me? If it is recognised, are there any recommended strategies to overcome it?

It's certainly not just you. While you describe a particular blind spot involving your queen, the more general phenomenon of throwing away sizable advantages is a very common one in chess, and it can be tough to kick. Here's a well-known saying that seems to be due to longtime U.S. champion Frank Marshall (and I'm paraphrasing):

  The hardest thing in chess is to win a won game.

I've read folks like Vladimir Kramnik echo this very point as well (as have thousands of others, I'm sure). So this kind of thing is something that affects the very best out there, not just you. There can be many reasons behind this kind of difficulty (e.g. stubborn, defiant resistance from the player on the losing end), but the primary factor that the winning player can remedy himself is simply to avoid "relaxing" too soon. After all, as your experiences show, even a huge material advantage can disappear if you let your guard down even a little bit and blunder away a queen.

Something I noticed long ago in my own games is that if I allow myself during the game even just to briefly imagine a future in which I've already won (e.g. hypothetical thoughts of who I'll be playing in the next round of a tournament once I've won), then things often become much harder the rest of the way, even if I immediately catch myself after the fact and refocus on the game. Is that real, or all in my head? It doesn't matter, because if it's in my head that's enough to affect my chess play.

Refusal to consider any game won until it's actually over, coupled with constant tactical vigilance, will go a long way to avoiding the pitfall you've described. Exactly how to arrange for that in your own head will vary from person to person, of course, but that general approach is important. Basically, what I'm saying here goes hand in hand with the nice point Wes makes in his answer (slow down, take a breather before moving); take every move in the game just as seriously as any other, whether it's the first move of the game, or you're up three pieces, because the cruel truth of chess is that an entire game's worth of brilliant moves can be ruined with a single bad one.

I blunder lots as well. So I exchange queens at every opportunity so that I cannot blunder it.


Mate Prevails - Chess Rule Is "Mate Prevails" not an FIDE rule? I couldn't see it in the FIDE website but I heard about it from many players.

UPDATE:
"Mate Prevails" is a claim some players make that they win the game after 'flag fall' if they can force a checkmate in one move.

If you make a checkmating move before your flag falls, but then your flag falls before you press the clock, you win. The relevant FIDE rules (emphasis mine) are:

5.1.a. The game is won by the player who has checkmated his opponent’s king. This immediately ends the game, provided that the move producing the checkmate position was in accordance with Article 3 and Articles 4.2 – 4.7.
6.2.a. During the game each player, having made his move on the chessboard, shall stop his own clock and start his opponent’s clock (that is to say, he shall press his clock). This “completes” the move. A move is also completed if the move ends the game (see Articles 5.1.a, 5.2.a, 5.2.b, 5.2.c, 9.6a, 9.6b and 9.7).
6.3.a. When using a chessclock, each player must complete a minimum number of moves or all moves in an allotted period of time.
6.9 Except where one of Articles 5.1.a, 5.1.b, 5.2.a, 5.2.b, 5.2.c applies, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player.

It's not a real rule in FIDE rules. Seems like an anachronism.


Is it really possible to beat a stockfish level 8 computer in any time that is between 3+0 and 15+0? I've watched a couple of games where people play against stockfish level 8 on lichess, and they pretty much lose all the time. Is it possible for someone to beat a level 8 computer in any time between 3+0 and 15+0?

IMHO playing against Stockfish level eight is a lost cause when playing against its full 16 quad core processors and basically unlimited flash storage, no matter the time constraints. Magnus Carlson stated a couple of years ago that he always lost against that computer program. The lichess version is but a shadow of its real self.

This book lists blitz/rapid games won by a human against Stockfish:

https://www.amazon.com/Human-Versus-Machine-Stockfish-Komodo-ebook/dp/B0768G8R2C/

  My winning games against Stockfish and Komodo. This is for real. I
  have played over 50 thousand engine games, of which more than 10
  thousand against Stockfish, and a large number against Komodo, so I
  have my fair share of wins. Read the book to learn what openings are
  suitable to handle the machines, how to impose your style of play, and
  how to approach the game in a tactically relevant way. The games are
  amply commented and diagrammed. You thought competition between humans
  and machines has already ended? Not at all, it has just started!


What can I learn from my "80 average centipawn loss" game, which I thought I played well? In a LiChess game (Vakeesh vs. becky82), during the game I thought I played well, and won as black without and real complications.  Here's the game:

[fen ""]
[Event "Rated Classical game"]
[Date "2019.01.23"]
[White "Vakeesh"]
[Black "becky82"]
[Result "0-1"]
[UTCDate "2019.01.23"]

1. e4 c6 2. d4 d5 3. e5 Bf5 4. f4 e6 5. Be2 c5 6. c3 Nc6 7. Be3 Qb6 8. b3 cxd4 9. cxd4 Bb4+ 10. Nd2 Nxd4 11. Bxd4 Qxd4 12. Nf3 Bxd2+ 13. Nxd2 Ne7 14. Bb5+ Nc6 15. Rc1 O-O 16. Bxc6 bxc6 17. Rxc6 Qxf4 18. Qe2 Rfc8 19. g3 Qd4 20. Rxc8+ Rxc8 21. Kf1 Bd3 22. Qxd3 0-1

However, the post-game computer analysis gives me a "80 average centipawn loss", which implies that for my average move I blundered the equivalent of 4/5-ths of a pawn.  (My opponent had "123 average centipawn loss", outblundering me.)  I'm not sure what to think of this.

Question: What can I learn from my "80 average centipawn loss" game, which I thought I played well?

It seems I repeatedly played "a good move" rather than "the best move" (as there were often multiple winning moves).

Edit: I'm after humanly understandable "take home" lessons from the game, which I can apply to other games in general (when using an engine is considered cheating).  I'm also after an evaluation of the applicability of the engine analysis (available from the linked game) to a human player trying to improve.

I'm not seeking "this move is better because the computer says so", I'm seeking how I can find the best moves as a human in a tournament game.

You are asking two very different question: How to interpret the number 80, and how to make that number go down :-) I'll focus on the first one.

80 means that on average, you overlooked many better moves. What this says about your playing strength depends on how hard those better moves were to discover. In complicated tactical positions higher values are normal. You may miss many opportunities that the computer can see because it looks, say, 10 moves ahead. So the bar is high.

In calm positions the centipawn loss is lower because there are no tactics (as by the definition of "calm"), so as long as you don't blunder your move cannot be a lot worse than the computer's optimal move.

I've had games with a centipawn loss below 20 and above 100 even though, I'd argue, my playing strength was the same. (My) Chess960 games tend to get into complicated tactical positions quickly, for example, so my centipawn loss in those is higher.

Finally, it's an arithmetic mean so it is susceptible to outliers. Many good moves and one blunder will give the same result as just mediocre moves.

You are probably aware that Lichess offers a tool to evaluate your games based on centipawn loss ("Chess Insights", on your profile page).

Honestly, do a computer analysis and look at what the computer says are mistake and blunders.

Now figure out why the computer called them that. Look carefully at the position and the analysis. If you have a (specific) position that bugs you, ask here.

Another alternative is to get a chess coach.


If there is a winning strategy, is it for White? We do not know, given two perfect players White and Black, whether the game would necessarily end in a draw, or necessarily end in a win (for either Black or White).

However, can we prove that if there is a winning strategy, then it is for White? In other words, can we prove that Black must either lose or draw?

If there is such a proof, no one has found it, and I doubt very much that such a proof exists (it is hard to imagine a mathematically provable "guaranteed-draw" strategy as White). One would certainly expect White to have an advantage if anybody did, but there are some downsides to going first as well (you have to disclose information before your opponent), so it is theoretically possible that the downsides outweigh the upsides. That said, the probability of that being the case seems to be infinitesimal.

White would have the advantage of opening the game, but I would doubt there is ever a winning strategy as you suggested.


Can the book 'Grand master Preparation: Calulation' by Aagard be useful for a Class B chess players? I heard in most chess forums this book is for 2400+. Can this book also be useful for Class B players? I'm looking for a book to improve my calculation and planning. If so, in what ways? What would be the best way to self-study this book as a Class B?

I'm rated around 2150 Elo and I used the book two years ago, to solve exercises on the way to work. I could solve approximately 50%, which felt somewhat disheartening, though objectively, I guess, it's pretty ok for my level. I definitely profited from the training.

I wouldn't recommend the book for players significantly weaker than me. Mostly because it's demotivating if you are always struggling to even think in the right direction. I have found that the final instalment of the Yusupov series fits my own level better (i.e. tough but solvable).

But if you can keep your motivation up, even without much positive feedback, of course you can profit from thinking deeply about just about any position.

I've read 60 Memorable Games by Fischer, Art of Attack by Vukovic, Understanding Chess: Move by Move by Nunn, and My System by Nimzowitsch.

These books got me to ~1800, but something was missing.

Before the end of 2018, in December, IM Alejandro Moreno recommended Chess Praxis.

"Another book?" I thought. Weary and withered, I reluctantly read the book. I really felt like a law student at this point (mind you, I was studying chess in a quiet area of the law library - with the rollable board and wooden pieces).

I've read Chess Praxis. Here's where it's gotten me:

(Note the highest rating in October - that was when I finished reading the three books listed at the beginning of this post, minus Nimzowitsch. I was playing sharp, but my positional play was unsound. So once I got bored of the lines, I dropped down to ~1700 (!) in a week).

And in my last USCF Tournament (2/16/19), I scored 2.5/4.0 in the open, beat an expert, drew a National Master, and took a 1900 to the cleaners. My rating exploded from 1815 -> 1880.

If there's one book you must read, it's Chess Praxis.

Reading those five books only took three months, but those will be the three most critical months of your life.


Has anyone attempted to characterize chess mathematically? From years of being student, researcher, and practitioner of chess, I feel like it possesses completeness and elegance that are found in mathematical proofs and theories. Thus, it seems only natural to imagine that it should be possible to describe chess in mathematical terms. By that I mean an elegant description, like a compact set of formulas or a proof that chess belongs to such and such field of mathematics. Intuitively, it feels like it should be able to fit in group theory. Does anyone know what attempts have been made in this regard? I would like to specifically exclude engines, neural networks, and the like from the discussion because, despite the obvious success in increasing the quality of play, those attempts do not constitute theoretical proof.

There are many different aspects of chess which can be formalized mathematically. Since the 19th century at least, chess has been mined as a resource to drive mathematical innovation. So when talking about a mathematical characterization of chess, it's not a single modeling that we are talking about, which grabs every feature, but rather a number of models, in which the power of each is paradoxically in the letting go of some aspect of chess which is not relevant for that analysis.

Perhaps the earliest success (not counting the counting :-) of grains of rice on a chessboard) was Zermelo's Theorem (yes by one of the founders of ZF Set Theory) which states that in chess "either White can force a win, or Black can force a win, or both sides can force at least a draw".

Combinatorial Game Theory (developed by celebrated mathematicians John H. Conway, Elwyn Berlekamp and Richard Guy) has been successfully applied to chess. A couple of assumptions in this theory go against its general applicability to chess though. One is that a win in CGT is solely if your opponent can’t move which does not address stalemate. Secondly there is the notion of “entailing move” (e.g. check) where if one person plays, the other player must respond rather than the first player playing again. But Noam Elkies has derived some non-trivial results in chess endgames by computing their CGT value - references given in his chess page http://www.math.harvard.edu/~elkies/chess.html: "On Numbers and Endgames" and "Higher Nimbers [sic] in Pawn Endgames on Large Chessboards".

You mentioned group theory - well curiously the set of combinatorial games under composition does form an abelian group! To be fair, the two obstacles mentioned above do prevent chess itself from behaving in this way.

There is a massive amount of combinatorial work which has been done around the chessboard. Vaclav Kotesovec has published online an 800 page book just on the subject of non-attacking chess pieces (generalizing the 8 queens problem massively). See http://www.kotesovec.cz/ for the link. This is related to Magic Squares, Experimental Design, etc.

There is also, starting in Finland with Eero Bonsdorff, a long lineage in path enumeration chess problems, counting the number of ways that a position can be reached. This often involves the analysis of Standard Young Tableaux, which also underpin representation theory of symmetric groups. Fibonacci numbers, Catalan numbers and Euler numbers are all frequently found here, together with other combinatorial identities whose realization can be found lurking in ingenious chess compositions. See https://pdb.dieschwalbe.de/search.jsp, and type g='mathematics' in the search box.

The knight's tour problem is also famous for helping to push the study of Hamiltonian graphs, and particularly the challenge of counting the number of such objects. See https://www.mayhematics.com/t/t.htm.

The theory of computation also asks about whether chess is determinate. This is all about arranging sets of pieces in much bigger boards to try to make machines that are equivalent to Turing machines. This brings us to the subject of the limits of computation, which is where I would make the point that if a mathematical theory characterized chess completely, then we should be no more able to reason with it than we are to play at chess itself. That might allow us to escape some of the linguistic challenges of the current laws (e.g. whether pawns can be oriented).

I think there is also research value in a mathematical description of how chess conventions apply consistently to chess problems including fairy chess. Guus Rol has a very ambitious  program which reduces each turn to “micro-phases” and claims to be able to determine with great accuracy how fairy conditions interact in complex “retro-active” situations, where both retro and forward logic is necessary. I don’t know if he will ever complete his theory.

I personally would like to see a more modest theory, which treats each move as atomic and although it doesn’t cover fairy chess so well, at least can cover retro-active aspects of problem conventions such as castling and e.p. Even that has not been done yet.

The mathematical physicist Roger Penrose published a chess position about 2 years ago which was intended to argue his long-held position that there is a fundamentally different kind of reasoning displayed by humans than an AI grounded in "computable functions" can demonstrate. See https://en.chessbase.com/post/a-chess-problem-holds-the-key-to-human-consciousness

Even though the theory of random graphs, and Monte Carlo analysis has been applied very successfully to engines, particularly the most recent generation, I don't think this disqualifies it from being considered a mathematical theory.

There is also a linear algebra approach to counting moves and positions. “If chess is a graph, what is its maximum eigenvalue?” is a very real and interesting question. See Francois Labelle's site at http://wismuth.com/chess/statistics-games.html

Linear algebra can be applied successfully to other chess related questions e.g. how many ways are there for a rook to move from a1 to h8 in exactly n moves? How about a king?

For many years, Noam Elkies & Richard Stanley have been collaborating on a book on chess and mathematics. I don't know when it will finally emerge, or whether they have given up on this. But "The Mathematical Knight" given on Noam's chess page linked earlier perhaps gives a foretaste of that book. Richard Stanley is one of the leading lights in Combinatorics: see http://www-math.mit.edu/~rstan/chess/queue.pdf, and Noam's birthday article https://arxiv.org/pdf/math/0508645.pdf

There is also already a book "Mathematics and Chess" by Miodrag S. Petkovic, but I am not familiar with its contents.

Some of these ideas are listed in a Wikipedia page: https://en.wikipedia.org/wiki/Category:Mathematical_chess_problems, and there's a more specific page https://en.wikipedia.org/wiki/Mathematical_chess_problem.

If anyone else has other examples of chess and mathematics, please mention them in comments and I will try to incorporate them in this response. If anyone has links that illustrate the topics I am mentioning, please add them, thanks.

Finally: math.stackexchange.com has 62 pages of chess entries!?!

Chess isn't the sort of object that mathematicians are interested in studying. Mathematicians care about problems that are in some way infinite: either infinite objects or finite objects of which there are infinitely many examples. Chess is completely finite. There is only one chess, it uses a finite board, there are finitely many possible positions. If chess is played rationally (and we can't hope to characterize it without that assumption) then games are finite in length. "Rational" basically means that either player will claim a draw as soon as they have the right to, and that means that games are less than about 5900 moves, which means there are only finitely many games.  A mathematician might study the prime numbers, but they're not going to study the single number 1827368429.

To a mathematician, "solve chess" is just a calculation, and mathematicians aren't interested in calculations. The fact that it's a culturally important calculation might encourage somebody to try, but it's hard to see anybody having the time to do something so complicated. It's the sort of thing that would take decades of full-time work and, if you failed, you'd have basically nothing.