Chess puzzle that is hard to understand Today I was solving a chess problem as following picture :

[fen "r1bqr1k1/1p3nbp/2pp2p1/2n2P2/p1PN1P2/2N1B1PP/PPQ3B1/R3R1K1 b - - 0 1"]

The solution given was 1...Rxe3, but I did not get the actual benefit of this solution. Can anyone explain this?

The point is that after 1...Rxe3 Black will be winning material, as the sole defender of the white knight has been removed, and a pin tactic is coming. Specifically, after 2.Rxe3 (anything other than this recapture means Black has just won a piece for nothing) and 2...Bxd4, White has no way to stop the follow-up 3...Bxe3+ since the rook is pinned to the king, and so Black has netted an extra piece anyway.

[FEN "r1bqr1k1/1p3nbp/2pp2p1/2n2P2/p1PN1P2/2N1B1PP/PPQ3B1/R3R1K1 b - - 0 1"]

1...Rxe3 2.Rxe3 Bxd4 *


What are some chess books on openings which include computer analysis? I once had a book on the sharp Wilkes-Barre variation of the Two Knights Defense written in the 1970s in which there were a few moves which were said to be clearly winning for one side in which a computer analysis of the position said otherwise. The situations were unusual, for example the last position in the analysis would have three threats in it and the conclusion would be that one side is clearly winning. Then the computer would find a move responding to all three threats and say that the other side has the advantage.

So my question is 'What are some books on chess openings that show how a computer rates the top move choices after analyzing each for a certain amount of time?'

If I recall correctly, The Wilkes-Barre is Traxler (correct me).

I once analyzed it quite deeply, and the only way white can hope for a win after 5. Nxf7 is 5...Bxf2+ 6. Kxf2 (6.Kf1 is also a tricky draw.) Nxe4+ 7. Ke3.

Or he can simply play 5. Bxf7+ and be a healthy pawn up.

You can do this analysis yourself.


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

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

Short answer: No such thing

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

Other techniques that can influence the engine:

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

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

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

It's hard to to tell the engine:

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


Is there a name for this common type of blunder? I'm sure most of us have done it at least once ... I had a position where one of my pieces were under direct threat - I was a pawn up, but my opponent attacked my rook with his bishop and threatened to get the pawn back if I was careless. I tried to calculate every possible continuation and got lost in the possibilities ... and before I knew it, I was totally absorbed by the position 4 or 5 moves ahead and completely forgot that my rook was hanging. Keeping a mental eye on the future position instead of the position in front of me, I made a silly move (moved my knight, if I recall) and lost my rook.

Naturally, and quite embarrassingly, my teammates all wanted to know what happened since it looked so good for me at one point. Instead of trying to explain the intricacies of the position, it would be convenient if I could tell my club mates that I lost because of an "X-blunder". Does this type of blunder have a name?

It is probably a bit more general than what you describe, but one move blunders are often called (a case of) "chess blindness".

I'm not a hundred percent sure, what exactly happened in you're case but often people make the second move of a combination (or variation) first, because they are ahead of the actual position. But I don't know a succinct term for that.

If you listen to top players post game interviews, what you hear incredibly often is "I just forgot about move xy". I guess if that description is good enough for Aronian and Co, it is good enough for us. ;-)

Another loosely connected term is "residual image". This describes the case when you are calculating and pieces that already moved, are still on their original square in your mind.


What are the most common squares to be overworked? Generally are there any distinguishable patterns you look find in the opening that you recognize as weak, or exploitable. Or generally any openings that provide the over-bearing sense of duty on a piece?

Prior to castling, f2/f7 are the most exploitable squares in the game, because they are defended by only one piece: the king. That's why so many king-stuck-in-the-center games are rounded off by a piece sacrificing itself on those squares.

On the queenside, the c2 and c7 squares also have problems, because of a tactical sequence like this:

1. Bf1-b5+ Qb6xb5
2. Nd5-c7 (forking the queen with either a king on e8, or a rook on a8)

But these tactics happen less often than tactics on f2-f7, because the queen is usually a better defender than the king.


An unnecessary threat? I found myself in a game with this position. Last Black's move was a Queenside castle, which let him a little bit uncovered. My first spontaneous move idea (which I finally played, because of time trouble and having no really other interesting idea) was to play Rc1, to put pressure on the king on the C column added to the fact that my bishop on f4 makes the move Kb8 impossible (and then c4 etc).

However, this can be easily countered just by playing Bd6.

So, we all know the importance of a threat (which is, like Nimzowistch said, stronger than the execution), but do you think it's a good move in this position ? or, knowing that it can be countered, do I had to choose another "more effective" move ? (like I don't know : a4 ?)

Would you have played Rc1 ? If not, what would have been the best move ?

Stockfish thinks 1. Rc1 leads to a even game or maybe a draw. It's undone immediately by 1. ... Ba3.

Stockfish preferred 1. Nh4 with a 60 centi-pawn advantage to White.

[FEN "2kr1b1r/pp3p1p/1q2pp2/3p1b2/3P1B2/1PP2N2/P4PPP/R2QR1K1 w - - 0 1"]

1.Nh4 Bg6 2.Qf3 Be4 3.Qh5 Rd7 4.Rad1 Rg8 5.c4 Bb4 6.Re3 Qc6 7.Qe2 Bd6 8.Bxd6 Qxd6 9.f3 Bg6 10.c5 Qf4 11.Nxg6 hxg6 12.b4 Qc7 13.b5 Kb8 14.Rb3 b6 15.Qe3 g5 16.Rc1 Qf4

The 1. c4 move fares ok at about 40 centi-pawns but by the end any winning chances look like an illusion.

[FEN "2kr1b1r/pp3p1p/1q2pp2/3p1b2/3P1B2/1PP2N2/P4PPP/R2QR1K1 w - - 0 1"]

1.c4 dxc4 2.Rc1 Bd6 3.Bxd6 Qxd6 4.bxc4 Rhg8 5.d5 Qf4 6.g3 h5 7.Nd4 h4 8.Nxf5 Qxf5 9.Rc3 exd5 10.cxd5+ Kb8 11.d6 Qd7 12.Rc7 Qxd6 13.Qxd6 Rxd6 14.Rxf7 a6 15.Ree7 b5 16.Kg2 hxg3 17.hxg3 Rgd8 18.Kf3 Rd3+ 19.Kf4 Rd2 20.Rb7+ Ka8 21.Ra7+ Kb8 22.Rxa6 Rxf2+ 23.Ke3 Rg2 24.Rb6+ Kc8 25.Rxb5 Rxa2  (964.21)


How do generic game engines work? The evaluation functions for chess usually includes chess specific knowledge. However, Zillions of Games is able to play any game based only on a description of how the pieces move and winning/losing/draw conditions. And as I see, does quite a good job.

Engines like Fairy-Max can only play chess-like games, which includes many assumptions in its design that do not need to be generalised. But when making a generic game engine (which I dream of doing), the engine simply can't assume almost anything.

I got a nudge in the right direction with the post 'ab-initio' piece values on TalkChess. Yet it does not provide the whole picture.

So, how do generic game engines (like Axiom Development Kit, which is an independent engine that plugs into Zillions; or even the very Fairy-Max) evaluate position?

Edit 1: I found some more information in the 1993 paper by Barney Pell entitled A Strategic Metagame Player for General Chess-Like Games (found it from the "General Game Playing" page on chessprogramming.org).

I don't know about Zillions specifically, but it's a reasonably good strategy in most games to maximise your own flexibility of action while minimising your opponent's.  This is certainly true for chess; there are competent chess engines (ie. strong enough to beat an amateur consistently) which use only material value and mobility for evaluation.

The Beale Effect (ie. minimax with random position evaluations) yields a reasonably good chess engine with a modest depth of search, plateauing around 2000 ELO.  This relies entirely on a second-order effect of mobility, ie. you're most likely to find the highest random value in a part of the game tree that branches a lot.

I would not be surprised, therefore, to find that Zillions uses either a random evaluation or one based on mobility.  The value of a piece, after all, is strongly correlated with its mobility.


Why isn't this threefold repetition, forcing a draw? Here's my scenario, White has pawns on c2 and a2, and a king on c1, while Black has a queen on b4 and a king on d1.

[FEN "4k3/8/8/8/1q6/8/P1P5/2K5 b - - 0 1 "]

1...Qe1+ 2.Kb2 Qb4+ 3.Ka1 Qe1+ 4.Kb2 Qb4+.

Why isn't this threefold repetition? I'm the player with Black, we've been going back and forth for 30 moves. I've offered a draw and the guy won't accept. I have the weaker position on the board, which is why I want a draw. Is this just bad chess ethics on my part?

There is no such thing as "3 move repetition". To claim a draw, the position must be repeated three times (although it does not have to be in a row). In your example, the position with a Black queen and b4 and a White king on b2 has only occurred twice so far. You can claim a draw by repetition of position the next time that you can cause that position to appear.

If you make such a valid claim and your opponent refuses to honor it, he or she is not playing by the rules of chess. If you are playing on some computer service that does not recognize a valid claim of threefold repetition, the service does not implement the full rules of chess.


How do engines read PGN? I'm writing a small chess engine in LISP. I was trying to read some PGN file, at first it seemed like a piece of cake. But then I realized something.

Most of the PGN files, don't tell which is white and which is black. I mean if white plays e4 an later d5, how does the engine knows if he has to take or not? I could name the black pieces bN for example but by doing so i won't be able to import PGN easily.

Should i increment by 2? is that how PGN parsers do it?  Say the first three moves in a match are e4 e6 f4, should i create a recursive function to read x + 2? to skip whites move?

There is a detailed standard of PGN available, for instance here: PGN standard at the Wayback Machine.

You will never see "e4 e6 f4" in a PGN file, since it is mandatory to mention the move number before white's move: "1.e4 e6 2.f4".


Harry Potter Chess Analysis So, I've been reading Harry Potter and The Philosopher's Stone. If you haven't read the book yet, or watched the movie, and you don't want any spoilers, stop reading this question. Continuing, there is this chess scene, where Harry, Ron, and Hermione had to play their way through a giant board. They were black. Harry became a bishop, Ron a knight, and Hermione a "castle" which I guess refers to the rook. Is there such game where it followed the conditions that the book said?
These conditions are:

White starts with 1. e4

The white queen takes both black knights

The second black knight (Ron) sacrificed himself to the white queen in order for a bishop (Harry) to travel 3 spaces to the left for mate

The first black knight was taken for a trade for a black rook (Hermione) to take a white bishop

Both the bishop and rook (Harry and Hermione) were in danger twice

The second black knight (Ron) took the most white pieces

The same black bishop (Harry) went 4 spaces to the right in the opening

well my 2 comments got upvoted, so who knows, maybe i can turn this into an answer.
(Note: I wasn't really into chess or chess960 at the time I read the book (except that I played a few tournaments as a kid), so wow this was a little nostalgic. When I did get more into chess/chess960, I read about the silman position. That's about it.)
jeremy silman talked about the position in these 2 links in the description here. unfortunately, they're both dead. let's see if i can dig up web archive. oh yeah here we go
https://www.jeremysilman.com/book-review/creating-the-harry-pottter-chess-position/
(also http://web.archive.org/web/20170801000000*/jeremysilman.com/shop/pc/Creating-the-Harry-Potter-Chess-Position-87p3692.htm and http://web.archive.org/web/20111201000000*/jeremysilman.com/movies_tv_js/harry_potter.html)

aaaand of course there's agadmator: Ron Weasley Sacrifices Himself for the Team

anyway, let's see if the game in the movie satisfies the conditions

White starts with 1. e4

Yes. Ron does Scandinavian defense.

The white queen takes both black knights

Well, no, just Ron. But the other knight doesn't really do anything, so I don't see why there couldn't have been a position where Harry, Ron and Hermione have lost their other knight.

Wait, maybe, there was AN EARLY UNDERPROMOTION.

The second black knight (Ron) sacrificed himself to the white queen in order for a bishop (Harry) to travel 3 spaces to the left for mate

Yes, assuming you don't count the intermediate move of capturing the queen (the movie didn't seem to count this!)

The first black knight was taken for a trade for a black rook (Hermione) to take a white bishop

see (2). Also, Hermione doesn't seem to have moved much. But she does have control of the f-file.

Both the bishop and rook (Harry and Hermione) were in danger twice

Harry: Yes. Immediately before Ron checks king at end, Harry, as the dark square black bishop, is in line of sight of white queen.

Hermione: Seems possible. There's no indication for Hermione in danger, but I don't see why there can't be a game like this.

The second black knight (Ron) took the most white pieces

When playing a game, I don't know of anything where people keep track of which piece captured the most pieces. This sounds something like determining which piece is like the 'MVP', like the online pokemon TCG or csgo. I don't think this is a chess thing. But I guess it seems plausible.

The same black bishop (Harry) went 4 spaces to the right in the opening

Harry as the dark square black bishop could've done Bb4, like in Nimzo-Indian Defence, but Nimzo-Indian Defence is a response to 1.d4 and not 1.e4. Perhaps there's some variation of Scandinavian that involves Bb4. According to this, there's something called 'Scandinavian, Anderssen counter-attack orthodox attack' that goes

e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. d4 e5 5. dxe5 Bb4 6. Bd2 Nc6 7. Nf3

[White "Some 1.e4 player"]
[Black "Some Scandinavian player"]
[Result ""]
[FEN ""]

1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. d4 e5 5. dxe5 Bb4 6. Bd2 Nc6 7. Nf3

Also, notice that before capturing the queen, Harry is along the same diagonal of b4 and Harry's starting square (f8).

But actually 4 spaces to the right is a pretty common thing I think like Ruy Lopez.

Update: Does Magnus Carlsen Remember the Position in Harry Potter Movie?
Here, Carlsen claims that the moves Qc3 and Nc6 were played. Not sure either of those moves were played, but in the silman position Qxd3 (not Qd3 and not Qc3) and Nh3 (not Nh6) were played.


What is the largest amount of players at once that can play during a single chess game? I understand there is 3 man and 4 man chess but is there anything higher?

I've played 3- and 4-board "bughouse" with 6 or 8 people total, and can imagine higher counts though the logistics must soon become unmanageable.

In another direction, you can have a consultation game on a single board.  Such games used to be 2-on-1 (handicap) or 2-on-2 affairs, but in the Internet age the number of players on a side is virtually unlimited, as was already seen in this famous game back in 1999.


What software can I use to self-assess my own Elo rating? What software (preferably free) can I use to do a self assessment to determine my own Elo rating?


Why not 7.Qa4+ in Carlsen vs Navara QGD In the game of Carlsen vs Navara Biel Chess 2018, on move 7 why did Carlsen play e3 instead of playing Qa4+ and taking that hanging bishop?

I guess you mean the game below and at the 7th-move: 7.Qa4+ doesn't win the bishop because black can reply with Nc6 blocking the check and defending the bishop.

 [title "Biel, Carlsen vs Navara 2018"]
 [fen ""]
 [startply "12"]

 1.d4 Nf6 2.Nf3 d5 3.c4 e6 4.Bg5 Bb4+ 5.Nc3 h6 6.Bxf6 Qxf6 7.e3 (7.Qa4+ Nc6) O-O 8.Rc1 dxc4 9.Bxc4 c5 10.dxc5 Nd7 11.O-O Nxc5 12.Nb5 a6 13.Nbd4 b5 14.Be2 e5 15.Nc2 Rd8 16.Nxb4 Rxd1 17.Rfxd1 a5 18.Nd5 Qd6 19.Nxe5 Bb7 20.Bf3 Rc8 21.Ng4 Qf8 22.h4 Nd7 23.Rxc8 Bxc8 24.a3 h5 25.Nh2 g6 26.Be2 Ne5 27.Bxb5 Bb7 28.Nc3 Qe7 29.Rd4 Qe6 30.Nf1 Qb3 31.Rd2 Nc4 32.Rd7 Nxb2 33.Rxb7 Qxc3 34.Be8 Kf8 35.Bxf7 Qc6 36.Rxb2 Kxf7 37.Rd2 Qa4 38.Rd3 Qxh4 39.Rd7+ Kg8 40.Rd4 Qe7 41.a4 Qa3 42.g3 Qa1 43.Kg2 g5 44.Nd2 g4 45.Ne4 Qc1 46.Nf6+ Kf7 47.Nxh5 Qc6+ 48.Kg1 Qc1+ 49.Kh2 Kg6 50.Nf4+ Kf6 51.Ng2 Kg5 52.Rf4 Qd1 53.Nh4 Qc2 54.Nf5 Qd3 55.e4 Qd7 56.e5 Qh7+ 57.Kg1 Qg6 58.Nd6 Qe6 59.Rf5+ Qxf5 60.Nxf5 Kxf5 61.f4 gxf3 62.Kf2 Kxe5 63.Kxf3 Kf5 64.Ke3 1-0

In case white tries to further pressurise the knight on c6 after 7.Qa4+ Nc6, with e.g. 8.Ne5 black always has the option of taking on c3 first with check and then reacting to Ne5 with Bd7.


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

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

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

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

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

Deutsche Schachzeitung 1906 (vol. 61)
permalink: https://hdl.handle.net/2027/njp.32101072325978
pages 129, 161. 193, 257
Deutsche Schachzeitung 1907 (vol. 62)
permalink: https://hdl.handle.net/2027/njp.32101072325960
pages 1, 97, 161, 225
Deutsche Schachzeitung 1908 (vol. 63)
permalink: https://hdl.handle.net/2027/uc1.a0002788768
pages 1, 101, 197, 293
Deutsche Schachzeitung 1909 (vol. 64)
permalink: https://hdl.handle.net/2027/njp.32101072325945
pages 33, 97, 161, 225, 321
Deutsche Schachzeitung 1910 (vol. 65)
permalink: https://hdl.handle.net/2027/njp.32101072325937
pages 65, 129


Do chess engines store all of the previously analysed positions between moves I am starting to play with chess engines. I notice that the best chess engines can take several minutes to move. I am wondering why. Before each move the engine examines all legal future moves to some depth. However it then seems to repeat this exercise for the next move. Given that the previous move was already included in the tree of moves examined, is this not inefficient ? Or have I misunderstood ?

[Edit: I am assuming that the reason why move analyses are not cached is due to some memory limitations of the computer that just make it faster to restart the analysis]

Programming chess engines is very complicated territory, so right up front I'll point you to the Chess Programming Wiki, which has a lot of great information on this topic.

Background

Chess calculations (and many similar things) are generally modeled and thought of as "game trees" or "decision trees". Broadly, this tree is a directed graph, with one node at the top (the current position), leading to a node for each possible move, each of which leads to more nodes for each possible next move, and so on.

In their most simplistic, brute-force form, Chess engines generate all positions on this tree down to some depth limit ("ply"), evaluating each resulting position based on some complex criteria1. Then it plays the move that seems to lead to the best result. Nowadays, a lot of really complicated techniques have been developed to limit the number of positions that the engine has to look at, but I'm going to ignore those for the purpose of this answer, because they don't change the real issue at hand.

Math Tangent

The basic reason that engines typically take about the same amount of time to consider each move is that the size of the decision tree increases exponentially with depth (k).

Consider the starting position. The top of the tree (k=0) is one node. There are twenty possible first moves for White, so there are twenty nodes at depth k=1. Then, Black also has twenty available moves for each of White's options: so at k=2, there are 20 * 20 = 400 possible positions! And it only gets worse as the players develop their pieces!

For example, let's pretend that there are always twenty possible moves for each player at any given time2. You instruct the computer to look ahead five moves for each player (ten ply).
Let's look at the size of the brute-force tree at each level. For fun, we'll also look at the total number of positions in the tree (from the top to the given level).

Ply |    Positions   |  Total Tree Size
----------------------------------------
 0  | 1              | 1
 1  | 20             | 21
 2  | 400            | 421
 3  | 8000           | 8421
 4  | 160000         | 168421
 5  | 3200000        | 3368421
 6  | 64000000       | 67368421
 7  | 1280000000     | 1347368421
 8  | 25600000000    | 26947368421
 9  | 512000000000   | 538947368421
10  | 10240000000000 | 10778947368421

The result of each level being exponentially larger than the previous level is that the size of the whole tree is dominated by the bottom level. Consider the example above: the last level alone contains ten trillion nodes. The entire rest of the tree only contains five hundred billion. The tenth ply contains about 95% of the nodes in the entire tree (this is actually true at each level). In practice, what this means is that all of the search time is spent evaluating the "last" move.

Answer

So how does this relate to your question? Well, let's say the computer is set to ten ply, as above, and further it "remembers" the results of its evaluations. It calculates a move, plays it, and then you make a move. Now two moves have been made, so it prunes all the positions from memory related to the moves that didn't happen, and is left with a tree that goes down the remaining eight moves that it already calculated: 26,947,368,421 positions!

All right! So we only need to calculate the last two ply! Using our 20-moves-at-each-depth estimate, the total number of moves we need to calculate here is still over ten trillion. The positions we already calculated only account for 2.5% of the possibilities! So even by caching last move's results, the best we can hope for is a 2.5% increase in speed! At heart, this is why even if your program caches previous results, you don't usually see a significant speedup between moves (excepting cases when the computer finds a forced mate or something, of course!).

Simplification Disclaimer

There is a lot of complexity involved in this question, which is why I linked to the programming wiki at the very top and only attempted to explain the answer in broad mathematical terms. In reality, programs do generally cache parts of the tree from move to move, and there are other reasons why that's insufficient on its own--some simple reasons (e.g. a certain line might look good out to eight moves, but ends with a back-rank mate on move nine!) and many highly complicated ones (generally related to various clever pruning methods). So the computer must keep looking further ahead in an attempt to avoid making bad assumptions based on the previous move's cut-off depth.

1I'm not going to get into heuristic functions here, because that's its own incredibly complex area, but there are frequently some gains that can be achieved via position caching schemes here as well.

2An average branching factor of 20 is probably much too low.


Possible game result combinations in a FIDE tournament report file I am currently working on a small side project and want to write a chess tournament manager in Haskell. To properly set up the data structures I am wondering what the possible results of a chess game are.

The TRF (tournament report file) specification by FIDE describes the following eight (single player) results:

Regular Game

Win
Draw
Loss

Unrated Results (game lasted more than one move)

Win (unrated)
Draw (unrated)
Loss (unrated)

Forfeit Results

Forfeit Win
Forfeit Loss

Not considering (pairing allocated) Byes, this would amount to 8x8 = 64 theoretically possible combinations, most of which are probably nonsensical or extremely rare.

However, I think the combination (Draw, Loss) exists for example when one player doesn't have sufficient material to end the game and the other one gets disqualified by the arbiter. Maybe even (Forfeit Loss, Loss) exists, when player A does not arrive to the game and player B offends the arbiter and thus gets his game counted as a loss.

So which combinations exist additionally to the following obvious ones?

{(1, 3), (2, 2), (3, 1), (4, 6), (5, 5), (6, 4), (7, 8), (8, 7)}

One additional set of result combinations arises if you are unrated but about to get a rating and you play a rated player. Then, because you are unrated, the game will not be rated for your opponent but, because it forms part of your results which give you a rating, it will be rated for you.

Hence, you can add (1,6), (2,5) and (3,4)

PS I've edited the title of your question because the original was almost identical to this already answered question - What are the possible results of a game?. However you are asking something different.


Why is exchanging the queens bad in this position? Stockfish gives +6.6 to the following position.

The recommended move by stockfish is Rc1 which maintains +6.6 advantage but if I exchange the queens right away (Qxd6), stockfish gives me +5. What's the reason behind the difference (in stockfish points) between two positions?

I can understand by Rc1 we put pressure on c7 but black can exchange the queens and later can defend the pawn too. Also, as a rule of thumb, I don't usually exchange queens off the board if I can take advantage of the position. But here it seems the queens are going to be exchanged anyway.

You can find the full game here.

I think it is because 21.Rfc1 wins the c7 pawn. If black responds with a queen trade, she can't defend the pawn on c7 because white's bishop can attack a defending rook on c8 or d7.

[White "NN"]
[Black "NN"]
[FEN "3r3r/2p1kppp/B2qp3/2Qp4/6b1/PP2P3/3N1PPP/R4RK1 w - - 0 1"]

1. Rfc1 Qxc5 2. Rxc5 Kd7 3. Rac1 {and the pawn falls}

That said, the position is completely winning either way and exchanging off the queens is a practical decision that reduces risks and keeps everything under control. White has an extra piece and a passed pawn.


Josh Waitzkin chessmaster mastery quiz - spatial advantage, trading bishops Based on: Josh Waitzkin Chessmaster Strategy Section 7 - the mastery quiz.
Position:
[Event "From Josh Waitzkin Chessmaster Strategy Section 7 - the mastery quiz"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "-"]
[Black "-"]
[Result "*"]
[SetUp "1"]
[FEN "rn1qn1kr/p2bppbp/1p1p2p1/2pP2PP/4PP2/2P1BN1B/PPNQ3K/4RR2 w - - 0 1"]

White to move. I think h6, but Josh says f5. I could swear that when I did this earlier, the chess.com engine said that they were both best moves. Anyway, now it says f5 is an inaccuracy. But at least it says to do f5 after h6, assuming Black plays Bf8. (link to screenshot)

Is Josh wrong about f5? Actually Josh even explains how Black's position is bad after f5-gxh5, but gxh5 is precisely what the chess.com engine considers a best move.

For h6-Bf8-f5, the chess.com engine says that Bf8 is only a good move and that Bxh3 is best. Bxh3 costs Black 2 pawns, but I guess does relieve some of the pressure of White's spatial advantage. Is Bxh3 really the best or at least strictly better than Bf8?

I'd think maybe it would come down to preference/playing style. Or idk. I would consider Bxh3 an option if this was just 1 pawn. (Josh actually has an example earlier about giving up a pawn for the sake of relieving an outpost or spatial advantage.) But this is 2 pawns!

Edit: I actually thought of the idea that the computer is playing for time or something. By playing Bxh3, White is going to have to do some calculations about the order of moves and counting the material. Black gives up 2 pawns - 1 for position and 1 for time. Idk.

Josh says f5 ... Is Josh wrong about f5?

Yes, although black's position is terrible in any case.
If we look at the initial position and try and assess a number of things are immediately obvious:

White has a lot more space
All the pieces and all the pawns are still on the board

We can also say:

White has completed development
Black still has several pieces on the back rank and unless black can open the h file the rook on h8 is doomed to a miserable life in the near future

So, white has a very big advantage, probably close to winning.
The first two points (space advantage plus all 32 pieces still on the board) mean that it is much easier for white to move the pieces around and very difficult for black. Black's pieces get in the way of each other and there just isn't enough space in the black position for black's pieces. For black, knights are also better than bishops at the moment.
So, what can black do? Well piece exchanges would be very nice. They would create more space in black's position and make it less cramped.
Exchanging bishops would be particularly nice because, as luck would have it, the g7 bishop is occupying a square which would be great for the knight stuck on e8 and the d7 bishop is on a square which would be better for the b8 knight.
With all that in mind the pluses of h6 stand out. Bf8, the only move to not immediately lose material, firmly and further entombs the rook on h8, keeps all the pieces on the board, puts yet another piece on the back rank and moves the bishop off what is the best available diagonal for it to a dead-end square with no prospects. It becomes not much more than a "tall pawn".
What about f5? That allows Be5+, either immediately, or after a zwischenzug like gxh5 or Bc8 (clearing d7 for the knight). Let's look at what would likely happen after an immediate Be5+ and evaluate the resulting position:
[fen "rn1qn1kr/p2bppbp/1p1p2p1/2pP2PP/4PP2/2P1BN1B/PPNQ3K/4RR2 w - - 0 1"]

1.f5 Be5+ 2.Bf4 Bxf4 3. Qxf4 Ng7 4. h6 Nh5 5. Qh4 Bb5 6. Rf2 Nd7

What you have is chalk-and-cheese. Suddenly black's pieces can breathe. Black is still much worse. The rook on h8 still has no prospects but two more pieces are off the back rank and a bishop which was going to be useless has been exchanged off.

Bxh3 costs Black 2 pawns

Nonsense! I think you are making the mistake of confusing the beginner's "point count" system of 1 point for a pawn, 3 points for a bishop with the real world. There is no way the black bishop on f8 is worth anything like 3 points. Similarly the white pawn on h6 is worth a lot more than 1 point.

Is Bxh3 really the best or at least strictly better than Bf8?

Again let's try looking at a line where black follows Bxh3 with the Nxg7 immediately (the line where black plays Bxf1 is also possible although that puts black one rook exchange closer to a lost endgame) to see what is really involved:
[fen "rn1qn1kr/p2bppbp/1p1p2p1/2pP2PP/4PP2/2P1BN1B/PPNQ3K/4RR2 w - - 0 1"]

1. h6 Bxh3 (1...Bf8) 2. hxg7 Nxg7 3. Kxh3

After 1...Bf8 white has a really obvious plan to take advantage of the weak long diagonal and the monster pawn on h6 - c4, b2, line up the bishop and queen on the diagonal, mate. Alternatively, just leave black effectively a rook down (the piece on h8 is useless) and just break through in the center and mate black that way.
Going back to "beginner's point count" that rook is worth a lot closer to 1 point than 5. Once you get past beginner level you have to value your pieces according to what they can do now and in the near future.
After the sequence ending 3. Kxh3 those threats have disappeared. Black has an outpost for the knight on h5. Black might entertain hopes of playing h6 to open the h file and give the rook on h8 a purpose. Granted the position is still lost but at least there are prospects of counterplay and putting up a fight.


Can we play to reach study like positions? I am talking about a field called "Chess Study". A typical chess study is very complex, and even computers make mistakes in solving them.

So, can we play some variation which can result in such positions ?

See for example this very famous study and its commentary:

Solution to a truly remarkable study

Grandmasters and Engines Couldn't Solve This Puzzle. Then Came The Magician

So, can we play some variation which can result in such positions ?

If a study is legal, so can be reached from the starting position by a series of legal moves, then the answer to your question is trivially "Yes".

Chess players shouldn't really collude before the game to decide the outcome but when siblings or partners play each other they sometimes play an agreed sequence of moves which leads to a forced draw.

In the same way two players could work out the moves required to reach a particular study position, agree to play them and then play them.


Is there a way on lichess to see the Correspondence chess rankings? Lichess has leaderboards for every variant of chess and also every single time control of the standard variant except for Correspondence chess. Does anybody know where to see the leaderboard for Correspondence chess on Lichess and if so how?

It is funny that they do not have it listed here, as you mentioned.

I just took a guess, and changed the end of the URL to "correspondence", and got the top 200 just like the others.

https://lichess.org/player/top/200/correspondence


What are some good books on the Italian game, including the Evans Gambit and Two Knights Defense family of openings? It's been about 10 years since I played tournament chess regularly. My last rating was 1586 USCF, but it had been as high as 1717.

I recently decided to get back into playing chess, and am looking for some recommendations for a book or two on those openings as white. I've pretty much always played e4, starting the Giucco in high school and later the Bishop's opening/KGD, based on Soltis' Winning with e4. I'd prefer to be able to buy them on Amazon or the USCF site.

I would also be willing to buy a dvd or software that covers these openings.

When I looked for a similar book, the best I could find is this somewhat dated work by Jan Pinski.

This newer book by Glenn Flear apparently contains 88 pages about the italian, Evan's gambit and two knights.

If you have played the Bishop's opening before maybe this is the book for you: It advocates going into the Italian game by 2.Bc4.


Full board with full point mutual zugzwang I have two questions.

1) Is there a position with all pieces on board such that the side to move loses?

2) Is there a position with all pieces on board such that the side to move is checkmated in 1?

Regarding question two, here is one example position that I’ve made where the side to move is checkmated immediately, but the knights are still missing.

[FEN ""]
[startply "54"]

1. Nc3 Nf6 2. Na4 Nh5 3. Nc5 Nf4 4. d4 e5 5. h4 a5 6. Bxf4 Bxc5 7. a4 h5 8.Ra3 Rh6 9. Nf3 Nc6 10. Ng5 Nb4 11. Qd2 Qxg5 12. Qxb4 Qf6 13. Qc3 Qa6 14. Qh3 Rb8 15. Rg1 Qa8 16. Qh1 Ba7 17. Rh3 c5 18. Bh2 Ra6 19. f4 Kd8  20.Kf2 Kc7 21. g3 b6 22. d5 Kb7 23. Kg2 f5 24. b4 e4 25. b5 g5 26. c4 e3 27. d6 g4

Maybe, someone can improve this.

Here's a position with all pieces where either side to play loses.
Seeing why it's a loss takes some analysis.  With Black moving first, White's best plan is to open up the Bishop on f1 pinning the pawn, then Qxa4 checkmate.  This happens in most but not all lines.  Shredder evaluates the main line as +22, because either Nxc5 or cxb8=Q with leave White up a queen.
[Title "Zugzwang with full board"]
[FEN "nbb5/nqrp4/krpP3p/1pP3pP/pP3pP1/P3pPRK/4PRQN/5BBN b - - 1 0"]
[startflipped ""]

1... fxg3 (1... exf2 2. Bxf2 fxg3 3. e4 gxh2 4. f4 gxf4 5. Bh4 f3 6. Qc2 f2 7. Qxa4#) 2. Nxg3 exf2 3. f4 gxf4 4. Ne4 f3 (4... fxg1=Q 5. Qxg1 f3 6. g5 hxg5 7. exf3 g4+ 8. Kg3 gxf3 9. Bd3 f2 10. Qd1 f1=N+ 11. Kf4 Ng3 12. Qxa4#) 5. Qxf2 fxe2 6. cxb6 exf1=Q+ 7. Nxf1 c5 8. bxc7


Is there a FICS android app? I tried using this app but when I try to play online it keeps saying game over, draw something like that, the message will be on the screen forever unless I restart my phone. and it doesn't let me play online.

Is there a better app to play FICS on Android?

http://i.imgur.com/hwUfFRX.png

http://i.imgur.com/u9bYDmP.png

Mobialia Chess Free includes an FICS interface; it supports premove and interfacing directly with the console.


Don't understand why white resigned In the 2017 Women's World Chess Championship match (Round 3, game 2) between Yang Shen (white) against Nana Dzagnidze (black) I don't understand why white resigned. There was not a time control issue and it appeared that white could at least get a draw.

[FEN ""]
[StartPly "77"]

1. e4 c5
2. Ne2 e5
3. Nbc3 Nc6
4. g3 g6
5. Bg2 Bg7
6. d3 Nge7
7. Bg5 d6
8. Nd5 h6
9. Be3 Nxd5
10. exd5 Nd4
11. Nc1 O-O
12. c3 Nf5
13. Bd2 Ne7
14. Ne2 Bf5
15. Be3 Qd7
16. Qd2 Bh3
17. Bxh3 Qxh3
18. c4 b5
19. Nc3 bxc4
20. dxc4 e4
21. O-O-O Rfb8
22. b3 a5
23. Nb5 a4
24. b4 Qd7
25. bxc5 Rxb5
26. cxb5 Qxb5
27. Qc2 Qb4
28. Rd2 Bc3
29. Re1 Rc8
30. Kd1 f5
31. cxd6 Qxd6
32. Bf4 Qd7
33. d6 Bxd2
34. Qxd2 Qb5
35. dxe7 Qb1+
36. Ke2 Qb5+
37. Ke3 Qb6+
38. Ke2 Qb5+
39. Kd1 0-1

The game ended in a draw. Chessbomb isn't an official source, but it recorded the game as a draw, and the comments there indicate that the game was originally reported (by the digital board, perhaps) as a win for Black, but it has been corrected to a draw. These glitches happen from time to time.

As for the position: it doesn't seem possible for white to escape perpetual check, and black cannot force a mate and is far behind in material. Therefore, it's a draw.


Is there a checkmate in the next move? My friend claims that there is a mate in the next move. White to move and checkmate. I am aware of 3 mates in 2 variations:

1. Qd1 Kd3 2.Rxd5#

1. Qd1 Kc5 2.Qg1#

1. Qd1 Kxe5 2.d4#

But I cannot seem to find a mate in one move!

I ran it through Houdini and Rybka, both spat out the above variations.

I am aware that the engines dont normally miss these mate in 1 moves, still He seems to be sure (maybe he's wrong). Just want some 'experts' to confirm this.

It's a silly trick.  The board is upside-down!  The bottom left square is h8, and the top right is a1.  A legal move for white (but not a mate in 1) would be 1. e8=Q.  Look at it upside-down for a minute, readjust your perception of which squares are controlled by pawns, and you'll soon find a mate in 1.


Is Beth Harmon behaviour in her game vs Georgi Girev acceptable (then and now)? In S01E04 of the TV series The Queen's Gambit, the main protagonist (Beth Harmon) is competing against a young Russian player (Georgi Girev). This happens in 1966.
Following an adjournment, Beth Harmon is not spending any time at all at the table, whenever she made her move, she would wander around the hotel, looking at the game from far away. She would also sit on the side, fixing Georgi and even tapping her feet.
To me (I do not play chess, except occasionally with my children) this looks like an attempt to distract the other player, which seems to be forbidden (from the various questions I gathered in SE Chess).
Unfortunately, I could not find a publicly available fragment of that episode, but this behaviour was never seen neither before, nor after that specific game.
I understand that there is a lot of subjective elements in the interpretation of "distraction", so would Beth's behaviour be acceptable in 1966 and today?

I think the idea was that Beth felt uncomfortable because for the first time she was no longer the young prodigy. Here was someone else younger than her competing at the same level. How would she respond?
This scene was, I understand, to some extent improvised. It seemed to show also Girev’s relative mental balance compared to Beth, at that point in her psychological trajectory. Her arrogance here foreshadows her later fall, after which she did some growing up.
Even today there are mean players, for example the one described in this chess.com post. This kind of thing is clearly against the Laws of Chess but there will be those who continue to behave like this if they find they can get away with it, particularly when facing young and relatively inexperienced opponents. Personally, the individual described seems to be horrid, and I would hate to be taught by them.
The role of the arbiter is essential in policing behaviour, particularly where young players are concerned.


Does memorizing chess games improve chess ability? It is common for strong chess players to have chess games in memory. Is this because it helps to memorize chess games?

I would switch the cause and effect. Strong players have many games memorized because chess memory improves with strength, not because the memorization made them strong. I am not saying that memorizing games is useless but I think that there are more efficient ways to improve.


How many new openings did Fischer use against Spassky in 1972? Bobby Fischer's openings in the 1972 World Chess Championship are said to have taken Spassky completely by surprise:

Fischer played always e4 as his opening move, in football terms he had a very limited playbook, he always played the same opening moves, and (in 1972 WCC) he defied the Russians (and the world) to beat him. From the age of 12 - 29, he played exactly the same opening moves.

In the 1972 World Chess Championship, how many new openings did Fischer use against Spassky, and across how many games did he use them?

Fischer kept changing the openings quite a bit:

Game 3 (black) he played a Benoni (slight surprise).
Game 6 (white) he played c4 for the third time in a serious game (transposed to -QGD).
Game 8 (white) he played c4 again and it was a proper English
Game 9 (black) Queens Gambit Declined - Semi Tarrasch (slight surprise)
Game 10 (white) he played c4 again (transposed to QGD Orthodox)
Game 13 (black) he played Alekhine's defense.
Game 14 (white) he played c4 (QGD)
Game 17 (black) he played the Pirc Defense for the first time in his career
Game 19 (black) he played Alekhine's defense again
Game 21 (black) he played a line of the Sicilian (Taimanov) that was new to him.

You can check the list of opening here:
https://en.wikipedia.org/wiki/World_Chess_Championship_1972
And here are the list of Fischer's most played openings:
https://www.chessgames.com/perl/chessplayer?pid=19233


Plans for black when White castles short in the Sicilian dragon What are the plans for Black when White castles short in the Sicilian dragon? Very broadly speaking I am thinking of two plans.

Go for a King's Indian like kingside attack with e5 played at a suitable time.
Do a6-b5 and generate queenside pressure.

Is one more sound than the other? Or is it just a question of style? What should I be aware of before deciding which one to adopt?

Pretty much any open Sicilian when both sides have castled King-side Black can seek counter-play against the center by undermining the Knight on c3 with b5-b4 ideas or if allowed Rxc3 exchange sacs.

Also thematic is trying to play d5.   Bent Larsen said something to the effect that the Sicilian was a positional trick where you trade a wing-pawn for a center pawn, then with 2 center pawns vs one you will be able to eventually take over the center.

I haven't seen games where Black has prospects of a king-side attack in a Dragon where White castled King-side.  Usually White is trying to attack there with f2-f4 etc.


Are connected doubled (4 pawns on 2 files) a weak structure? It seems to me to be a very solid structure that can play very good in the endgame.

Example: pawns on c2, c3, d2, d3.

It is a solid structure indeed, avoiding one of the most important weaknesses of doubled pawns, which is that they're generally hard to protect. Also, they're less easy to block than just a c- and d-pawn, since the backward pawns can attack enemy pieces on the blocking squares.

However, this structure only influences the b-, c-, d- and e-files, while a 'regular' connected pawn structure influences 6 files. Such a structure is also more likely to be able to force breakthroughs. Everything depends on context, as user1583209 notes, but in general it's better not to have doubled pawns.


What are the options to automatically identify games where the first move played was the best by a margin? Let's imagine I have a pgn file with each game starting from a tactical position, and I want to identify the games where the solution was the only one. Basically an engine would have to evaluate several possible moves, and the evaluation margin between the first best move and the second best move would have to be above a certain threshold (e.g. >3.00 pawns). I do not want to load up manually every game and look at the engine evaluation - that's the step I am hoping to eliminate.

I am interested to hear of any GUI based solutions, or even script based (e.g. modifications to this - http://sourceforge.net/p/scid/mailman/message/29220017/ - I like this script, but can't get it up and running easily because SCID TCL interpreter on Windows seems to come without Expect package ...)

It is not too difficult to do this with a python script:
You basically start the engine as a subprocess and communicate via "uci".
I'll post some not very pretty code snippets and try to explain what you have to do:

engine=subprocess.Popen('./stockfish-5-        64',universal_newlines=True,stdin=subprocess.PIPE,stdout=subprocess.PIPE,)

def put(command):
    print command
    engine.stdin.write(command+'\n')

    if command!='quit':
        engine.stdin.write('isready\n')
        while(True):
            text=engine.stdout.readline().strip()
            print
            print text
            print
            if text == 'readyok':
                return

def get():
    engine.stdin.write('isready\n')
    while(True):
        text=engine.stdout.readline().strip()
        print text
        if text == 'readyok':
            break
        if text !='':
            print text

def getResult(depth):
    Result=[]
    while(True):
        text=engine.stdout.readline().strip()
        liste=text.split()
        if text[:22]=="info depth "+str(depth)+" seldepth" and liste[15]=='1':
            Result=[]
        if text[:22]=="info depth "+str(depth)+" seldepth":
            Result.append(text)

        if text[:8] == 'bestmove':
            break

    Scores=[]
    for line in Result:
        liste=line.split()
        Scores.append(liste[7])

    return Scores

def Game_Analysis(game):
    scorestring=''
    moves=''
    for x in range(len(game)-1):
        moves+=game[x]+' '
        command='position startpos moves '+moves
        put(command)
        get()
        put('go depth 15')
        Scores=getResult(15)
        for score in Scores:
            scorestring+=score+' '
        scorestring+='\n'
    return scorestring

get()
put('uci')
get()
put('setoption name MultiPV value 20')
get()

print Game_Analysis(game)

put('stop')
put('quit')

So, get() and put() are for communicating with the engine.

put('uci') starts the dialog.

put('setoption name MultiPV value 20') tells the engine to return the best twenty moves. (In your case you really only need 2)

command='position startpos moves '+moves
put(command)  This sets up the position, unfortunately the moves aren't pgn but in uci-format. So you'll probably have to transcribe or use FEN.

In GetResult() I extract the 20 best scores of the position. Then you only need to look for a big difference between move one and move two.

Game_Analysis(game) extracts the 20 best scores for every position in a game, here given as a list of uci-formated moves.

To deal with the uci-format and really understand these commands you should have a look at the uci=Universal Chess Interface.


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.


How to deal with people getting help on board We all had this situation where our opponent have this fide master friend and just happen to stand next to him, whisper him things while pointing your chessboard.

I've never had the guts to call it out (that would make a mess out of no proof accusations) but that usually mess up my game as my anger take over my concentration.

I'd like to know if you've met this situation and how you dealt with it, or what would be the official way to deal with it.

Please consider that calling out referee might not be the best solution : as I said, there's no proof, and it's easier said than done to call a cheat when there's no evidences.

What you describe has never happened to me personally, but I would have no qualms of making a complaint in this situation - either by calling the arbiter (in the case of a tournament) or my captain (in the case of a league match). What you describe is clearly unacceptable conduct in any rated game.

To illustrate how little is needed for an issue to be taken seriously: I once played a kid of about 6 years old - he was a good player (on my level at least), but he struggled to write down the moves properly. His dad came over and started to correct some of his notation. My team captain immediately complained to his team captain, and the dad was asked to leave the playing area. The question of proof was not on the table - just the fact that one person may be uncomfortable about something is enough for a referee to impose strict playing conditions even if no misconduct actually occurred.


Do different nationalities have "notably" different play styles? In chess, noting the more common countries I've played (Indian Russia, Australia, France, US,  China, Japan etc) I've noticed some similarities in their play style. Like how Japanese players, from what I've seen, play aggressive pawns; France and US play the more typical tactics, China doesn't play gambits, and overall isn't rich in strategy.

While these may just be coincidence, Is there enough similarity within a nationality that it's notable?

Consider this quote from wikipedia regarding the Soviet Chess School:

  The main contribution of the Soviet School of Chess was not the style of players but their emphasis on rigorous training and study of the game, i.e. considering chess a sport rather than an art or science.

Emphasis is mine.

Given that chess is taught as a school subject in Russia, then this points to there not being trends in chess style by country.

Moreover there seems to be little evidence that openings named after regions are done so because of their popularity there. If this were the case, then Scandinavians would tend to play the scandinavian-defense, which has a different style to the italian-game. In fact, the Scandinavian is called such because it was first seriously analysed by Scandinavian masters.


What is the maximum number of passed pawns in a position? Something I have wondered about recently is the maximum number of passed pawns that is theoretically possible. What is the answer, and the fastest way to achieve that result?

EDIT: record is now 20.0 moves! (See below.)

If we like pawns undoubled...

[title "16 non-doubled passed pawns in 21.0 moves"]
[fen ""]
[startply "42"]

1. g4 h5 2. g5 Rh6 3. gxh6 g5 4. h4 g4 5. b4 e5 6. f4 e4 7. Nf3 exf3 8. e4 f5 9. e5 Qg5 10. Nc3 a5 11. Ne4 fxe4 12. c4 a4 13. Qb3 axb3 14. a4 b5 15. a5 d5 16. c5 Bd6 17. cxd6 c5 18. Ra4 c4 19. d4 Na6 20. hxg5 Nc5 21. dxc5 bxa4 *

If we like all our pawns doubled, there's just a small improvement possible...

[title "16 passed pawns (all doubled) in 20.5 moves"]
[fen ""]
[startply "41"]

1. a4 b5 2. a5 d5 3. c4 h5 4. Ra4 bxa4 5. c5 e5 6. g4 Bd6 7. cxd6 c5 8. e4 f5 9. Ne2 h4 10. Ng3 hxg3 11. h4 Rh5 12. gxh5 g5 13. Bc4 dxc4 14. d4 f4 15. Be3 Bf5 16. exf5 fxe3 17. f4 e4 18. d5 Qb6 19. axb6 a5 20. b4 g4 21. b5 *

But best of all, curiously, is if we mix doubled and undoubled...

[title "16 passed pawns in 20.0 moves!"]
[fen ""]
[startply "40"]

1. d4 c5 2. f4 e5 3. f5 d5 4. Bf4 Be6
5. fxe6 exf4 6. e4 f5 7. e5 c4 8. Bd3 Bc5
9. dxc5 cxd3 10. c4 a5 11. b4 a4 12. Qb3 axb3
13. a4 b5 14. a5 h5 15. g4 Rh6 16. g5 d4
17. gxh6 g5 18. h4 g4 19. Ra4 Qg5 20. hxg5 bxa4 *

I don't think this can be beaten, and the other 20-move positions are quite narrowly defined: the captures from a file to h file must be R,Q,B,B,B,B,Q,R/N.


ChessDB databases import I've just installed the ChessDB software hosted at SourceForge. While discovering the software I see that the databases that come with the software are empty  and I would like to know how to import new databases of openings or endgames,...etc.
Any help greatly appreciated !!

He (author) explains how to go about getting this here. The sourceforge game databases are available here

Update:
 To go about downloading the database from the second sourceforge link provided above, the author provides instructions here (can do it directly form ChessDB's Tools menu).


How to notify check when a player leaves himself in check I'm learning to play chess.

Twice we had a situation where the white player moved a piece that was blocking the black Queen from checking the white King. There was no move available to announce "Check".

What is the proper procedure here?

It's not technically a check since Black wasn't making a move to check White's king. White made an illegal move that placed his King under attack.

Black should mention that White made an illegal move, getting White to take the move back and play something else. If you're playing in a tournament, you could call the arbiter over and say White made an illegal move (often 3 illegal moves = forfeit).


How can someone become the greatest chess player like Magnus Carlsen? How can someone become the greatest chess player like Magnus Carlsen?

I have been playing chess since I was 12 years old, but still I am an average chess player.

Does it take genetics to become a Super GM like Magnus Carlsen, Garry Kasparov, or Vishy Anand? Or have they all followed some path towards their greatness?

What steps could I take or attributes should I possess in order to become the number 1 rated player in the world?

Talent: Generally the role of talent in chess is vastly overrated, but for those at the very top anecdotes of impressive memory feats are quite common. (Like Carlsen learning hundred of statistics about norwegian municipalities as a four year old, or Fischer repeating a phone call in islandic verbatim, although he didn't understand a word, etc.)
Early exposure: The vast majority of the top hundred GMs nowadays learned to play chess before they turned ten. Often even before they turned six. Early exposure is important for chess moves and concepts to become completely ingrained in your brain, just like the grammar and vocabulary of your mothertongue is.
Hard work: Even those players that are allegedly lazy spend an incredible amount of time on chess. Becoming a strong chess players requires a huge amount of knowledge and abilities. The earlier you start, the harder you work and the more directed this work is, the younger you will still be when you have acquired the knowledge necessary to be a Super-GM.
Drive: If you have the abilities and the knowledge to play on a 2800 Elo level, it still doesn't mean that you actually play on that level. Additionally you need the energy and will to win, that allows you to put every ounce of your ability into every game you play. Some people claim that motivation is the main reason the playing level generally drops after you hit 40.

So the steps to become a Super-GM are actually quite simple: Start at age 4, train chess every day for 6-8 hours under the direction of an experienced trainer, compete regularly against slightly stronger opposition and be born with an exceptional memory and a killer instinct.


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.


Can a threefold repetition be claimed in a blitz game? If so, how? Can one claim a draw by threefold repetition in a blitz game when no score of the game is being kept? If so, how?

Once, in a blitz game, my opponent was simply trying to run me out of time. At a certain point in the game, I pointed out to him that he brought the same position on the board thrice and so I offered a draw, but he just ignored. There was nothing I could do to PROVE the threefold repetition occured and so had to carry on with the game and eventually lost on time.

It's hard, and I've never seen it done correctly, in the sense that it's the way I was taught it should go:

During slow games, once the players are not writing down their moves anymore because they are close to a game control, the arbiter should write down the moves as well to help with reconstructing the game after a flag falls (say to check if the 40th move is reached), or for claims like this. He can do so as well with blitz games, or appoint a temporary assistant to do so for him. It's just not usually done.

So you can stop the clocks and ask the arbiter to start recording moves, or appoint an assistant. In theory I think he should do that, and then when a threefold repetition occurs after that and you claim, the arbiter can check your claim using his notes.

But in practice, I think most arbiters will be too busy and too unfamiliar with these sort of rules to do that.

And of course, if you get the claim wrong, the opponent gets 3 minutes extra on the clock. Pretty hefty in blitz.


Is it possible to be a good chess player without theory? I would like to be a very flexible chess player as in never in a uncomfortable position unless I did something to deserve it such as a blunder. I've concluded that the only way to do this is to avoid as much theory as possible? I feel like I might rely too much on theory these days (is there a way to tell if I really do rely on theory too much?) and would like to make a change but I'm not sure how to go about it.

Well, depends on your definition of theory and good. If you mean, never really studying specific things then you will be lacking in a few areas. Notably:

Openings. You will struggle at a high level without theory unless you are Magnus Carlsen. Most top level Grandmasters have memorised thousands of opening lines, and understand them extremely well. If they did not know these, they might be able to work out the correct answers, but they would use a lot more time to do so (which would be a very significant handicap). The computer age was leading towards theory being critical for most games, but Carlsen plays many novelties, showing that opening theory is not completely necessary.
Endgames. You might be able to work it out for yourself, but again, you'd have to be a super genius to naturally get this at a top level. Endgames have many specific things that would be much easier to learn if you just studied the theory. Without theory, it will take you much longer to learn the same thing.

There are probably more things. However, there are things that you can gain without theory:

Tactical Sense. Tactics don't technically have much theory behind them, as there isn't a HUGE amount of concepts to learn (pins, skewers, etc). It just requires you to improve efficiency in your brain, and calculating power. This is easier said than done, without a good position, you'll find that you don't have many tactical opportunities available to you.
General game sense. If you don't use much theory, and alternate your openings, you will probably be more versatile. Also, until a high level (>2000), you will trip up your opponents because you'll be playing off-book.

If you're looking to avoid theory (which I do), just alternate your openings! Have a cycle between your openings. Each game as black, alternate between c5, d5, e6, c6, etc. Don't choose too many, just pick ones that suit you. If you want to play quiet games against e4, play d5 or c6. If you want more intense games, e6 or c5. It mixes it up, and you learn the different plans for different openings.


Is it better to start without a queen or without any pawns? I think that this question really can be answered rigorously with good analysis. It is opinion-based, but not completely since some results in this direction can be obtained, and strict and general guidelines can be given, along with good heuristics and reasons for the advantage of one or the other side. So, let us go straight to the description of a question.
Some of you wrote about some system of points I really did not know of, that assigns values to figures, according to their "strength". Of course, it all depends on the positions in the game and on the tactics and strategies, but, I have a legal question to ask.
Suppose that two players are starting the game, and that they are equally good (in this context, meaning that all the strategies that one player knows of the other one knows too, and vice-versa). One is starting the game without 8 pawns and with a queen, and the other one is without a queen and with 8 pawns. Who, generally, has the advantage?
[FEN "rnbqkbnr/8/8/8/8/8/PPPPPPPP/RNB1KBNR w - - 0 1 "]

I think that this can answer this can be determined through very rigorous and sufficient analysis. It seems also that there is a tendency to favor the side with a queen and without pawns, but I do not see exactly why, and do not understand the reason for that?
Can it be explained, with sufficient analysis of the problem, the main issues of both sides, with givem heuristics about what would (or should) happen later in the game? Is there really a real advantage for one side, and why?
Edit: Now, after some thinking, I am of the opinion that this question is harder than it might seem to be, and, although much can be written and said about this starting configuration, I think that general consensus will not be so easy to establish. I am of the opinion that the White one is, generally, in advantage, but am unsure on how to prove that, and, someone with much more experience and games behind him/her could obtain some precise and thorough analysis. If someone is in close contact with masters of chess, and can ask them about an opinion, we could be closer to some conclusions. As for me, the more I think about this problem, the more hard it becomes to me.

Other than the computer evaluation proving that the Q is better, the biggest problem here is that black basically starts out fully developed since his pieces already have amazing scope, and can quickly coordinate his forces, and attack.


What Chess board companies are the most reputable? As a follow up to my original question What are the characteristics of a good chess board? I was wondering what companies are the most reputable for Chess board construction.  Since I am just a beginner I am curious at lower cost beginner boards, but also in other boards that I might want to splurge on one day if I really get into Chess.

The standard vinyl board is hard to beat for everything except showing off a chess set.  You can get them for cheap from the USCF or from any other purveyor of chess gear.

Here's one from Cajun chess for $4.  I bought a few sets from them. I like them.

Looks like tournament-sized wooden boards begin at $50.


What is considered the current main line for Black against the Smith-Morra gambit? I am referring to main lines where the pawn sacrifice is accepted.

Most reference books will give the main line as

1. e4 c5 2. d4 cxd4 3. c3 dxc3 4. Nxc3 Nc6 5.Bc4 e6 6.Nf3 d6 7.0-0 Nf6 8.Qe2 0-0 9.Rd1 e5

Followed by either 10.Be3, 10.h3, 10.Bg5, 10.a3 or even 10.b4.

They usually evaluate this 'main line' as a dynamic equality.

Repertoire books often offer other ideas for Black (with...g6, or ...Ne7, or ...Bb4, or ...a6 and ...b5, or 3..e5 or refusing the gambit right away).

[fen ""]
1. e4 c5 2. d4 cxd4 3. c3 dxc3 4. Nxc3 Nc6 5.Bc4 e6 6.Nf3 d6 7.O-O Nf6 8.Qe2 Be7 9.Rd1 e5


What squares are the most active for bishops? For a beginner:

Where are bishops mostly exchanged or placed?
Where are knights mostly exchanged or placed?

The f3/f6/c3/c6 tend to be where most knights are exchanged. That is because in beginner play, if the opponent tries to push the pin with h3/h6/a3/a6, the person who has pinned the knight with the bishop typically exchanges, and this tends to be a beginner fault..


Unusual sequence of opening moves in the Open Ruy Lopez with 6.d4 Be7 As title above,could someone kindly explain the tactical highlights of the rather unusual sequence of moves arising with the recent interpretation of the Open Ruy Lopez with 6.d4 Be7?
[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Nxe4 6.d4 Be7 7.Re1 b5 8.Rxe4 d5 9.Nxe5 Nxe5 10.Rxe5 bxa4

For example, why isn't White simply retreating the Bishop to b3 with 8.Bb3 ? Why 9.Nxe5 instead of simply retreating the Rook with, for example, 9.Re1 ? Why isn't Black taking the Rook with 9...dxe4 ? And so on.

I think the first step is to look at the analysis of the first 9 to 10 moves;
It is all pretty standard for the first few moves.

e4 e5 2. Nf3 Nc6
Bb5 a6 4. Ba4 Nf6
O-O Nxe4 6. d4 Be7
Re1 b5
Rxe4 {[#] And now Bb3 would win. C84: Closed Ruy Lopez: Unusual White 6th moves.} d5
Nxe5 Nxe5
Rxe5 {Threatens to win with Bb3. White is better.} bxa4

So looking at the logical developments;
   [FEN ""]
   1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Nxe4 6. d4 Be7 7. Re1 b5 8. Rxe4 d5 9. Nxe5 Nxe5 10. Rxe5 bxa4 11. Qe2 c6 12. Bd2 Be6 13. f4 g6 14. Nc3 a3 15. b3 Bd6 16. f5 gxf5 *

11. Qe2 {Adds an extra defender to the e5 rook. Provides a potential battery into blacks territory on the open e-file.} c6 {adds a defender to the isolated d5 pawn.}
12. Bd2 {Unable to develop to g5to target the e7 bishop. Black can easily counter with f6 bother attacking and defending. Idea to develop to Bb4} Be6 {Adds and extra barrier to whites e5 rook and e2 queen. provides additional support for central pawns as well as being supported / supporting the f7 pawn.  This also unpins Be7 which has good
attack opportunities on f6 primarily.}
13. f4 {Adds an additional defender. Can be pushed to harrass Be6} g6
14. Nc3 {Try to capture some lazy material on a4} a3 {White can capture but doesn't want to open up the b file or stack pawns on the a file}
15. b3 Bd6 {Blacks bishop finally back in the game. Threatens capture of the e5 rook}
16. f5 {Stalling move. If black plays Bxe5 white can capture fxe6 which forces black to respond fxe6 followed by Qxd5. Material is largely even} gxf5 *
End Result:
Positions are equal , arguable that white has minor advantage. Considering white had a slightly better position at move 10, and is only down a pawn I believe. Is an interesting
Some Master Games from this position
First Notable game I can see in my Database.
Lasker vs Tarrasch (1916) - https://www.chess.com/games/view/15756559 : In fact theres two games with this exact position from the same year.
More Recent Games;
Caruana vs Carlsen (2018) - https://www.chess.com/games/view/15606031
Nakamura vs Caruana (2019) - https://www.chess.com/games/view/15656519


Looking for a good and non main line variation against the Sicilian I am looking for a nice variation against the Sicilian, which is a little bit aggressive but mainly not part of the main line like Nf3, d4, b4 or c3 after e4 c5.

The thing is, I don't want to learn 20 variations, which I have to do if I play the main openings.

Which one do you like to play / recommend me?

It's a bit difficult to recommend an aggressive line that doesn't fall into the variations that you listed. However, I believe there is an option that may suit your tastes. The Rossolimo with 2. Nc3 is venomous choice that's played at the highest levels and contains many lines that are quite dangerous for black. Here's one of the opening traps:

[FEN ""]

1. e4 c5 2. Nc3 Nc6 3. Bb5 Nd4 4. Bc4 e6 5. Nge2 Nf6 6. d3 a6 7. O-O d5 8. exd5 exd5 9. Nxd5 Nxd5 10. Nxd4 cxd4 11. Qh5 Be6 12. Re1

I recommend that you look more into the opening yourself and discover some more interesting lines.


How to determine checkmated positions using DOS/CMD, from numerous FEN/EPD chess positions? I have a collection of checkmated chess positions, in FEN/EPD format.
Most of the time, each of these positions contains some useless pieces, that I really want to remove, in the aim of getting cleaner schemes.

Then, I'm searching for a batch possibility to check if my whole chess collection is checkmate or not. Ideally, it would be a tool/solution using DOS/CMD, because I have to clean many FEN checkmates.

I've googled for various DOS chess tools, but in vain. I also searched to use some chess engines (under cmd), Arena/WinBoard, EPD2Diag, PGN-Extract, etc. but also without success.

Here are two examples:

[FEN "3q4/6b1/4k3/4r3/3p2Q1/B1N1R3/5R2/6K1 w - - 0 1"]

[FEN "1K6/1b6/1b6/1P6/7r/7p/7Q/4qN1k w - - 0 1"]

Here, it's obviously both checkmate for White, but knowing I have few hundreds of others, how can I get a DOS batch possibility to check all in once?

I don't know if any such tool exists. If you want to program yourself you need to watch out for:

Change of mating theme: If you remove pieces you might get new/different mates, e.g. in:

    6rk/5Npp/8/8/8/8/2K5/7R b - - 0 1

if you remove the white knight and the black pawn on h7 you have a new mate, which might not be desirable.

Impossible positions: If you remove pieces you might end up with positions that cannot be reached in normal play. This can be as easy as positions where three pieces attack the king at the same time, but it can also be a lot more difficult. So in addition to checking for mate, you also need to run some retrograde analysis to check whether the position is legal


Is there an engine that finds the best "practical" move? A standard chess engine will find the move it considers best assuming best play from both sides. But this move might lead to an insignificant advantage or a tricky line that can easily result in mistakes for a human player of a specific ability. Is there a program that finds the best "practical" move for e.g. intermediate players? For example, it might pick a move that leads to a very strong attacking position where the opponent will most likely make a mistake, even though it could be defended against with perfect play.

You're describing something that's very similar to contempt. The idea with contempt is that if you keep more dynamism in the position, a weaker opponent is more likely to make mistakes that you can then exploit. Therefore, given two moves that yield similar evals, an engine with high contempt score will choose the one that keeps more dynamism in the position. The current-strongest traditional engines all have contempt implemented (example for Komodo).

The danger of contempt is, against a strong opponent, high contempt can get you killed - you are after all forcing the engine to play a weaker move just to keep the game alive.


What is the name of this mating pattern? Recently I delivered the mate shown below. Does it have a name?

[fen "1r5r/2p3pp/2R5/1pkPpp2/2b1P3/2K2P2/6PP/R7 w - - 0 1"]

No, it's rather unusual (but beautiful!) to mate a King in the middle of the board. Because it's rare, probably nobody (that I know of) has coined a term for it yet.


Are gambits a good way to improve tactical awareness (for strong amateurs)? As gambits are all about activity, initiative, and attack, should I start playing gambits to increase my awareness and all these things?

Sure! Playing a highly tactical position that you aren't used to can help you train your tactics, but there are plenty of non-gambit alternatives that are also rich in tactics (think for instance of most lines in the Sicilian defense)


Where to find specific endgame practice exercises/puzzles/practice bots? I'm looking for a set of exercises (contained in a book, website, or chess engine) where I can practice what I know in regards to rook and pawn vs. rook endgames. I could find a friend to randomly place pieces on the board for me, but I don't see what would be in it for her or him.

Something ideal would be a website that displays a puzzle that I can solve, but the pawn would have to be on the a- or h-file and 7th rank. If I can set these parameters while randomizing the position of the rooks or king, that would be great.

Where can I find such a website, and if there isn't any, how can I create such an object? The object would set the pieces randomly on the board, with the exception of my selection. So if I select the pawn to be on a7 and the king to be on a8, it will randomly place the other pieces elsewhere. I'm only interested in the following pieces being on the board: A pair of kings, a pair of rooks, and one pawn.

If you're looking for a truly random position, I'd just roll an eight-sided die a couple of times to determine the column and row of each piece. (If the position is illegal, just reroll.) You can then enter the position into a chess program and play against the engine. Here's an online dice roller in case you don't have physical ones, the one you're looking for is called the d8.

If you're looking to practice key positions in KRP vs. KR specifically, you'd probably be interested in John Nunn's Secrets of Rook Endings. I forgot how this book is organized exactly, but it contains almost all positions in this ending which are worth studying.


Why did black choose 1... Kxg7 instead of 1... Rfe8 in this puzzle? I have a doubt with a puzzle that I solved recently. The proposed solution for that puzzle is as below.

[FEN "r4rk1/pp4np/2n1bppB/qNQ1p3/8/6P1/PP2PPBP/R4RK1 w - - 0 1"]

1.Bxg7 Kxg7 2.Bxc6 bxc6 3.Nd4 Qxc5 4.Nxe6+ Kg8 5.Nxc5

But instead of choosing 1... Kxg7, if black has chosen 1... Rfe8, I think it would have given black a better position as below.

[FEN "r4rk1/pp4np/2n1bppB/qNQ1p3/8/6P1/PP2PPBP/R4RK1 w - - 0 1"]

1.Bxg7 Rfe8 2.Bxc6 bxc6 3.Nd4 Qxc5 4.Nxe6 Rxe6

In a comment below the puzzle, someone has mentioned that if black doesn't take the bishop, it loses a minor piece. What is that referring to? Is there any specific reason for black not choosing 1... Rfe8?

I've done this puzzle today too! It's Chess.com's puzzle of the day =)

I have analysed it with Houdini 3 Pro. Here is what it says after 1.Bxg7 :

1...Kxg7 : +5.07
1...Rf7 : +5.43
1...Rfe8 : +5.52

After 1... Rfe8 your move 2. Bxc6?? is a blunder and lose a lot of White's advantage (White is still probably winning but not by much). Houdini evaluates it as only +1.96

The killer move is 2. b4!! which Houdini evaluates as +5.52

It will continue: 2... Nxb4 3. Bxf6 Rac8 4. Qxe5 Bc4 5. Be7

(It's pretty much forced, all other Black replies are much weaker. 3... a6 is answered by 4. Qc7 ; while 2... Qd8 is answered by 3. Rfd1)

Then here are three lines:

5... Bf7 6. Bxb4 Qxb4 7. Rab1 Qxb1 8. Qxe8+ Rxe8 9. Rxb1 Rxe2
5... Qd8 6. Bxd8 Rxe5 7. Nd6 Rxd8 8. Nxc4
Rxe2
5... Qxb5 6. Qxb5 Bxb5 7. Bxb4 Bxe2

According to the omniscient Houdini the move 1...Rfe8 is technically slightly inferior to 1... Kxg7. But I think you are right: if it was a practical game, Black should play 1... Rfe8 because it gives White a harder time at finding the correct optimal continuation.

Trading Queens with 1... Kxg7 simplifies the position and makes it very easy to win for White. But after 1... Rfe8 the position is still complex and White may make a mistake. I believe Black's best hope is to play 5... Bf7 6. Bxb4 Qxb4 7. Rab1 Qd2?! which keeps the Queens on the board.


What's the most efficient way to get from 2000 to 2300? I'm a hobby chess player with a rating of about 2050 FIDE. I would like to get to 2300 in the long run, but I don't have too much time on my hands, since I'm a busy university student and I also have other interests.
What I'm looking for is some kind of training plan that I can follow and that will eventually pay off. That comes with a few questions, of course.
 1. What should I train?
 2. How much should I train each week?
Each week, I have about 4-5 hours available for chess training. My current idea is that I spend most of that on tactics, and some of it on reading chess books on strategy. What do you think?

Once you've reached a skill level like that one you have, it really depends on what you current flaws are!

The first step should be a deep analysis of your games (I mean a real self-made analysis, not checking what Stockfish thinks of each position) Try to find the reasons why you lose the games you lose.

But, in general, for a 200+ rating point increase, you will have to work to some extent on all aspects of your game, with tactics and strategy (static and dynamic) being most important, but I'd also have a look at fundamental endgame theory as wel as build a solid opening repertoire.

Also, is it a possibility to hire a coach?

Good luck!


Why is this a better move? Playing on chess.com against the first advanced bot, "Antonio", I've lost a game and looked at the analysis.
The following is the state of the game not far from the beginning, where I had done only those moves that the engine considers either "book" or "best":
r1bqkbnr/pp3ppp/n1p1p3/8/3PN3/5N2/PPP2PPP/R1BQKB1R w - - 0 2
At this point my move was c3:
r1bqkbnr/pp3ppp/n1p1p3/8/3PN3/2P2N2/PP3PPP/R1BQKB1R w - - 0 2
which the engines deems "excellent", whereas the "best" move would be
r1bqkbnr/pp3ppp/n1p1p3/4N3/3PN3/8/PPP2PPP/R1BQKB1R w - - 0 2
My question is, why is this a better move? What advantage does it give to me? Is it in the short term?

Maybe because it threatens BxN PxB, Nxc6, gaining a pawn? Therefore it reduces the range of moves that Black can play this move. Qa4 can then follow up (to a move like Ne7) to place pressure on the A knight and the C pawn.
It also allows threats like Qf3 or Qh5, whose refutations might weaken Black's pawn structure?
Just speculating.


Do any national chess bodies not strictly follow FIDE rules? There are some subtle differences in the rules of chess used in different un/rated competitions. For example, chess.com never considers King + Bishop sufficient mating material (specific example here).

Do all national chess bodies (e.g. AICF, FEDA etc) strictly adopt FIDE rules, or do some make their own variations like chess.com does?

The more 'human' way of asking the same question is like this: Is chess played by exactly the same rules around the whole world, or are there subtle variations in the rules of the game from country to country, as is the case with some games/sports e.g. rugby union?

I do not know the rules for every country, but if the USCF and ICCF are any indication, most bodies have their own tweaks to tournament rules. The rules for the actual piece movements are consistent.

The exception is when a tournament is both nationally-rated and FIDE-rated, then FIDE rules take precedence.


How do you analyze master games without annotations? I am starting to analyze master games more often because I never really do. But I play openings most masters don't and most games with these openings don't have many annotated games. So, how do you analyze master games without annotations?
I play at around 1500 USCF strength. I got good from just playing, but I have been really studying lately, endgames and tactics. I don't play into the mainline openings, but I have been slowly going into the mainlines like the Bird variation in the Ruy Lopez and the Traxler Counterattack. I want to study the master games now because everyone says that's one of the fastest ways to improve. I don't really want to study the games that play into the mainline until move 23 and the last 100 moves with 2,000 years of annotations. I just want either a brief explained game from a master or a non-annotated game since I don't have much time on my hands.

How? Yourself :-)
This should not discourage you from getting the help of an engine - afterwards §. Also, to me it seems critical to what end you are analyzing master games. There are many answers to this question, almost as many as masters. You analyze a Morphy game? Great choice, learn how opening sins (especially underdevelopment) are punished mercylessly. You analyze a Tal game? Great choice, delve into the variant chaos and show this Rigan swashbuckler you can defend better than his lame-o opponent. :-) You analyze a Capablanca game? Great choice, learn to crush an opponent from an almost equal position without him understanding what hit him.
Generally, it's far easier to analyze with regards to tactics. When it comes to positional play, methinks without annotations you are lost as a beginner. I suggest to edit in your learning goals into the post. It never hurts to analyze GM games but it will make the answers more precise.
§ Dangers of meta-playing, especially when engines are present. From Haukes infinite surplus of chess stories. I played a training match with a kid and his trainer. We were post-morteming. The trainer (having an engine): White has a brilliant move here. I, not even thinking for a second: e5. The trainer is baffled (especially because I'm a strong and very original player who nuked many a GM, but never reached even IM strength). "How did you know?" (He knows I can't calculate even remotely.) "Easy, it's always e5 in the Sicilian!" (In the Bxf6 gxf6 Najdorf, for the experts.) "And since you gave away the fact that a move exists, it is good and I don't see any peculiar one, it must be e5." Don't let such habits sip into you, you don't have an engine when you are playing a tournament.


Am I allowed to call the arbiter on my opponent's turn? My opponent, in their turn, was distracting me making annoying sounds. However, the arbiter said that I should wait until it's my turn when I called them. Is this correct?

You are absolutely allowed to call the arbiter when it is your opponent's turn. There are any number of reasons why this would be necessary.

To start with the most prosaic, you have filled your scoresheet and
need another one.
You are feeling unwell and need medical assistance
Your opponent has picked up a piece but isn't sure where to move it to. They are holding the piece above the board, obscuring your view of the board and distracting 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.


Why does AlphaZero implement time steps in its input layers? I'm trying to build my own chess engine using neural nets, and have been researching papers from Deepmind about their algorithm implemented in AlphaZero. Since chess is a game with perfect information (meaning the only unknown information in the game is what's going on in the opponent's head) and that each action resulting from a game state does not depend on the previous actions (except castling rules for example), why does AlphaZero have an 8-step temporal implementation in its input layer? In other words, its NN, aside from looking at the current game state, also looks at states from 8 previous moves in order to make a decision? AlphaZero's paper didn't have a say about this.
Also, the architecture that I'm trying to build is not a Reinforcement Learning model, but rather a supervised learning one based on the FICS game database of players with high ELO. Basically, I will train 2 separate models, one for white and one for black. Data for the white NN is taken from games where white wins, black NN takes black wins, drawn games are used for both, so that white moves in white winning games are considered "good", and vice versa. Is this a reasonable approach?

I don't know how to play Go at all, but the paper wrote:

History features Xt, Yt are necessary, because Go is not fully
observable solely from the current stones, as repetitions are
forbidden

For chess, I'm unable find any mention about it in the paper other than:

Unless otherwise specified, the training and search algorithm and
parameters are identical to AlphaGo Zero (29).

The training process was identical, but the sentence made no mention about the input features.
If you study the papers more carefully, the input features for Go is:
st = [Xt, Yt, Xt−1, Yt−1,..., Xt−7, Yt−7, C]

It's a representation only for Go, not chess. The input features for chess outlined in the paper covers 50-move rules and repetitions already, so there isn't any need for time steps in the input layer.
Google didn't use timesteps for chess, but only for Go.

Also, the architecture that I'm trying to build is not a Reinforcement
Learning model, but rather a supervised learning one based on the FICS
game database of players with high ELO. Basically, I will train 2
separate models, one for white and one for black. Data for the white
NN is taken from games where white wins, black NN takes black wins,
drawn games are used for both, so that white moves in white winning
games are considered "good", and vice versa. Is this a reasonable
approach?

Supervised learning is ok. It doesn't make sense to me for an ensemble of two models here. Why not just model it as a probability from 0 to 1?
EDIT:
You actually do need the entire game history in chess, for 50-moves and repetitions.


Time ran out against bare king If player A, who has a bare king, plays against player B who has around 9 pieces left on the board, and player B timer runs out (let's say player A's timer has 3 seconds remaining), who wins the match? Theoretically speaking, player A has no way to win the game but by player B's timer running out.

It's a draw.  FIDE rule 6.9 states (emphasis mine):

  Except where one of Articles 5.1.1, 5.1.2, 5.2.1, 5.2.2, 5.2.3 applies, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves.

Since the player with the bare king cannot checkmate the opponent by any legal sequence of moves, the game is drawn if his opponent runs out of time.