Rating calculations for Anand-Carlsen world championship I have some interesting questions that have to do with the rating changes and calculations for the Anand-Carlsen world championship.

First, some preliminary information:

Carlsen's live rating: 2870, Anand's live rating: 2775

If Carlsen wins a game, he gains 3.7 points; draw -1.3 points, loss -6.3 points.

If Anand wins a game, he gains 6.3 points; draw 1.3 points, loss -3.7 points.

The match will be 12 games, with the winner being the first to 6 points. Therefore, the number of standard rated games in the match can vary based on all the ordered possibilities of wins, draws, and losses.

My questions are:

1. What are the possibilities for Carlsen to cross 2900 in live rating?

2. What are the possibilities for Anand to cross 2800 in live rating?

3. What are the upper and lower bounds for Carlsen's rating in the match, given the stipulations?

4. What are the upper and lower bounds for Anand's rating in the match, given the stipulations?

Thanks!

First, note that the final ratings depend entirely on the score of the match, not on the particular games. For example, if they each win a game, their ratings will change by the same amount as if they draw both games. This may seem like a coincidence but it's just a consequence of the way that FIDE ratings work.

Here is the entire table of possible results. The columns are Anand's match score, Carlsen's match score, Anand's post-match rating, and Carlsen's post-match rating. The results are sorted by post-match rating.

  A   C  A_rat  C_rat
0.0 7.0 2749.1 2895.9
0.5 6.5 2754.1 2890.9
1.0 7.0 2755.4 2889.6
1.5 6.5 2760.4 2884.6
2.0 7.0 2761.7 2883.3
2.5 6.5 2766.7 2878.3
3.0 7.0 2768.0 2877.0
3.5 6.5 2773.0 2872.0
4.0 7.0 2774.3 2870.7
4.5 6.5 2779.3 2865.7
5.0 7.0 2780.6 2864.4
5.5 6.5 2785.6 2859.4
6.0 6.0 2790.6 2854.4
6.5 5.5 2795.6 2849.4
6.5 4.5 2799.3 2845.7
7.0 5.0 2800.6 2844.4
6.5 3.5 2803.0 2842.0
7.0 4.0 2804.3 2840.7
6.5 2.5 2806.7 2838.3
7.0 3.0 2808.0 2837.0
6.5 1.5 2810.4 2834.6
7.0 2.0 2811.7 2833.3
6.5 0.5 2814.1 2830.9
7.0 1.0 2815.4 2829.6
7.0 0.0 2819.1 2825.9

Therefor the answers to your questions are

None.
He needs to win the match with 7 points, or with 6.5 points with Carlsen scoring at most 3.5.
2895.9, 2825.9.
2819.1, 2749.1.


Are the GUIs of ChessBase chess programs the same? ChessBase (the company) has several chess analysis programs available: Fritz, Komodo Chess, Houdini Pro, Deep Junior and Deep Rybka. Do all of these programs use one and the same graphical user interface?

From the question Confused about ChessBase, the answer by @Apasserby sums the GUIs up nicely:

  Deep Fritz 14, Houdini 4, Komodo 9 and Rybka 4 all use the same Graphic User Interface (GUI).

So yes, ChessBase uses the same GUI.


What is the best opening for a beginner who wants few pieces on the board? I am a beginner and someone who likes less pieces on board. I don't like complexity and have weak point for knights. My rating is 950 rn and has touched 1010 at best.

So far I have used the Stone defence when playing with white and the King's Indian defence when playing with black.

Needless to say that defensive openings increase complexity.

What is best opening for black and white for me ?

I don't mind pieces exchanging. I just want less pieces on board that helps my mind process faster.

If your rating is around 1000, you should definitely abstain from the King's Indian for now. It is not a bad opening by any means, but it indeed is one of the more complex ones (requiring some sound strategic knowledge) .. too complex for your current skill level most likely, no offense.

That said, there is no "best" opening for beginners or anyone else, everyone has their own taste and has to find out themselves. You have to try different ones and make up your mind what works best for you. In general, focus more on learning the core principles of opening play (development of pieces, fight for the centre, etc.) rather than on memorizing exact variations. As long as your opponents don't play along (because they have no clue about the "correct" continuations), they are not of much use anyways.

You should definitely have a look at the category of the open and semi-open games (everything where White starts with 1.e4) instead of the closed ones you tried so far. Each opening has its own sharp or quiet lines (and your opponent has a word to say on that too!), but 1.e4 openings generally have a tendency to be more on the sharp side and are usually advised to be learned first by beginners because they are more educative at this level (less strategic and more tactical on average).

For the pinnacle of aggressive openings, there's the group of gambits. They do have some added complexity though because you have to be very accurate to maintain your lead in initiative (if your attack ever loses steam without getting the gambitted pawn back, you are in a bad spot) unlike the "mainstream" openings where a standard developing move usually doesn't lose on the spot (unless you fail to parry an urgent threat). Most of them are not "sound" enough to be played at GM level, but that does not have to concern you as you will rarely play against GMs. You have to do more preparation of variations than in other openings, so I suggest you don't start with gambits until after you tried the conventional openings for a bit.


What advantage does black gain from this move? Consider the following:

[FEN "r3q1k1/p2p1p1p/b1p2QpB/8/8/2r5/P4PPP/R5K1 b - - 0 1"]

Why is black's next move Qf8? White just follows with Bf8.

There is no good way to stop Qg7 mate. Black has to give up their queen.


What does it mean when engine position scores change when following the "best" move I'm particularly thinking of Stockfish here, since that is the one I use most, but it seems to happen with other engines.

Sometimes you have a position and the recommended move for white might be +1.7 say.  So you make the move and then for black the best move is suggested as being +0.6.

Is this because:

A)
The engine is not perfect, so if it can search 19 moves ahead, then after the move it can search one ply further into the game, and that reveals something that dramatically changes the score.  If so, what does this tell us about the position?

Or

B)
Does the engine take into account the possibility that the opponent won't play optimally.  E.g. does the engine assign any value to traps that are avoidable.  For example, Given a choice between going directly to a position, or transposing to that position via offering a trap you should clearly try the trap first.  Would the engine agree?  Is the score only reflecting the "best" line, or some average of possible lines?

I assume you used Stockfish with a GUI because the sign of the score would have been different if you didn't.

First of all, Stockfish is well known for its instability. The strongest chess engine isn't the best engine for analysis. This is like your local chess instructor might be a better coach than Kasparov for you.

A is obviously correct. Furthermore, the search algorithm could change as the hash-table gets filled up. The more that the engine "knows" about a particular position, the better it can analyse for the next position.


Chessbase 13 How to install UCI Engine when menu item is missing? I have the latest version of Chessbase 13, I have bought a license and activated it online.  For some reason, when I open a new board and go to the Home tab I do not have the menu item Create UIC Engine button.

As you see I have the choices Default Kibitzer, Add Kibitzer and Remove Kibitzer, but no additional choices while the image in the manual shows there is a small button below Remove Kibitzer that opens additional choices.

Have anyone else experienced this?  I have emailed Chessbase support, but they have not seen this before.

At the end of the line Remove Kibitzer, there is "UCI" written in red.  Click on that.


The games AlphaZero lost AlphaZero lost 6 games to Stockfish in a 1000-game match from the starting position, at least one of which was with the white pieces: A game A0 lost with white. For some reason, these games haven't received much media attention. Does this mean AlphaZero hasn't solved the game of chess yet? So, there is still scope for improvement? The media's report that AlphaZero is the perfect chess-playing machine is false.

AlphaZero hasn't solved chess, and it won't until it can find a strategy that results in the same outcome of the game given perfect play from both sides. According to Wikipedia:

  A solved game is a game whose outcome (win, lose or draw) can be correctly predicted from any position, assuming that both players play perfectly.

Since AlphaZero has lost games to Stockfish with both colours, we can assure it didn't solve the game. AlphaZero plays itself in training games. Had it solved the game, all these AlphaZero vs AlphaZero games will end up in one same result: either a win for white, a win for black or a draw.


Is the open Catalan a gambit? I have been looking at the open variation of the Catalan game, where White seems not to extremely worry about conceding the pawn with 4...dxc4, going for calm development instead. One notorious example is the below game where Black eventually gives back the material playing 9...b5 without (apparent) preparation; however, I do not see why this is necessary and the questions is whether the underlying idea for White behind this opening is to just gambit without really looking at any way of taking back the c4 pawn unless re-offered.

    [fen ""]
    [Event "WCC Match 2006"]
[Site "Elista RUS"]
[Date "2006.09.23"]
[EventDate "?"]
[Round "1"]
[Result "1-0"]
[White "Vladimir Kramnik"]
[Black "Veselin Topalov"]
[ECO "E04"]
[WhiteElo "2743"]
[BlackElo "2813"]
[PlyCount "149"]

    1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.g3 dxc4 5.Bg2 Bb4+ 6.Bd2 a5 7.Qc2 Bxd2+ 8.Qxd2 c6 9.a4 b5 10.axb5 cxb5 11.Qg5 O-O 12.Qxb5 Ba6

Another example is this other below game where again Black gives back the pawn after quite a few moves although it seems it could have defended and kept it, had it wanted to, preparing ...b5 after proper set up and development. I have purposely chosen to display games by Kramnik as he is a major player of the Catalan games and I assume his continuations in these positions are theoretically correct (hence it all boils down to what Black chooses).

[fen ""]
[Event "Corus"]
[Site "Wijk aan Zee NED"]
[Date "2007.01.21"]
[Round "8"]
[White "Vladimir Kramnik"]
[Black "Magnus Carlsen"]
[Result "1/2-1/2"]
[ECO "E04"]
[WhiteElo "2766"]
[BlackElo "2690"]
[TimeControl ""]
[Time ""]
[PlyCount "55"]
[EventDate "2007.01.13"]
[Annotator ""]

1. Nf3 Nf6 2. c4 e6 3. g3 d5 4. d4 dxc4 5. Bg2 a6 6. O-O Nc6 7. e3 Bd7 8. Nc3 Nd5 9. Nd2 Nb6 10. Qe2 Na5 11. Nde4 Be7 12. Nc5 Bc6 13. Bxc6+ Nxc6 14. Nxb7 Qc8 15. Nc5 O-O 16. N5a4 Nb4 17. Bd2 Rd8 18. a3 Nc6 19. Rac1 Rb8 20. Rfd1 e5 21.Nxb6 cxb6 22. Qxc4 exd4 23. Ne4 dxe3 24. Bxe3 Rxd1+ 25. Rxd1 Qb7 26. Rc1 Ne5 27. Qc7 f6

Does White play a gambit in the open Catalan or is the c4 pawn doomed to be taken back necessarily, at some point in the game?

Generally it seems to me if you want to keep the pawn on c4 with b5, white can play a4 which is cumbersome for black as protecting the pawn on b5 with c6 or a6 runs into pins on the a file or the h1-a8 diagonal. Even if you did manage this setup with pawns on a6, b5, c6 and c4 and maybe the bishop on b7 (or moving the rook out of the pins), black's light-squared bishop is very passive and moving any of these four pawns will create weaknesses or lose a pawn.

So yes, you could call it a gambit I guess.


Can I get by without a book for learning my opening repertoire (aside from the Sicilian Najdorf and KID)? My opening repertoire is currently consisting of:

White:

1.e4

Open Sicilian (5.Bg5 versus Najdorf, Yugoslav Attack versus Dragon)
Versus 1...e5, Scotch Gambit
Versus 1...e6, Tarrasch Variation: Korchnoi Gambit
Versus 1...c6, Panov-Botvinik Attack (don't know much here)

As Black:

Versus 1.e4, Sicilian Defence
Versus Anything Else, King's Indian Defence Setup

I have "Playing the King's Indian Defence" by Everyman Chess which I am currently studying back-to-back, and am planning to do the same with some book (not sure which one to get) on the Najdorf just because obviously, these openings are just so complex and have so many critical lines.

For the rest of the openings (Scotch Gambit, Korchnoi Gambit, Panov-Botvinik Attack, various Open Sicilian Lines), can I get by without a book and just research and learn thes line I want to play?

I am in the 1400's USCF.

At the USCF 1400-1500 level, the amount of reading you are planning on doing is already far too much. When you play people at your level they'll leave book pretty early; when you play people 400 points higher they'll beat you whether or not you have 12 moves memorized. The theory simply isn't going to matter for the vast majority of your games. Save the detailed reading and memorization until you get closer to 1800 at least. For now just play what you like, and after your game look things up in a database or a nice survey book like Fundamental Chess Openings (and if you want to know the ideas behind various openings, FCO is a fine place to start). Take the time you would have spent studying openings and use it to study tactics and endgames.

Of course, if you get lots of enjoyment from reading opening manuals cover to cover, I don't want to stop you. But it's not an efficient way to improve your results (especially at your current level), and you certainly don't need to do it for every opening you think you might encounter.


What are the worst blunders ever committed in a world championship match (final)? As title above, what are a few of the worst blunders ever committed in a World Chess Championship Match?

By far, the biggest blunder in all world championship is absolutely 32.Bb4?? played by Chigorin in the 1892 match. He threw away the win and the match, landed himself to mate in 2.

https://en.wikipedia.org/wiki/World_Chess_Championship_1892
A piece up, Chigorin should have won after 32. Rxb7 (32...Rxd5? 33. Nf4 forks the black rooks).[1] Instead the game and match ended suddenly when Chigorin blundered with 32. Bb4?? Rxh2+ White resigns, as Black will mate on the next move.[1][3]


Book recommendation for chess engine building This might be too broad a question, but can anyone recommend specific books that deal with chess engines, including hard-coded ones such as Stockfish, Komodo, and other ones also based on neural networks and reinforcement learning? I want to get a broad overview of the logic behind chess engines, and maybe experiment in building one myself. For starters, is there anywhere I can refer to understand the Stockfish source code for example, and Alpha Zero respectively?

To my knowledge there is no book on chess engine programming because there is no market.
People study the source code simply by reading it. If you have any question, please join Stockfish/LC0 discord. It worked well for me, I just ask online anything I don't understand.
I would suggest the following on learning. Many more I may have missed.

https://www.chessprogramming.org/Main_Page
https://www.talkchess.com
https://lib.vsu.by/jspui/handle/123456789/20821 (Deep learning for chess ai)
Stockfish/LC0 discoards
https://groups.google.com/forum/#!forum/fishcooking


Does Boris Gelfand share his surname with a chess piece? Boris Gelfand was just narrowly edged out by Anand in their match's rapid tiebreaks, and I thought I'd ask an oddball question related to him.

The bishop chess piece is known by several different sorts of names in different languages. For instance, while in Icelandic it is referred to as a "biskup," which is their equivalent of bishop, in German, Danish, Norwegian, Swedish and Finnish the piece is called by those languages' respective equivalents of "runner." In Romanian it is termed a "nebun," or crazy person, and in French it is called a "fou," or fool/jester. (See this Wikipedia entry for more detail.)

Some languages, such as Russian and Turkish, use their terms for "elephant" to refer to the bishop piece, which harkens back to the Indian roots of chess in shatranj and chaturanga. Now as it turns out, "gelfand" is the Yiddish word for an elephant,
and this got me wondering how the bishop is named in Yiddish. Despite my best googling,
which turned up useful references like this one, I surprisingly found no answer
to this question, and I don't know any Yiddish-speaking chess players. And since Yiddish
is a fusion of Hebrew, German, Slavic languages and Romance languages, it's tough to guess which sort of bishop name it would end up with.

So, getting to the point, can anyone tell me:

  Is the bishop referred to as a "gelfand" in Yiddish?

Well, just when I was writing the question up, I finally found the answer -- no -- so I am answering my own question. Way down at the bottom of this web page, it gives the Yiddish name for the bishop (once transcribed from the Hebrew alphabet) as "der Loyfer," which is like the German name "der Läufer." So, assuming this is a reliable source (and it's the only one I could find), the Yiddish bishop is a runner, not an elephant. It's just not Gelfand's day I guess.


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

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

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

[FEN ""]

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

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

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

Anyways, what I suggest you do is to:

1) Keep playing every day. Experience is king.

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

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

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

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

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

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

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

Good Luck and Good Chess!


Why does NCM show no progress for Stockfish when each new version has to beat the previous version? NCM plays each Stockfish dev build 20,000 times against Stockfish 7. This yields an approximate Elo difference and establishes confidence in the strength of the dev builds. As of time of writing, one can see from the plot that Stockfish's strength hasn't really budged for a month: version 20190324-1637 had a performance of +217.95 +/- 3.73 elo relative to Stockfish 7, while the latest version 20190420-0634 is +221.52 +/- 3.79 elo. The gap is within the error bars.

(It's possible that this is sort of the expected performance increase in a month's time, but the latest version's results appear to be anomalously high. For example the next-latest version, 20190419-1533, is +218.61 +/- 3.77 and almost indistinguishable from the 20190324-1637 version.)

The weird thing is, for each version of Stockfish to be promoted to the "main version", it has to beat the previous version. All these new versions of Stockfish (that aren't non-functional changes) have to do this. If we look at the catalogue of Stockfish patches, we see patches such as:

  Author: protonspring
  Date: Tue Apr 16 23:10:53 2019 +0200
  Timestamp: 1555449053

  Move pawnsOnSquares to Position (#2100)

  We can remove the values in Pawns if we just use the piece arrays in Position. This reduces the size of a pawn entry. This simplification passed individually, and in concert with ps_passedcount100 (removes passedCount storage in pawns.).

  STC
  LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
  Total: 19957 W: 4529 L: 4404 D: 11024 Elo +2.18
  http://tests.stockfishchess.org/tests/view/5cb3c2d00ebc5925cf016f0d

  Combo STC
  LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
  Total: 17368 W: 3925 L: 3795 D: 9648 Elo +2.60
  http://tests.stockfishchess.org/tests/view/5cb3d3510ebc5925cf01709a

In other words this version of Stockfish defeated the previous one by ~2 elo. Why isn't this ~2 elo showing up in the NCM data? I know elo isn't transitive (i.e. if engine A beats engine B by 50 elo and engine B beats engine C by 50 elo, it doesn't mean engine A beats engine C by 100 elo), but this is just one patch, and there were plenty of elo-gaining patches that passed Fishtest. For NCM to show no progress for months, in spite of all these patches, doesn't make sense to me.

Fishtest tests proposed changes to Stockfish's code with SPRT to determine if they should be accepted. Broadly speaking, there are two types of changes which are tested in this way (non-functional changes do not go through Fishtest): simplifications, and changes which intend to gain strength - elo changes.

The crucial difference here is that simplifications (like the one referenced in the question) are tested for no regression, whereas elo changes are tested for an improvement: SPRT bounds of [0.5, 4.5] are used for elo changes and bounds of [-3, 1] are used for simplifications.

The vast majority of changes to Stockfish recently have been simplifications, and as such they are not expected to increase strength.

For example, the patch in the question is a simplification, and was tested with SPRT bounds [-3.00, 1.00]. The fact that it passed tells us that there is a 95% chance that the change does not lose 3 elo. If the test failed, we would know that there is a 95% chance that the change does not gain 1 elo.

We can't say anything more precise than this, because SPRT stops immediately as soon as there is enough evidence to accept either hypothesis and doesn't attempt to measure the elo change more precisely. Although an elo difference of +2.18 is quoted at STC, all we know is that the lower error bound on the elo gain is >= -3.00.

There is insufficient evidence to say that the change produced an actual elo gain of +2.18, and thus claiming that this simplification gains 2 elo would be misleading.

The small number of elo gaining changes is what results in Stockfish's slow progress at the moment.


How are humans good at chess? It is estimated that the total number of legal positions in chess is somewhere between 10^40 and 10^50. This is of course an enormous number. Computers today with reasonably good chess software can sometimes look 20 moves ahead to find the best continuation.

But (most) humans are incapable of such calculations. After each move, it is practically impossible to compute all the ramifications and variations. Therefore a move made by a human being is expected to be a very poor move indeed.

But this is not the case: looking at GMs games, those people are able to find the ''best'' moves recommended by top engines such as Stockfish, even though they obviously are not calculating billions of combinations per minute.

So what makes humans good at chess, if they are unable to see into the vast space of future variations? When looking at what GMs do better than amateurs, what I usually find is better ''intuition'' or ''feeling for the position''. But these can't be quantified. And GMs are obviously not psychic. So how can they find the best move most of the time? Chess masters often insist that they are not following an internal ''algorithm''. So what on Earth are they following?

How can humans be so good at chess?

Herbert Simon touched on this question. He received the Turing Award in 1975 and the Nobel Prize in Economics in 1978. His primary research interest was decision-making and is best known for the theories of "bounded rationality" and "satisficing".

Satisficing is a decision-making strategy or cognitive heuristic that entails searching through the available alternatives until an acceptability threshold is met. Simon used satisficing to explain the behavior of decision makers under circumstances in which an optimal solution cannot be determined.

In his paper Theories of Bounded Rationality (1972), Simon used "the game of chess as a microcosm that mirrors interesting properties of decision-making situations in the real world." Here are some useful quotes.

  On the average, at any given position in a game of chess, there are
  about 30 legal moves-in round numbers, for a move and its replies, an
  average of about 10^3 continuations. Forty moves would be a not
  unreasonable estimate of the average length of a game. Then there
  would be perhaps 10^120 possible games of chess. Obviously the exact
  number does not matter: a number like 10^40 would be less
  spectacular, but quite large enough to support the conclusions of the
  present argument.

  Chess players do not consider all possible strategies and pick the
  best, but generate and examine a rather small number, making a choice
  as soon as they discover one that they regard as satisfactory.

The limits of rationality in chess.

  (...) three limits on perfect rationality were listed: uncertainty
  about the consequences that would follow from each alternative,
  incomplete information about the set of alternatives, and complexity
  preventing the necessary computations from being carried out. Chess
  illustrates how, in real world problem-solving situations, these three
  categories tend to merge.

Satisficing and optimizing.

  The terms satisficing and optimizing (...) are labels for two broad
  approaches to rational behavior in situations where complexity and
  uncertainty make global rationality impossible. In these situations,
  optimization becomes approximate optimization - the description of the
  real-world situation is radically simplified until reduced to a degree
  of complication that the decision maker can handle. Satisficing
  approaches seek this simplification in a somewhat different direction,
  retaining more of the detail of the real-world situation, but settling
  for a satisfactory, rather than an approximate-best, decision. One
  cannot predict in general which approach will lead to the better
  decisions as measured by their real-world consequences. In chess at
  least, good players have clearly found satisficing more useful than
  approximating-and optimizing


How can I save this game? I was playing a blitz game and the time control was 2m+1s. The end game was KQ vs KR and I (with KQ) lost on time as it took roughly 2 seconds for me to make a move. I would like to learn a lesson: in this endgame (KQ vs KR), can I force a draw if I am running out of time?

I can try three-fold repetition, but my opponent will not cooperate.
I can try exchanging, but my opponent will not block my check with their rook.

can I force a draw if I am running out of time?

Of course! Just swap the queen for the rook.

There are two basic possibilities.

He keeps the king and rook very close (normal best practice when trying to draw this difficult endgame). In that case every time you threaten the rook with your queen he must move the rook and keep it close to the king. It should be easy to then skewer the king against the rook with a check or pin the rook against the king. This probably won't happen immediately but if you know what you are aiming for your opponent will find it very difficult to avoid for long, particularly since he also needs to avoid losing.
He keeps the rook and king well separated. This is fatal. The rook quickly falls to a fork.


Render a chessboard from a PGN file I’d like to render a 2D chessboard image and save it after the last move as a PNG or JPEG from a given PGN file on a Linux console. How can I do this?

I have a PGN file and I want to get a screenshot of the board.

Seems to be a simple task but I can’t find a solution for it which is scriptable on the Linux console.

P.S. The wording "simple task" seems to be annoying for some readers here. Being not a native speaker I have a hard time to understand this nuance but I by no mean want to step on anybody's feet. Coming from a Linux console background I have the feeling that this should be doable on the console with ease. But that I haven't found the tool to do it.

You can use the SVG rendering functionalities of python-chess. This will allow you to create a SVG-formatted visualisation of any board position loaded using python-chess.
FEN to SVG
For example, given a FEN as input (say we save our python script as boardtosvg.py)
Using python3 and the python-chess library version 0.30.1
import chess
import chess.svg
import sys

arguments = sys.argv
fen = str(arguments[1])

board = chess.Board(fen)
boardsvg = chess.svg.board(board=board)
f = open("BoardVisualisedFromFEN.SVG", "w")
f.write(boardsvg)
f.close()

Example, FEN: 'rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1'

Command to run your script from the terminal:
python boardtosvg.py 'rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1'

Saved file (in case you cannot open SVGs, you can at least use a browser such as chrome to view the file):

Position from a PGN to SVG
Similarly, if the input is a PGN file, then here's how you'd for istance save the SVG of the last position of the game (you can extend this to saving the position at any move):
import chess
import chess.svg
import chess.pgn
import sys

arguments = sys.argv
pgnfilename = str(arguments[1])

#Read pgn file:
with open(pgnfilename) as f:
    game = chess.pgn.read_game(f)
#Go to the end of the game and create a chess.Board() from it:
game = game.end()
board = game.board()
boardsvg = chess.svg.board(board=board)
f = open("BoardVisualisedFromPGN.SVG", "w")
f.write(boardsvg)
f.close()

Example, PGN of Adams vs Kasparov 2005: adams_kasparov_2005.pgn
python boardtosvg.py 'adams_kasparov_2005.pgn'

Saved file:

Now all that is left to do is to convert the so-created SVG files to PNG, which you can also do in python, see the solutions in the link below:

Convert SVG to PNG in Python


Positional motifs and training websites/softwares/apps? Tactics have motifs like skewer, pin, fork, weak back rank etc which can be used to guide you towards candidate moves.

Are there similar positional motifs?

I think Silman's imbalances is close to what I'm asking for, but is a bit too higher level and not especially useful in generating candidate moves. His concept of dream position is something to target in 10+ moves, and I find it hard to implement in practice. (Yes, major piece ending with his backward pawn is good for me, but we have 4 minors to trade, what's the first move?)

I'm looking for something less blue-sky and can give guidance for the next 1-2 moves. Example: h4-h5 against king side fiachetto; c4 is more powerful when opponent puts B on d6 (usually with opposing pawns in d4,d5).

Of course, just as a pin does not always lead to winning a piece, these are ways to generate candidate moves and everything needs to be checked in a concrete position.

Also, are there any training software/website like chesstempo, but on positional puzzle? I tried chessimmo, but its positional puzzles are mostly opening moves (I only did the free ones though).

I found a very useful guide to thinking about both positional and tactical situations in an online course offered by VisualWize, who make chess visualization training software.  You can find it here.

You might find the portion of the course on positional evaluation helpful.

There are both sections of content and exercises to practice what you've learned. I have not tried their other training courses, which go into this material in more depth, but this course struck me as comprehensive and effective.

I admit to using an amalgam of different methods that I've learned from
multiple sources, but this is the closest I can find to a comprehensive system.

You can also try a variety of chess training apps offered by ChessOK on the PC, and Chess King on Android (and probably Apple) - these are the same people, in two different markets.  On Android, their "Strategy" app offers a limited number of theoretical topics for free, plus a corresponding set of problems that cover Development, Space, Attack on the King, Attack on the Queenside, and Defense/Counterattack.  For a small charge (less than $10), you can buy the rest of the course, including 13 more topics in areas like: weak squares, positional sacrifices, hanging pawns, improving your pieces, pawn structure, open files and diagonals, etc.

Andrew Soltis wrote a good book on choosing a strategic move (well, any move) called How to Choose a Chess Move, in which he offered a short course in "priyomes", which are short plans to be used in certain types of positions to accomplish a short-term objective.  Unfortunately, there is no catalog of priyomes anywhere, since there 10's of thousands of them (apparently), but you get a good introduction to the concept.  Also, Mauricio Flores Rios' book, Chess Structures discusses quite a few openings, their tabiyas, and the types of plans each offers for both sides. That makes it a kind of catalog for priyomes for the openings.  These aren't software, but you can't always have everything...

Arthur Van De Oudeweetering has written an interesting book on 40 less well-known (but actually fairly frequently-occurring) priyomes that he has identified, which is called Improve Your Chess Pattern Recognition.  I'm working my way through that book, and adding the patterns to my pattern store, because they're surprisingly common (and effective).  He also does something I don't see often in chess training materials: he complements the normal "Do's" with some "Don'ts", pointing out some of the kinds of anomalies in the position that could render the pattern ineffective or even dangerous.

He has now published a sequel, called Train Your Chess Pattern Recognition.  I haven't seen this one, but I'd be surprised if it doesn't live up to the original. BTW: An Amazon reviewer has warned against buying the Kindle version of the 2nd book because the figurine characters don't render properly; the first book's Kindle edition is fine.


Can I promote to a queen twice? I am confused about pawn promotion. If I promote two different pawns, can I promote them both to a queen?

Even all 8 of them, if you manage to get them to the opposite back rank. Let's look at the relevant part in the Laws of Chess:

  3.7e When a player, having the move, plays a pawn to the rank furthest from its starting position, he must exchange that pawn as part of the same move for a new queen, rook, bishop or knight of the same colour on the intended square of arrival.
  This is called the square of ‘promotion’. The player's choice is not restricted to pieces that have been captured previously. This exchange of a pawn for another piece is called promotion, and the effect of the new piece is immediate.

The bold emphasis is my own and probably the important part for resolving your confusion.


Why does the FIDE ID change sometimes? I noticed that FIDE ID (unique ID used on FIDE rating lists) changes for some players. E.g. Igor Khenkin had 3 different IDs (4659600, 4135814 and 2802350).

Sometimes (like for Khenkin) ID changes when player switches federations, but most players change federation and their FIDE ID stays the same.
Also, some players (e.g. Yimam Abera) have their ID changed while everything else stays unchanged.

Worse, it seems old ID can be used by different player (e.g. Shirov's 11600012 was later reused by Olegs Marutkins).

Are there any rules here? Is there a way to decide which FIDE IDs belong to the same person?

Actually it is worse than you say. Igor Khenkin has had a total of 5 FINs (FIDE ID numbers)! He has had the following FINs -

62480 (January 1990, FINs first introduced)

4101430 (July 1990, oops! What happens if we have more than 99,999 FIDE rated players? Make FINs longer. Everybody's FIN changes)

2802350 (July 1993, Khenkin changes federation from RUS to ISR)

4135814 (January 1998, Khenkin changes back from ISR to RUS. Note he doesn't get his old number back)

4659600 (January 1999, still not happy he changes federation from RUS to GER)

Note also that the situation with Shirov's FIN - 11600012 - is also worse than you suggest!

In the January 1990 list when FINs were first introduced the player S. S. Alsharfi from South Yemen was given 71366. Six month later when the longer FINs were introduced his FIN was changed to 11600012. By the time of the January 1991 list South Yemen and North Yemen had merged into Yemen. This meant a new federation and so his FIN was changed again to 9400010 leaving 11600012 free.

Meanwhile Alexei Shirov's FIN history looks like this -

82074 (January 1990 list - short FINs, he is playing for USSR)

4100220 (July 1990 - long FINs)

11600012 (January 1992, FIDE recognizes the breakup of the USSR and Shirov becomes a Latvian player, with a new FIN. Except it is actually an old FIN previously held by the South Yemeni player)

2209390 (January 1995, Shirov moves from Latvia to Spain and gets a new FIN leaving 11600012 "vacant" for use by a Latvian player)

In October 2008 Latvian player Olegs Marutkins gets Shirov's old number.

The current FIDE rating website goes back to 2001 and doesn't seem to have knowledge of FIDE ratings and FIDE rated players before then. Players who were inactive then and who have remained inactive do not appear. One example would be the current British chess problem solving champion, English player Ian Robert Watson. He was active from January 1978 through January 1984 with a rating varying between 2200 and 2215. He played before the era of FINs and doesn't appear in FIDE's records. He still plays local club chess and has an ECF rating of 198 which is roughly equivalent to 2200.

However since 2001 the FIN changes with federation seem to have stopped. For instance Fabiano Caruana had the FIN 2020009 in 2004 when he played for the USA. When he changed federation in 2005 to Italy he retained the same FIN and again when he changed back to USA in 2015.

OlimpBase is a good source of information. The FIDE rating website only has information from 2001 while OlimpBase has records going all the way back to 1967 when unofficial rating lists were first produced.

FIDE first gave out FINs in January 1990 but they were only 5 digits long. Somebody worked out that this didn't give much room for expansion and so when the new list came out 6 months later everybody got a new, much longer FIN.

Note that OlimpBase has collected this early rating information which can be downloaded here. They also have information for the period 2002 through 2009 here. This was what I used as the source for the information above.


Is this K+4P vs KB+P endgame drawn? Is that position always a draw? I've tried to play it few times and I always end with lone bishop or a stalemate

8/3k3/p7/2Pb4/PP6/2KP4/8/8 w KQkq - 0 1

You cannot get a definitive answer, but in all likelihood, 99.99% it is a draw no matter who is to move (I am the type of person, who never says I am positive unless there is 100% proof, and that is impossible here, however likely).

The overwhelming factor in this position is that the black bishop does not control the a1 square, so even if white had no pawns, it would be a draw. It is clear that white can also never break the blockade either if black just plants his king on c6. It would remind me of an opposite color bishop blockade, but white has no bishop. Just Kc6, and Bd5-h1 with an easy draw.

The only reasonable exception would be if somehow white played a5, and later was zugzwanged into having to play b5 (like eventual stalemating the king on a1, forcing b5. That said, just avoid a5 (white can actually play b5 right now if on the move to avoid that issue).

It seems like a pretty easy draw either way to this long-time Master.

P.S. My Stockfish at a depth of 48 still reads 0.00


Read chessbase files (.cbv) on ios? Is there any ios app that can read .cbv files?

If not, how can I convert them to .pgn? I tried to follow this post, but the output is "parse error" to chess viewer (developed by everyman chess).

Any suggestion?

To my knowledge there is no such iOS app. Sorry.

Try the Chessbase Fritz to do the conversion.


How can I migrate my openings from Chess Position Trainer to another database when the pgn too large to import? I have used Chess Position Trainer for years.  I now only play "postal" chess and no longer memorize openings.  Also chess position trainer is the only application I have the requires windows and I would like to stop using windows.

Some of my openings seem to be too large to import.  I have tried importing into chess tempo, ChessBase, and a local HIARCS chess explorer and they all error on import for large openings.

Chess Position Trainer supports exporting as a single PGN or a game per variation.  exporting as a game per variation scales better but still does not work for my largest openings such as King's Indian as black.

How can I migrate my openings from Chess Position Trainer to another database?

I am using Chess Position Trainer 5.04

My preference was to use Chess Tempo but would be happy for suggestions of other chess database software to try, either browser based or local for my mac.

You can export subsets of your tree of moves or export each variation as an individual game within the same file. Acording to the manual: "You can export an opening or topic as PGN file which then can be imported by many other chess programs. Several options let you configure the export to your preferences. The  most importantone might be the option to export as “One Game” or “One  Game  per  Variation” (the latter is only available for openings).


Free chess computer game I am a chess novice.

Can someone suggest a good, free chess computer game that I can use to start to learn chess by playing against the computer?  Maybe with some different difficult levels...

It depends on which operating system you are running.  If you are running a Linux OS, there are many, many options for you to choose from.  One of the more-popular options is glChess.

It has a few features that make it a good game to learn on:

highlighting possible moves when selecting a piece
ability to turn board numbering on/off
keeps a history of moves
has a mechanism that allows you to iterate through  the move history to see the development of the board.
allows configuration of computer players using several existing engines.

Once you get a little more advanced, a good one is XBoard.  While designed to run on Linux, there is also a Windows port called WinBoard.

While it might not look as pretty as other games, it has plenty of options:

Like glChess, can be interfaced with several engines.
Can play over the internet.
Has an interface for Chess via email.
Maintains your games in SAN notation.

While very feature-rich, XBoard is probably a good one to get once you have a few games under your belt.

If you are on a Windows OS (Windows 7 or Vista) Chess Titans is good for starting-out, too.  While probably scoffed at by many on this forum, the advantages of Chess Titans are:

Several levels of play (1 through 10) of increasing difficulty.
If you have Windows 7 or Vista, you probably already have it installed.
Aesthetically-pleasing (if you care about that).


Bughouse chess tournament pairing software? Does anyone know of a (free) program which could be used to organize a bughouse chess tournament?

Where in each round the partner you have would change. (With the basic idea to put a good and 'less good' player in the same team.) The good player would be defined as the one with the most bughouse team wins.

Or how should I try to manage such a tournament? Any ideas?

There is no pairing program which can do what you want. No program exists to change the partners every round according to the previous results. Pairing programs also try and avoid pairing players or teams which have played before.

Exactly how the partners would vary and how you would decide who had played whom is not clearly defined in your system. Your idea needs more work.


Can playing too much chess make you see everything as chess moves? According to this answer, some schizophrenics who compulsively play chess a whole lot see everything as chess moves. I looked for an alternate source of that information through a Google search and never found one.
Also, I used to play The Legend of Zelda Breath of the Wild a whole lot, maybe many hours a day. After enough time of continuously playing it so often, I felt like I was seeing the real world as part of the Breath of the Wild game. (Of course, playing the game isn't the exact same experience as it would have been if I were out in the Breath of the Wild map in real life.) I had been playing breath of the wild so much and so continuously that when I was exploring the real world, it sort of felt like I was exploring an area that looked like that in the game. After I did as much as I felt like doing in that game, I never got around to playing it again for over a year. I no longer see the real world that way anymore.
Could the experience be something like that for people who play chess so many hours a day?

Quite possible- this would be a special case of the Tetris Effect, as would what you described with your experience with Breath of the Wild.
Anecdotally, someone I knew once played a lot of chess online and experienced similar effects. About 9 hours per day were spent on chess, roughly equally divided between play and study. This person experienced such effects as:
They sent a one-word message and became anxious that they blundered since it was "hanging"
Noticing two socks were on the floor and immediately thinking "good, they're connected"
They also dreamed about chess, which is almost universal among players that play a lot of chess.
I wouldn't expect this happening to you - 9 hours is a lot, and anecdotally, I've spent a lot of time on chess myself and have yet to see any such effects beyond just dreaming about it. They also mentioned that they had tetris effect tendencies.


Beginner Openings/Defenses to learn What are good openings/defenses to study for both black and white for beginners. I've messed around with the sicilian defense and it is not bad, there's just so many variations and different types of defenses/openings its overwhelming. I understand the only way to learn is to play one for a little while. Are there any sites with virtual chess boards that show step by step examples of some of the popular styles. It's not easy to learn when all you get e4, e5 nf3 etc. Are there any viable openings for white other than d4/e4, these seem overused and very cliche

In my opinion this is a pretty hard question to answer, because there is no single correct answer to it.

The choice of opening repertoire for a player should be determined by his play style, e.g. do you prefer to be aggressive always on the offense or are you more of a tactical player, looking for strategic weaknesses in your opponent's position, do you prefer closed over open positions, etc.

So my answer to your question would be to follow the basic principles of opening play:

control the center;
develop your minor pieces to their best squares;
get your king to safety;
do not move a single piece too often in the opening, unless there's a pretty good reason to do so;
do not bring your queen out too early.

From there on pick an opening that fits your play style and study the ideas behind it, not just memorize the moves, understand what each of them accomplishes.

  Are there any viable openings for white other than d4/e4, these seem
  overused and very cliche

These opening moves are most certainly not cliche. Although you might see these moves as the first move in almost every game there are lots of variations that follow. Therefore my recommendation for you would be to play an opening from the family of The Italian Game as White and maybe The French Defense as Black.

From my experience as an amateur I came to the conclusion that one shouldn't focus too much on openings. After you pick an opening that fits your style, focus on the endgame and various tactics and strategic ideas. This seems to be more efficient in the long run.

Good luck!


Why does black gain from this "center fork trick"? In the following position, Bc4 by white is evaluated as a bad move that can be punished by ...Nxe4.
Although I can see why it tactically works, I fail to see how the resulting position favors black. Do you have any insights about why it's better for black, and what are the plans that follow ...Nxe4?
[fen "rnbq1rk1/ppp1ppbp/3p1np1/8/2BPP3/2N2N1P/PPP2PP1/R1BQK2R b KQ - 1 0"]

1...Nxe4 2.Nxe4 (2.Bxf7+ Rxf7 3.Nxe4) d5 3.Bd3 dxe4 4.Bxe4

White is enjoying a space advantage in the center, but not anymore after ...Nxe4. It would be the "equivalent" of playing a ...d5 push, which unfortunately doesn't work in this position.
White can reply to 1...Nxe4 with either 2.Nxe4 d5 3.Bd3 dxe4 Bxe4, which would leave Black with an at least equal position, or with 2.Bxf7+ Rxf7 3.Nxe4 which would allow Black to start putting pressure on the center (let's think of moves like ...Nc6 and ...e5 for instance)


Is chess a game of skill or chance? To what extent? I want to know whether chess is a game of skill or game of chance, and how much is the degree of skill or chance in terms of percentage.

Edit (21 Feb 2014):

Please make sure that your answer includes credible references. To be sure that chess is a game of skill (or chance?).

If we remove the component of flawed, human players from the equation and consider just the game of chess itself as it is spelled out by the rules, then chess is purely a game of skill with no room for chance. That is, it is in principle possible for there to be a perfect chess player that plays optimally against every possible move sequence by an opponent, and that perfect player would never falter due to chance or luck. Such perfect players already exist at the level of chess positions with only a handful of pieces: endgame tablebases consist of all the information necessary for perfect play in those positions, and if you play from such a position against an opponent with access to those tablebases, chance can play no role in stopping them from getting their deserved result.

However, the problem of computing a tablebase for the starting position of chess, with its 32 pieces, is far, far from tractable. So while optimal play does exist for all positions in chess, nobody knows for sure what optimal play is for the vast, vast majority of positions. Looked at in that light, when two humans (or even strong chess engines) play a game against one another, something that can reasonably be viewed as chance (for one side at least) can definitely play a role, but for what I have in mind at least, the root cause of any outcome is still skill (or its temporary absence).

Here's an example of what I mean. In the recent Zurich Chess Challenge, Nakamura was playing a fine game against Carlsen, to the point where he had an overwhelming, winning advantage. At that point, it could safely be said that Carlsen "deserved" to lose.

[fen "4r1k1/1p3pPp/6q1/2pPpNP1/p1n1P3/P6Q/7R/K7 w KQkq - 0 1"]
[White "Nakamura, Hikaru"]
[Black "Carlsen, Magnus"]
[Event "Zurich Chess Challenge"]
[Result "0-1"]

1.d6? (1.Qf1!)

But Nakamura made a crucial mistake that let Carlsen off the hook, later followed by further poor play that even allowed Carlsen to win. If someone were to say, "Carlsen was lucky to win that day," I'd say there's truth to that. (Carlsen certainly deserves credit for defending in such a way that Nakamura could still go wrong, but even so, he was fortunate that Nakamura erred as he did.) But the luck from Carlsen's side originated from nothing more than a momentary lack of skill on Nakamura's part. Finding the right move was entirely within Nakamura's power, but he wasn't quite skillful enough to find it in that moment.

As in most human endeavors, there is some element of chance in the competitive results of chess games. But that luck for one side generally comes in the form of what kind of lack of skill one's opponent shows (and when).


I would like an iPad app for annotating my games I would like an app for annotating my games and/or replay others' games.  Do you have any suggestions?

Stockfish works well for this purpose; and it's free software.


Can Grandmasters beat computers when given time-odds? For eg., if a grandmaster is given 10:1 time odds, will he be able to beat a computer? For eg, if the GM is given 120 minutes for the entire game and the computer is given 12 minutes? If not 10:1 times odds, then please mention what time odds would be required for a GM to beat a computer.

Yes. A grandmaster or a team of grandmasters can hold a draw or win against an engine when given time odds.

I think that there is a minimum time control at which an engine can perform equally good or better than a grandmaster (without time odds). I guess this number is somewhere around 2 or 3 minutes for the whole game.

Let's say for simplicity that it is 5 minutes. So the engine needs 5 minutes for the whole game to perform at a decent level. Now, how many minutes does a grandmaster need to match an engine that has 5 minutes?

It depends. In the opening, the human player needs to be well prepared. Otherwise, it doesn't matter too much if the player has 5 or 50 minutes for the opening part. In the middlegame, my guess is that the player should avoid sharp positions and go for calm waters to reach an equal or slightly better endgame. Try to keep a healthy pawn structure and find long term advantages.

The endgame is where the player has a good chance of holding a draw or winning the game. In general, the more time for middlegame and endgame, the better. I would say that around 20 minutes for the opening, 40 minutes for the middlegame and 40 minutes for the endgame should give the human player a fair chance. That gives a 20:1 ratio (engine has 5 minutes).

This is a rough guess and it needs to be tested in practice. Such a test would be interesting! If the player has a chance to practice against the engine, then the player will of course be even better prepared for a match. I guess such a preparation is pretty normal for human versus machine matches.

My guess would be that the engine's strength grows faster per additional minute than the human strength per additional 20 minutes. When the engine has 15 or 20 minutes for the whole game, it might already be difficult for the human player to match its strength, despite having extra time. Yet, a team of grandmasters should cope pretty well (given time odds).


Why is the Ruy Lopez a sensible opening for white? As an amateur, I prefer the Scotch game as opposed to Ruy Lopez, since I feel that White loses tempo and Black seems to gain tempo with queenside counterplay in the main line.

 [title "Ruy Lopez"]
 [fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 {Bishop retreat at the expense of black gaining one queenside counterplay} b5 5. Bb3 {Another bishop retreat at the expense of black gaining a good queenside counterplay}

At the end of White's fifth move, it looks like Black is couple of tempo ahead and already has queenside counterplay going. Despite this, why is this one of (if not the most) celebrated openings? Can someone offer an explanation at the level of an amateur?

Sure black's a6-b5 come with tempo, but let's say at a very basic level, if you just compare pieces, structure and development progress, you can see that white is:

Ready to castle whereas black hasn't yet developed either kingside pieces, so at least 2 tempi away from castling. This translates into white having a safer king 1-2 tempi earlier, which means white has the upper-hand in launching some sort of attack or push.
White has developed two minor pieces that stand quite well: Knight on f3 attacks e5 and has the potential to coordinate on f7 with the bishop on b3 already eyeing black's kingside. In contrast, black has only developed a knight, one that stands defensively on c6 covering e5.
Besides the e4 pawn, white has nearly kept all pawn advancement options still on the table (therefore, can opt for various pawn structures still), whereas black has made 2 additional commitments that cannot be undone, which can on the one hand, prove to have been self-inducing weaknesses, and on the other hand, be hooks (targets) for white's pawn advancements on the queenside, e.g. an a4 push, to which black has to react immediately.

These ways of reasoning can be adopted to conceptually assess nearly any opening you see, at least at a basic level.

The point on pawn commitments cannot be emphasized enough, they're the most committal moves in the game (trades come close but at least in principle a piece can be brought back to life with a promotion, but pawns cannot! :P ). Even at the highest level, for instance take a look at any of Caruana's openings in the match so far, where roughly speaking, he intentionally favours lines where he can delay unnecessary pawn moves and keep most of his options open. Examples:

Game 2:

 [title "Game 2, move 13, only 3 central pawns moved, compare to white!"]
 [fen "r1br2k1/pp3ppp/2n1p3/q1bp4/2P2B2/P1P1PN2/2Q1BPPP/3R1RK1 b - - 0 13"]

Game 4:

 [title "Game 4, move 13, only 2 central pawns moved, compare to white!"]
 [fen "r1bqr1k1/ppp2ppp/3b4/4p3/1P6/2BP1BP1/P3PP1P/1R1Q1RK1 b - - 0 13"]

game 6:

 [title "Game 6, move 13, only 2 central pawns moved, compare to white!"]
 [fen "r1b1kb1r/pppn1ppp/3pn3/3N4/3P4/N1P2P2/PP4PP/R1B1KB1R b KQkq - 0 13"]

game 8:

 [title "Game 8, move 16, only 3 pawns moved, compare to black!"]
 [fen "1rbq1rk1/1p2b1pp/pN1p4/P2Pnp2/4p3/8/1PPBBPPP/R2Q1RK1 w - - 4 17"]

Anyhow I think the idea is clear now! It's important to add that in all these examples, the simple fact of having moved less pawns doesn't directly or necessarily translate into having a better position, chess is never that simple or linear. Partly, specially in this examples, it is a case of style and preference (and thus the adopted openings), but on the other hand it shows you the importance of diversity in pawn structures that can still be opted for as they translate into having more choices, abundantly clear even at the highest level.

I hope these ideas have shown you why the Ruy Lopez is such a liked opening, which I have only tackled from the white side in this post, and clearly, black's side has its own merits in the Ruy Lopez compared to alternative options that are available for black against 1. e4, but that's a discussion for another time.


How should one respond to the Sodium attack? The Sodium attack is characterised by the move 1.Na3, tending to be followed by the fianchetto of the bishop. This opening has never been played by myself, but I seem to encounter it quite frequently amongst lower rated players. What would be the best way to respond?

Play whatever.

Two-three moves like that hardly constitute an "opening". It could help if you told us what kind of set up white tries to achieve in the center (e.g. which of the central pawns are moved.)

Generally moves like that are nothing I'd worry about. Playing just normal moves (occupy the center, develop pieces, take it from there....) should be fine. If you have a favourite black opening against say d4 or e4 you might be able to follow it.

You might want to make the somewhat fundamental decision on whether you prefer to block the b2 bishop by playing e5 at some point or to limit the space for the a3 knight by playing d5.


Intervening with swiss pairing In connection with the Hou Yifan incident in Gibraltar I read that when doing the pairings they avoided matches between players from Iran and Israel (for whatever reason...).

How is this technically done in a Swiss pairing system? Is there an option in the pairing program to set this? Algorithmically, is it done in such a way that these matches are considered played already (through some flag "playedAgainstEachOther=true") or in some other way?

Is there an option in the pairing program to set this?

Of course.

Different approved Swiss pairing programs will do this is different ways. You should check out the User Manuals for the different programs to see how this is done.

For instance, in the Vega program go to the File menu, Round Manager, Avoid Pairs option and you can specify groups of players who should not be paired against each other for certain rounds. Generally speaking this should not be done in the last round where one of the players is on more than 50% even in the case of Iranian v Israeli since this can affect prizes and important placings.

  Algorithmically, is it done in such a way that these matches are
  considered played already (through some flag
  "playedAgainstEachOther=true") or in some other way?

This is a programming question rather than a chess question and does not belong here.


I need help Identifying where exactly this set came from I need help Identifying this.
My grandfather was in ww2 and at one point in the navy he went to Russia and met a Russian Naval Officer to whom he traded for this set, and the officer said he got it from his grandfather, but I'd like some true speculation on it please.

Here's the same set on ebay. More pictures of yours would be helpful.

https://www.ebay.com/itm/Vtg-Ceramic-Duncan-Medieval-Style-32Pc-Chess-Set-Hand-Painted-Faces-Detailed-74/263416351119?hash=item3d54d6898f:g:GaoAAOSw4A5Y0WX2

Perhaps the seller can help you learn more.

If you Google for "ceramic duncan medieval chess", you'll get a lot of hits.


Has the performance of physical electronic chess sets increased similarly to the performance of software based implementations over the years? From what I understand, the difficulty of most chess engines is determined by how long they are allowed to 'think' about the moves. From what I understand, the performance of software based chess applications has increased massively over the years, but I'm not sure if hardware limited engines have increased performance in a similar fashion.

The reason I ask is because my father owns a fairly old electronic chess set, but finds that the advanced levels take too long to compute their moves. I'm wondering if I buy a more modern board, can I assume that a similar level of difficulty can be achieved with less waiting time? For specifics, he already owns a systema Jupiter board, and I'm currently thinking about the Lexibook chessman elite, which is on the cheaper side of things.

Apologies if this doesn't fit the site's remit, it seems an appropriate place to ask.

There is are basically two features you can look at to decide whether a board computer will be faster: Elo (i.e. playing strength) and processor speed.

The stronger the maximal playing strength the faster it should be (on comparable levels). Lexibook Chessman Elite should be around 1800, whereas Systema Jupiter Deluxe plays at appr. 1400 Elo.

I couldn't find the chip speed for Systema Jupiter, but Lexibook has a 2 MHz chip. On this list you can look for something maybe a little faster and a little stronger, though at some point you may have to worry whether the weaker levels are still weak enough.

I would say that Lexibook, being 400 points stronger, should be comfortably faster than Systema Jupiter.


Looking for an opening that had been wrongly evaluated for years I'm looking for an opening I saw in a book (not a chess book). The opening was about 10 moves long, and the author stated that the evaluation after the last move shown had been considered for many years in many chess books as "black has a slight advantage", but later it had been shown that white could checkmate in 1 move.

Additional information: the book I read was written by Martin Gardner. It was not a chess book, but possibly a collection of his Scientific American columns, published in the 60s - 80s. This chess opening was (if I remember correctly) an example in a chapter devoted to puzzles and problems, unrelated to chess, that had been published with a wrong solution, or with a solution that later had been improved.

Maybe Martin Gardner was writing about this story. I'm quoting from p. 95 of Irving Chernev and Fred Reinfeld, The Fireside Book of Chess, Simon and Schuster, New York, 1949. (Of course they gave the moves in descriptive notation.)

  In the eighth edition of a popular manual by Dufresne and Mieses, the following line of play is given:

[FEN ""]

1.d4 d5 2.c4 e6 3.Nc3 c5 4.Nf3 cxd4 5.Nxd4 e5 6.Ndb5 d4 7.Nd5 Na6 8.Qa4 Bd7 9.e3 Ne7

  In this situation, the authors' comment is, "Black has the superior position." What the analysts seem to have overlooked is that White can mate on the move!

I'm guessing Kt-B3 was somehow typoed into Kt-K2.


A chess story about three sailors There was a book of chess stories that I had read some time ago. In one, there were 3 sailors who had made a deal with Devil for a crystal because of which they were unbeatable at chess. They saw the move that they were to make in the crystal after each move of the opponent.

Any ideas as to the story title?

The story is "The Three Sailors' Gambit" (1916) by Lord Dunsany, who was an interesting character. Besides being a prolific writer, he was a winner of the Irish chess championship, and he managed a draw during a simul by Capablanca. Dunsany was also a problem composer, some of them fairly typical chess problems and some of them more offbeat:

White to Mate in 4

This is very much a tricky problem.


Is the Spanish opening better than the Italian opening (for white)? I am currently playing the Italian opening with the white pieces.
[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.Bc4

I have been training with a higher rating player, who suggests to switch to the Spanish opening(Ruy Lopez).
[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.Bb5

I would like to ask, is the Spanish so much better than the Italian that it makes it worth changing? Furthermore, in the Spanish opening, does black have sharp variations that could be used against white?

Let us start with the Italian game.

Although it was long long ago since I was playing this opening, there are good reasons why it is not played anymore. The main reason it is not popular anymore is the failure of the Moeller attack*:

[fen ""]

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4. c3 Nf6 5.d4 exd4 6.cxd4 Bb4 7.Nc3 Nxe4 8.O-O Bxc3 9.d5 Bf6 10.Re1 Ne7 11.Rxe4 d6 12.Bg5 Bxg5 13.Nxg5 h6 ( 13...O-O 14.Nxh7!= ) 14.Qe2 hxg5 15.Re1 Be6 16.dxe6 f6 17.Re3 c6

In the old days people played Moeller attack and in the beginning things were good for White-sacrifice a pawn and get strong initiative-but Black found a way to defend the attack-see the lines above-and the main line was destroyed. White tried with quiet d3 and to prepapre d4 like in the Spanish game ( Ruy Lopez ) but had no success.

People tried with Scotch gambit-mainly Max Lange Attack-but Black did not need much time to find antidote-that line failed White too so it was abandoned.

Same happened with Traxler attack and it was abandoned too.

Evans gambit had the same faith-I think Lasker was the one who proved that Black can at certain point return the pawn and obtain better chances due to better pawn structure.

Nowadays, people seek various ways to improve these old lines but nothing tangible was found-either Black can sidestep the improvements or they give equal play.

Now the good stuff-Ruy Lopez! After the moves:

[fen ""]

1.e4 e5 2.Nf3 Nc6 3.Bb5

we reach the tabia. We notice that there is no symmetry like in the Italian game. Also, an important thing with Ruy Lopez is that White exerts MAXIMUM possible pressure on the center-that is the reason why it is better than Italian game, where center control is divided equally.

Because Black is under pressure he needs to make concessions, usually via a6 and then b5 to chase away the bishop-which leaves him with weak c pawn. Because of advantage in the center and healthier pawn structure White has a long initiative and Black needs to play carefully to free himself. This usually manifests in White having a king side attack, or slight but long lasting positional pressure.

Furthermore, in Spanish game, White can create center formation he likes thanks to his flexible d4+e4 pawn phalanx, something he can not do in the Italian game. This means that White can play with fixed center ( pawn e4 vs e5 ) , semi open center ( pawn e4 vs d6 ) or closed one ( e4+d5 pawns vs d6+e5 ) and that gives him opportunity to try various transpositional tricks to outsmart Black-something that Italian game can not give you since the center is fixed and symmetric.

To summarize:

Ruy Lopez gives you a slight advantage in center, slight initiative, great flexibility in steering the game, healthier pawn structure and great transpositional resources to outsmart your opponent.

If you wish to improve as a player you should play this opening for a while, so you can learn how to play with different center formations and it is good for practicing how to "cash in" the king side attack.

  Futhermore, in the Spanish does black have sharper continuations that he can throw against white?

Yes he does-the variation you seek is Marshall attack. It is very dangerous and being based on positional grounds i doubt a refutation of this gambit can be found-I think the current theoretical standing is unclear. Be warned, you must know theory very well to play against this line.

If you have further questions leave a comment and I will respond.

Sorry for incoherent answer, I wrote thoughts as they came to me. I could write a small book on this topic-there is so much to say about this-so if you need further information feel free to ask.

EDITED ON OPs REQUEST:

  I am trying to understand if it is a lot better or only slightly better.

It is way better than Italian game.

Black defends statically in Ruy Lopez, there are no counter-attacks ( except Marshall attack of course ) so he needs to suffer a little in order to get counter-play.

Since you have ideal center-d4+e4 pawn formation-you have slight space advantage. You also decide what type of game shall be played-open or closed-depending on your decision to close or open the center.

You get king-side attack and Black needs to defend himself-his counter-play on the queen-side is not sufficient. Be warned-Ruy Lopez is highly complicated to play for both sides but that is the reason people play it with both colors-because both sides must play accurate.

The reason I would not recommend it for Black is because Black lacks active counter-play so he needs to defend for a long time, before he generates chances and that is just too much for me.

Generally speaking, White has easier play in the Ruy Lopez, he "calls all the shots" most of the time and Black needs to repel White's threats first, and only then try to generate counter-play.

This is one of the main reasons why Black often answers to 1.e4 with Sicilian or French defense.

This was my opinion, supported by my current knowledge and experience in the Ruy Lopez and Italian game.

I must say that I have stopped playing 1.e4 long ago and that many things might have changed today but to test my claims it would be best to obtain good repertoire books on Ruy Lopez ( although I strongly believe that conclusions from those book will mainly support my conclusions ).

Hopefully this answer sheds some light.

Best regards.


Can I hover my finger over a chess piece without touching it in a major chess tournament? Noob question: I am aware of the no-touch rule, but can I point or hover my finger over a chess piece in a major tournament? To clarify, let's say it's my turn and I am thinking about which piece to move, and part of my thinking process is to move my finger from one piece to another without actually touching any of them, thus not violating the no-touch rule. To me, it appears that in spirit, it is very much like touching the piece except there is no touching; so is it legal to do that? Spirit aside, is there any law in the book or in any of the major chess tournaments addressing this concept?

Hovering your hand over the pieces does not violate the touch-move rule, but it is bad etiquette and arguably violates the rule against annoying your opponent ("It is forbidden to distract or annoy the opponent in any manner whatsoever.", say the FIDE Laws of Chess, §11.5 in the 2018 edition.)
Here's the explanation given in Chess for Dummies:

Furthering the touch-move rule, a frequent cause of complaints is the hand hover. The hand hover occurs when a player positions his hand over a piece and leaves it there. The hand hover is a distraction, and you shouldn’t do it — so goes the warning by José Capablanca. You should never obscure your opponent’s sight of the board unless you’re in the act of moving, so don’t reach for a piece until you’ve decided to move it.


Could this kind of inaccurate sacrifice be countered? I recently played a Lichess Bullet Game as White.

[FEN ""]

1.e4 e5 2.h4 Nc6 3.d3 Nf6 4.g3 Bc5 5.Nc3 d6 6.a3 O-O 7.b4 Bxf2+ 8.Kxf2 Ng4+ 9.Ke1 a6 10.Bh3 Nd4 11.Bxg4 b5 12.Bxc8 Rxc8 13.Nge2 Nxe2 14.Qxe2 c5 15.bxc5 dxc5 16.Rb1 c4 17.dxc4 bxc4 18.Be3 h6 19.g4 f6 20.Bxh6 gxh6 21.Qe3 Kf7 22.Qxh6 Ke7  23.Rb7+ Ke6 24.Rf1 Rh8 25.Rxf6+ Qxf6 26.Re7+ Kxe7 27. Nd5+ Kf7 28.Qxf6+ Kg8 29.Ne7+ Kh7 30.Qg6#

After Black's 24th move, I thought I was doomed, but I found the rook sacrifice, Rxf6, which forces Black to capture Qxf6. I could have gone for Rb6+ next, taking their queen, but I missed that and played Re7+ sacrificing both rooks. They had to capture with the king, and now, what I foreseen, is that Nd5+ forks the Black king and the queen.

My question is this: If Black ran better with his King, would they have a chance to defend against my attack? It seems to me that d7 is not a better square for black to move his king to because he has to block Qe7+ and there is also the Nb6+ threat of forking the rook. It's possible that their next best move would be Rce8, which is met with 1. Qf7+ Kd6 2. Qc7+ Ke6 3. Qc6+ Kf7 4. Qf6+ Kf8 Ne7+, forcing him to take with the rook, because otherwise it's mate. It looks like the game was mine anyways.

Nevertheless makes for a more spectacular win.

When asking questions about tactics and sacrifices, chess engines are usually the most efficient and accurate way of determining the answer. The following is based on analysis from Houdini 6.03 in tactical mode:

By the end of move 24, in the following position, a forced mate (in 8) already exists for white

[FEN "2rq3r/1R6/p3kp1Q/4p3/2p1P1PP/P1N5/2P5/4KR2 w - - 5 25"]

1.Rxf6+ { #8/58 } 1...Qxf6 2.Rb6+ Rc6 3.Rxc6+ Kd7 4.Qxf6 Rh6 5.Qxh6 Ke7
6.Rc7+ Kd8 7.Qd6+ Ke8 8.Qe7#

And Rxf6+ was indeed the optimal move. Later on, Rb6+ was completely fine, but not optimal (see analysis above). As it turns out, you lose your mate in 7 and are tragically left with the following mate in 19:

[FEN "2r4r/4R3/p3kq1Q/4p3/2p1P1PP/P1N5/2P5/4K3 b - - 1 26"]

1...Kxe7 { #19/50 } 2.Nd5+ Kd7 3.Qxf6 Rhf8 4.Qe7+ Kc6 5.Nb4+ Kb5 6.Qxe5+ Kb6 7.Qd6+ Kb7 8.Qxa6+ Kc7 9.Qc6+ Kb8 10.Qb6+ Ka8 11.Nc6 Rxc6 12.Qxc6+ Kb8 13.Qd6+ Kc8 14.Qxf8+ Kd7 15.e5 Ke6 16.Qd6+ Kf7 17.Qf6+ Kg8 18.h5 Kh7 19.h6 Kg8 20.Qg7#

It turns out the best move for black (the one which holds off mate for longest) is in fact to take your rook and allow themselves to be forked.

On move 27, the played move Kf7 allows the mate in 3. The best option, Kd7 is shown in the mating line above. It delays mate much longer than 3 moves, but obviously still loses.


Cases of grandmasters renouncing titles, tournament victories, etc? Apart from Bobby Fischer "renouncing", in a sense, the World Championship title in 1975, are there any other famous cases from chess history of strong players voluntarily renouncing titles, tournament victories, and the like, for personal, political, religious, or other reasons?

I have been playing tournaments for 39 years, 34 as a USCF Master, so I follow chess closely; but other than Fischer, I have never heard of anyone doing it voluntarily DURING their reign. Alekhine is the only other male World Champion not to defend his title, but did it involuntarily (he died). :)

Other cases of not defending their title include Hou Yifan, who decided not to defend her Women's World Championship title in 2015 due to another commitment, and after winning it back in 2016, again she chose not to defend in 2017 protesting the knockout system (I do not blame her).

Of course, some have not defended their lesser titles for various reasons, like political and moral. Anna Muzychuk refused to defend her world titles in rapid chess and blitz in 2017 due to Saudi Arabia’s treatment of women.

I have heard of a few, who were stripped of their titles like GM Gaioz Nigalidze for computer cheating (demoted to IM). GM Igors Rausis is most likely facing the same sanctions for his recent cheating incident (He admitted it, and announced his retirement).


Is there an online chess evaluation engine with a REST API? Is there an online chess evaluation engine with a REST API? I'd like to be able to send a game or position (with castling ability presumably) to a simple REST API and get back the positional evaluation from a reasonably strong engine.

It is pointless to have a rest API for random position evals which have to be precomputed for near-instant response. In that case you might as well ask for an opening book. There are a few sites that with opening book querying tools, which are pretty close.


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

Is it possible to win this game theoretically?

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

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

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

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

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

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

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

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

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

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

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

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

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

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


How to add draw offer to PGN? Does PGN have any annotation for draw offer? Just adding = after a move doesn't seem to work everywhere.

Among the standard NAGs there's $10 (drawish position or even) which translate as = or I can use comment, but wondering whether there's a specific way of adding a draw offer.

There is no symbol for a draw offer. Just add a comment {draw offered}


In Hand and Brain chess, is the stronger player generally preferred to be the hand or the brain? Exactly what it says on the tin, as the British say:

In Hand and Brain chess, is the stronger player generally preferred to be the hand or the brain?

And secondarily:

Is the answer to the previous question affected at all by the particular relative strengths of the players (as in, is the answer for a team involving Magnus Carlsen and I (probably around 1200) substantially different than that for team involving a 1600 and an 1800)?

I can think of good reasons for both: the stronger player being the hand might be nice because they could select the best move under some constraints, and thus only very rarely make an outright blunder (generally, the only way they could play an outright blunder (assuming they're strong enough to pretty reliably avoid blunders) would be is a piece was chosen that had NO good moves, which I think is probably pretty rare). On the other hand, a stronger player being the brain might be preferred, as they could narrow down a decision tree for the lesser player in the hopes that the best move might become easier to see without such a large tree to analyze.
To be clear, Hand and Brain chess is a type of team chess in which two players play each side. One (the "Brain") is only allowed to pick a piece type to be moved, and the other (the "Hand") must move that piece type without knowledge of what the first player intended. For example, if the "Brain" says "pawn", then the "Hand" must move one of the pawns. If the "Brain" says "king", then the "Hand" must move the king (includes castling).

Not a definitive answer, but I'm posting my comment based on the upvotes it received.
It depends. GMs have different opinions.
GM Hikaru Nakamura has said it really depends on the situation. Additionally, he has commented that when the Brain, he often suggests moves that aren't correct because he is factoring in the likely Hand response to his move.
GM Aman Hambleton stated the stronger ELO player should be the Hand generally because they will find good moves in most cases, and be able to identify a plan for a position much easier.


How fast can checkmate occur by just moving the king? How short can a game be in which (after the first move) one player moves only their king, and yet checkmates their opponent?
This is assuming that the players cooperate, i.e. this is a kind of "helpmate." This generalizes a problem by Stanley Rabinowitz, 1596 Journal of Recreational Mathematics 1987. No peeking at his solution, please! :D

Here is a starter solution in 7 moves.
Can we do better?
[FEN ""]

1.g3 e5 2.Bh3 Ke7 3.Bxd7 Kxd7 4.Kf1 Ke7 5. Kg2 Ke6 6.Kh3 Kf6+ 7.Kh4 Kg6#

If this is best, interestingly, the play is almost forced. The only variations are 4... Kd6 or 4... Ke7 in the line above. There is also 4... Ke6 and 5... Kf5, or 3. Kf1 Kd6/Ke8 4. Bxd7 Kxd7 5.Kg2 Ke6, etc. Only five possible move orders with such a minimal stipulation would be quite nice.


Are there any computer vision chess programs which can be used for online games? I want to play online chess with a real chess board.  I learned that lichess can read the opponent's moves out loud, so I don't have to stare at the screen, which is a good start.  Now I need a way to send my moves to the PC.
I don't have a few hundred dollars laying around to buy a DGT board, but I do have a webcam, and I know that computer vision chess is a hot topic of research- I've seen many demonstrations on youtube.  Is this technology available yet for online play?

It seems this GitHub project provides what you're looking for:
"Program that enables you to play online chess using real chess board. Using computer vision it will detect the moves you make on chess board. After that, if it's your turn to move in the online game, it will make the necessary clicks to make the move."
https://github.com/karayaman/Play-online-chess-with-real-chess-board


PGN format and comments with tag pairs Currently making a parser for PGN files. And wondering if there is any practice of using commentary in Tag pair section, like:

[Event "Tournament X"];hosted once a year

[Event "Tournament X"]{hosted once a year}

Has anyone seen such PGN? Is it used? Cause I couldn't find no such clause in PGN standart that forbids such comments. Or it's me that's just blind...

The first example is invalid in PGN, please don't do that. Your second example is also invalid. We don't put comment to the same line as the header.


Is there really a checkmate after 1... Bxf5? This puzzle on chesstempo caught my eye. We play as Black:
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 0 1"]

1.Rgxg5

Note: the solution is not quite important here, so no large spoilers from me :).

The main blunder here is playing 1... Bxf5. One of the comments runs:

...Black is a step away from certain death after 1...Bxf5 2.Qxf5...

They show this board:
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 1 1"]

1.Rgxg5 Bxf5 2.Qxf5 Qd1+ 3.Rg1 Qd2 4.f7 Qf4 5.Qe6 h5 6.Rg8+ Rxg8 7.fxg8=Q+ Rxg8 8.Qxg8#

Is mate threat really a thing here? I believe the mate threat actually begins at 3... Qd2 4. f7. Here's how I would've answered:
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 1 1"]

1.Rgxg5 Bxf5 2.Qxf5 Qd1+ 3.Rg1 Rxd5

I reckon 3... Rxd5 to force White into some exchange, as merely playing 4. xd5 would end up in a mate threat from Black:
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 1 1"]

1.Rgxg5 Bxf5 2.Qxf5 Qd1+ 3.Rg1 Rxd5 4. cxd5 Qxd5+ 5. Rg2 Rg8

The exchange would be:
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 1 1"]

1.Rgxg5 Bxf5 2.Qxf5 Qd1+ 3.Rg1 Rxd5 4. Rxd1 Rxd1+

So, who is wrong here? Am I failing to choose the best moves for White, or is the board in the comments actually faulty?

I Suspect that after 3... Rxd5 4. f7 is strong enough:
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 0 1"]

1.Rgxg5 Bxf5 2. Qxf5 Qd1+ 3. Rg1 Rxd5 4. f7

The obvious threat is Qf6 mate. Starting with the variations in which black tries to cover f6 we have:

If 4...Rb6 then 5. f8=R#
If 4...Rd6 then 5. Qxe5 Rf6 6. Qxf6#

Since all variations leads to checkmate there is no way to cover f6 and black must resort to giving up the queen.
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 0 1"]

1.Rgxg5 Bxf5 2. Qxf5 Qd1+ 3. Rg1 Rxd5 4. f7 Qxg1 5. Kxg1

Yet again Qf6 is mate and obviously black cannot move the rook from the 8:th rank because f8 mate. If 5... Rd6 then 6. Qxe5 Rf6 7. Qxf6#. This leaves us with the one last try of Rd1+ (if Kg7 immediately then cxd5):
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 0 1"]

1.Rgxg5 Bxf5 2. Qxf5 Qd1+ 3. Rg1 Rxd5 4. f7 Qxg1 5. Kxg1 Rd1+ 6. Kg2 Kg7 7. Qxe5+ Kxf7 8. Qxb8

It is not a mate but undoubtedly white is winning


Stockfish blunders away a piece Using stockfish_8_x64 with Arena 3.5.1, I see a weird pick by Stockfish.  Start here:

White, Stockfish, to move.  It plays bb6-g1,losing the bishop and the win.

Also strange:  the same engine does not make this weird move in the Tarrasch program.  Playing with KBN against K, I've seen Stockfish often blunder away the advantage in these endgame setups.

Any clue how this could be happening, or why it would happen only with Arena?

EDIT:  SmallChess answer is correct.  The problem was a residual, non-zero value in the position "number of half-moves" setting.  See my reply to his posting for more information.

This is not a blunder, expected behaviour from the engine. Everything worked as intended. Try to copy the FEN string out, and you'll know.

Although the position looked winning, White didn't have enough moves to force checkmate before the 50 moves rule. Stockfish, knowing the position was a dead draw immediately asked for simplification.

The position you had is 100% equal, there was no way to win it. It's a draw. What Stockfish did was not wrong.

If the Tarrasch program didn't send out the 50 moves counter to Stockfish, you'd never get the problem on Tarrasch. If that was the case, it was an error in Tarrasch because the 50 move counter is part of the game.

Solution?

Setup a new board with the same position but reset the 50 moves counter.


If a player is significantly behind in time, does it mean he's bound to lose? Let's focus on FIDE classical chess finals historically.

Caruana is always behind in time control, thinks more, waste more energy.

Statistically speaking, did the players who played faster won more titles? Is Caruana showing signs of weakness?

I don't know about statistics, but I do know that they are not "bound" to lose. It depends on the position. Is it easy to play, or is it a very sharp, tactical position? Also, is there a time-increment? Often, in classical FIDE games, there is. Based on experience, I can tell you that it can be very stressful being low on time in a long game, even if there is an increment. However, if psychological (personal) influences are ignored, it very much depends on the position and on the time-increment.


Brain fog when playing chess I've been playing chess from many years but started playing more from past few month. I only play 3 minute blitz games, have rating around 1350 in chess.com and 1700 in lichess, have played few thousand games till now.
I observed that sometimes my brain just doesn't seem to work and am unable to find even the simple moves fast. I won't be able to think few moves ahead. I keep losing games continuously till my rating goes down by 100s of points. This happens for days together. And sometimes, it magically happens that my brain works quick, analyses and find the best moves naturally without any strain.
Does anyone feel the same when playing blitz games? How do you bring yourself into 'that sweet spot' where the brain is active and quick?

I think what you are experiencing is fairly common. I find that I have games that i feel like an absolute legend, able to come up with creative solutions and just not making any mistakes.... then there other games where i hang pieces , miscalculate large trades and just can't get things to click.
I think its partially due to fatigue though. If you are playing game after game after game, especially with blitz , theres little time to think and your brain starts to fatigue and you start making mistakes.
I think the best way to do deal with this just recognizing when you are starting to get fatigued and take a break. I find puzzles are really good for helping me with this. I usually do puzzles for half an hour, take my time try to calculate things out a little. then have a cup of tea, then good to go.


How can I send a UCI command to a chess engine in Python? I have a followup question to my previous thread:
Python script to let stockfish selfplay 10 games from a given position

There are some engines that allow you to set a command that imposes that the hash memory is never cleared among games. For instance the Sugar program by Marco Zerbinati has this UCI command that can be done from the command line:

setoption name NeverClearHash value true

I tried to do this command in python-chess library but apparently it doesn't work:

engine.options["NeverClearHash"]

How can I set the option "NeverClearHash" to "true" in Python?

First, engine.options["NeverClearHash"] is wrong on two counts.
It is engine.option, not engine.options and that command queries the value rather than sets it.

To set the value you have to do something like:

engine.configure({"NeverClearHash": 1})
or perhaps:
engine.configure({"NeverClearHash": true})

Good programmers are never too proud to read the manual. I wholeheartedly recommend it.


Can a computer have a good tournament? Tournament players can "have a good tournament" because of the psychology involved, so their playing strength will vary from game to game. Do computers play at a constant strength all the time, or do they have the occasional bad tournament?

We're going to assume there is no hardware issue, as pointed by Tonny Ennis in his comment.

It's possible that a computer engine experiences a "bad" tournament, but it's extremely rare. When we say "bad", we don't mean collapsing like blundering pieces, it's more like not getting a good position suitable for the engine. Computer engine always play at a constant strength, dictated by the algorithm. They won't do anything other than what the algorithm tells it to do.

Let's give an example, it's well known Komodo is a better engine than Stockfish in a strategic position. If we randomly choose the openings in a match of four. We might see a closed position in three of those games. As expected, Komodo outplayed Stockfish in those three games. The final score would be 3-1 in favour of Komodo.

Does that mean Komodo is a much stronger engine than Stockfish? Probably not. Can we conclude Stockfish had a "bad day"? Maybe. But please remember the sample size is too small, what if we let them play more games? A typical computer chess tournament can have a match with over 1000 games. If we do it, we might see a very different result.

Conclusion: if we see a chess engine has a "bad day", usually it's because the sample size is too small or the testing condition is biased. The law of large number will erase unsystematic variation given enough sample size.


E-Ink/Digital Paper for Display I like to play with my favourite android chess app on a tablet.

On the other hand I like the sun in my room.

I the sun is too strong, then up to now I go to a dark area in my room.

Is there a way to solve this?

Is there a way to show the chess board on E-Ink (digital paper)?

As of 2016 There are a few Android based e-ink readers, most notably by Onyx and a whole bunch of rebrands ranging in size from 6 inches to 9.7 inches.

I highly recommend checking out mobileread.com for all e-ink reader related information.

Usually they do not run the latest Android (i think 4.4.2 is about as good as it gets).

Another minus is that they do not run the most powerful CPUs(to both save on costs and also to preserve power). Still for running Stockfish they should be good enough.


What does black achieve with 1.d4 c6? I have faced 1...c6 as a reply to my 1.d4 quite a few times recently, and this makes me wonder why people play this as oppose to 1...d5.

In addition to playing the Slav with 2.c4, I have an option of playing the Caro-Kann with 2.e4, so I have an extra option and black has nothing in return that I can see.

1...c6 happens at top level, but fairly rarely (9th most popular response, behind 1...Nc6 according to lichess database).

Why do some players choose this move order?

You're right that players who choose 1...c6 must be fine with the Caro-Kann, which is one reason why it's not that popular. However, there are some people who are fine with the Caro-Kann, and so the move gets played occasionally. In the case of 2.c4, there aren't many benefits I can see for Black. He has the option of playing a la King's Indian with ...Nf6, ...d6, etc, but it wasn't necessary to start with 1...c6 to do this.

There may be some minor benefits to 1...c6, but they're not obvious to me. This is why the move isn't played often.


Openings for pawn storms I am a weak player and I always will be. After completing the opening I have no idea what to do and, since a bad plan is better than no plan, I decided to do this from now on in every game:

wait for my opponent to castle;
castle in the opposite side;
start a pawn storm.

My usual opponents are even weaker than me, so I really think it can work, and I expect it to be more enjoyable than just wait for a tactical mistake.
My question is... what kind of opening repertoire is most suited to implement my plan?

Since your opponent is most likely to castle short, you have to choose lines where long castling (for you) is reasonable.

With white I would suggest 1. e4, and against 1... e5 the Center Game 1. e4 e5 2. d4 exd4 3. Qxd4 Nc6 4. Qe3.

[Title "Center Game"]
[FEN ""]

1. e4 e5 2. d4 exd4 3. Qxd4 Nc6 4. Qe3

Against 1... c5 you can play the Open Sicilian (2. Nf3 followed by 3. d4).

Against other black defenses you can find lines with long castling as well.

With black it's more difficult. You could try the French Winawer

[Title "French Winawer"]
[FEN ""]

1. e4 e6 2. d4 d5 3. Nc3 Bb4

against 1. e4 and the Albin Countergambit

[Title "Albin Countergambit"]
[FEN ""]

1. d4 d5 2. c4 e5 3. dxe5 d4

against 1. d4.