King's Indian Attack plans for White after Black plays ..dxe4 and ..e5 I always play the King's Indian Attack against the French Defense. Most of the time, I get the position below and I couldn't think of good plans. What are the best ways for White to continue? I don't know where to put my Queen, the d2 Knight, and the Dark-squared Bishop. I am also afraid of the a- and b-pawns of Black when Black starts to move them forward.

I play the KIA because I like closed or semi-closed positions. I don't really like open games. But my opponent has started to open the game by playing this position always.

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
1. e4 e6 2. d3 d5 3. Nd2 c5 4. g3 Nc6 5. Bg2 Nf6 6. Ngf3 Be7 7. O-O O-O 8. Re1 dxe4 9. dxe4 e5

This is my first time answering a question, so i hope that will be all right :)

First of all, the position appearing on the board is also reached via this move order: 1. Nf3 d5 2. g3 c5 3. Bg2 nc6 4. O-O e5 5. d3 Nf6 6. Nbd2 Be7 7. e4 dxe4 8.dxe4 and it's a tempo up for black, and the extra move might be important. And secondly we might reach this position with colors reversed: 1. d4 Nf6 2.c4 g6 3. Nc3 Bg7 4.e4 d6 5. Nf3 O-O 6. Be2 Nbd7 7. O-O e5 8. dxe5 dxe5 etc. And it's very important to notice that the examination of similar positions provides complete understanding of ideas.

Bypassing the move order and transposition issues, I would like to mention the related article named "The King's Indian Attack (from White's Viewpoint)" (page 142) on the excellent book Opening Preparation by Dvoretsky (1996), Dvoretsky came to the conclusion that this exchange (...dxe4 and ...e5 by Black) is dubious. The reasoning behind Dvoretsky's assessment is:

  "Not a good exchange. White now has a clear plan for playing on the weaknesses c4, d5 and f5."

In the game (which cannot be found in databases) Dvoretsky - Rogozhnikov, Moscow 1965 White executes his plan by playing, c3, Qc2, Nf1 and exchanging the defender of d5 square by Bg5-Bxf6 and after Ne3, Bf1 and Bc4, and exchanging the best defender, the light-squared bishop on e6. It should be noted that Dvoretsky's opponent defended weakly and lost after a beautiful positional squeeze. But it's not clear how White will react after the correct a timely ...h6 and countering the White's plan by trying to push ...c4 by ...b5 or ...Na5
Maybe the answer is the mixture of the whole ideas given, let's say, Nc4(Nf1)-Ne3 and Nf5 and after an exchange on f5 to take with exf5 and play with the strong bishop g2 and full control on the light squares. There are many typical master games with both colors. You might want to search the other transpositional options in order to achieve complete understanding of the ideas, because there are hundreds of master games beginning from those positions with both colors. I hope I might be able to help you.


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

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

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

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

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


Max Lange Attack - Materials to Study I am looking for quality materials such as books, magazines and video series to help me to study Max Lange Attack. I'll be grateful if you recommend one and share the link.

Thanks.

Two other sources:

Dangerous Weapons: 1 e4 e5 (2008) by Emms, Flear and Greet has a chapter on the variation with 8. fxg7.

Beating the Open Games (2007) by Marin also has a chapter on the Max Lange Attack. The nice thing about the latter book is that you can find an update for free at the site of the publisher. The Max Lange Attack is discussed from page 35 in the pdf document.


KRPP vs KRP - maximum depth to conversion? I am trying to learn single rook endgames with two pawns against one, with added stipulation that the two pawns of the attacking side are on neighboring files with the pawn of the defending side also on one of those files. It could for instance be e+f pawns vs f pawn or g+h pawns vs g pawn.

What is the most complicated such position that is still won for the attacking side? To make the question precise, I am asking for the position with the maximum depth to conversion.

As Glorfindel notes,
the Lomonosov tables are great but might not have the answer you want.
In RPP/RP, according to the list in
this
article by Guy Haworth, we find that the maximal distance to mate
is 200+ moves, from the following position -- which happens not to have
the White pawns connected, but worse for your purpose,
it looks like most of the play is post-conversion:

[Title "Black to move; White eventually wins"]
[Fen "8/k1P5/8/8/1R5P/7p/r7/1K6 b - - 0 1"]
[StartFlipped "0"]

1...h2 2.Kxa2 h1=Q 3.c8=R!

after Kxa2 we're in 6-man territory, and the k4it.de site says
"Win in 216" starting Qd5+ 4 Kb1 Qa5(d6) -- that's right, not Qd1(h1)+,
which lets White win in only 200, nor Qd3+, which hastens the end
by another move (199).

Possibly Guy Haworth has enough access to 7-man tables
to get the answer to your query.


Creating chess engine, machine learning vs. traditional engine? I am both an avid chess player and computer programmer. I would say that playing chess and programming are the two things I spend the most time doing. Naturally, I am wanting to create my own engine and, ultimately, Lichess bot.
In wake of AlphaZero's crushing performance against Stockfish last year, I am considering whether I should create this engine with machine learning (some type of neural network, possibly using Tensorflow) or traditional, hard coded heuristics.
I am less familiar with neural networks than other kinds of hard-coding. Still, it could be a good way for me to learn to work with neural networks.
Another thing I am considering is whether it is important which language I use to code the engine. I know many chess engines use C++, which I have never used before. I have used other C-based languages which do many of the same things, with mostly varying syntax. I am most familiar with Swift and Javascript, but am also familiar with Python and feel that it could do the trick for me.
So, in terms of creating the strongest chess engine possible, should I go neural network or hard-coded?
Update:
I am writing a traditional engine in C++. It is currently somewhat UCI compatible and plays at what I estimate is 1100ish ELO. But it generates legal moves and I’ll be posting updates here.
This is the link to the github repo for the engine. Feel free to fork and make PRs, or just make general suggestions/tips.

If you're trying to make the strongest engine possible, absolutely go for NN engines.

Traditional engines are great - Stockfish is arguably still the strongest engine on the planet on consensus equal hardware - but they are hard to write. These engines didn't get where they were overnight; they took years and years of work. Stockfish for example has been steadily gaining elo for six years. If you start from scratch, you will not get anywhere near Stockfish strength quickly; in fact you are likely to stall several hundred elo from where Stockfish currently is. For comparison some of the strongest single-author engines right now are Ethereal, Laser, and Xiphos (I neglect Houdini & Fire since they aren't open source). These engines are all substantially weaker than Stockfish.

Why are they so much weaker? Two reasons:

At this level, developing an engine takes a lot of computational power. What you do is look through your code and identify an idea that could gain elo. An example idea is, "if we know this move is probably good, do not search branches that reverse that move" (if this doesn't make sense to you, it means there's going to be a high learning curve as well). You then write a patch that implements the idea, and test the modified engine against the previous version. At this level, it takes tens of thousands of games to get a large-enough sample size to tell if the patch is effective. Playing these games takes huge amounts of computational power. Stockfish has access to super hardware: as of time of writing, the Stockfish testing ground Fishtesting is running with 1038 cores. For comparison a typical desktop computer might have 4-8 cores.
The other reason is that Stockfish is backed by many brains. As of time of writing, there are 8 patches written by 5 people being tested. If you look through the patch histories you'll find many more developers who've written patches. I don't know how many active Stockfish developers there are, but it's certainly >20.

On the other hand, NN engines (relatively) easily reach a strength that's well above Ethereal/Laser/Xiphos. See for yourself in the latest Top Chess Engine Championship tournament. Ethereal/Laser/Xiphos are in League 1, which is credible enough, but the engines in the top division (Division P) are:

Stockfish (community-backed traditional engine, runs with Fishtesting)
Komodo (commercial traditional engine, has full-time developers)
Komodo MCTS (commercial semi-traditional engine, has full-time developers)
Houdini (commercial traditional engine, is a one-man effort, hasn't been updated for two years)
Leela Chess Zero (community-backed NN engine, runs with the analog of Fishtesting aka a ton of hardware)
AllieStein (2-man NN engine)
Stoofvlees (NN engine)
ScorpioNN (NN engine)

The last three engines - AllieStein, Stoofvlees and ScorpioNN - are all small collaborations by people who, as far as I know, are enthusiasts like you and not full-time developers. They've gotten to Div P strength after less than two years of trying (all these NN engines only appeared after AlphaZero). For comparison, in the recent history of computer chess there has only been one person who's ever written a traditional engine that competed successfully with Stockfish & Komodo on his own (Robert Houdart, the author of Houdini).

It's true that you probably won't have the hardware to compete with Lc0, but Lc0 takes this much computational power because it's a "zero" engine - it's supposed to play chess without any kind of human knowledge except for rules. You don't need to use the same methodology. You could use e.g. the Stein methodology that uses supervised learning. It's arguably even better than going "zero" - after all it's AllieStein playing in the superfinal, not Lc0.

The upshot is: if your aim is to compete with the best engines in the world, you are far more likely to succeed with NN engines than traditional ones.


Why 6.Nc3 in the following position in Grob opening? [StartPly "10"]

[fen ""]
1.g4 e5 2.Bg2 Bc5 3.e3 d6 4.d4 exd4 5.exd4 Bb6 *

In the Grob attack opening database posted in this answer the suggested next move is 6.Nc3. However, in most variations of Grob opening I looked at so far, c4 is played by White very early in the opening phase. In the above position I would pick it as the next move also.

Why is 6.Nc3 better for White here than 6.c4?

I don't think there is a drastic difference between playing 6.c4 than 6.Nc3, but from my perspective, I don't see much utility in the move 6.c4. What are you trying to achieve with 6.c4? It may seem as though you are expanding and gaining space and challenging Black's center, but Black can immediately put pressure on the d4 square with 6...Nc6 and you must defend with 7.Be3. Now, if you had played 6.Nc3, and after your opponent plays 6...Nc6, you still need to defend with Be3, but you have an extra developed piece. Note, you obviously don't want to play d5 (if you've already played c4) after 6...Nc6 since Black can play Ne5 or Qh4 and will have a better position than White. I'm no chess expert, but those are the very small differences I see.


Building a repertoire on lichess I have decided I wanted to understand one basic opening against 1. e4 and one against 1. d4 as black. After watching a few videos on multiple openings and systems, I decided I wanted to try and pick up the Caro-Kann. I was wondering if it's sensible to build an opening repertoire there. More specifically, is it possible to do it without chessbase? Is the free stockfish analysis reliable? What steps should I take to ensure my analysis isn't flawed?

Create a private Lichess study and add your game references there. As you keep adding more of your learnings and research, the study will develop into a full repertoire. You can also export as png, so you can always switch to other software if you find a better option.
https://lichess.org/study


Have there been computer-vs-computer chess games exceeding 493 moves? From a FIDE Online Arena Facebook post (which appears copy/pasted from elsewhere), I'm interested in the part in bold:

(Image of a chess board with two kings and no pawns nor pieces omitted.)
This was the position after 91.Kxb8 in the game NewRival1816 - Faile06 in a computer tournament in 2001. According to the rule, the game should have been stopped as a draw here, but this rule apparently wasn't implemented ... 493 moves is a new world record, ...

I find it hard to believe this is up-to-date, but I didn't immediately find examples to indicate otherwise (e.g. long computer chess games didn't give anything relevant).
Question: Have there been computer-vs-computer chess games exceeding 493 moves?
For this to be meaningful, I insist that both engines were actually playing "good moves", i.e., moves that both engines thought maximized its score.  Or in other words, the engines were actually playing chess, and not trying to maximize the length of the game.

Tim Krabbe discusses this in his website (see section 328).
It's an old post - dating to 2006 - so it's certainly possible. However 2006 was also a long time ago. Since then engines have gotten more familiar with the rules, and all the top engines I'm aware of are aware of the 50-move rule. 493 moves is very long, but it should still be fairly trivial to get longer games if one just got engines to play and never adjudicate (see example). All one has to do is set some very short time control and play a billion games, and eventually a game will get there.
Games played in tournaments is a different matter, with a necessarily small sample size. In that case I think it's quite likely that 493 moves is the longest on record. It's about 100 moves longer than the next-longest games I'm aware of.
Caveat: the 493-move game wouldn't happen under real tournament rules since the 75-move rule would've been invoked to force a draw.


Sicilian Najdorf, Sozin Variation e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bc4 e6

1) For 6. Bc4 Black can play immediately b5 and attack it. But almost all Grandmasters reply with 6....e6. Theory also stresses to 6....e6. Why not 6.... b5 to attack Bishop immediately as 5....a6 is already done? Is it not giving Black a strong attack against White? Hence, why Grandmasters are not playing early 6....b5 in their games? Expecting good answer. Thanks in advance.

6...b5 7.Bd5! Nxd5 8.exd5 leaves Black in trouble. The e-file has been opened and Black has to figure out how to castle before things get really heated. The c6-square is also a major weakness that White's d4-knight is ready to jump to at the right moment.


Paul Morphy vs Henry Bird missing games. The Historical Chess Ratings page claims that Paul Morphy played 12 games with Henry Bird, with a final score of 10.5 - 1.5 (Kasparov's book My Great Predecessors Part I also mentions this (page 55), claiming Morphy won 10, lost 1 and drew 1). However, I was able to find only 5 of these games online. Do we have a record anywhere of the moves of the other 7 games?

The five games mentioned might be the only games between Morphy and Bird that are preserved. Collections that claim to include all known Morphy games, only contain those five between the two, see for instance The full Morphy. Also, written accounts seem to suggest that the games they played were not part of an official match, they just played some games while Morphy was waiting for a reply from Staunton (Link).


Validate Engine moves using Perft and divide I'm developing a small Engine in Java, before trying something more elaborate in C/C++. Right now I'm running some perft tests (the 'perf_talkchess' file), but as expected it has some bugs. Consider this position:

FEN r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1

[fen "r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1"]

I wrote the following perft method:

    public long perft(int depth){

        List<Move> moves = board.getAllMoves(board.state.currentPlayer);
        int n_moves = moves.size();
        long totalNodes = 0L;

        if (depth == 1){
            return n_moves;
        }

        for (Move mv : moves){
            board.makeMove(mv);
            totalNodes += perft(depth - 1);
            board.undoMove(mv);
        }
        return totalNodes;
    }

My perft (4) gives 1184480, it should be 1274206. In order to debug the position, I wrote this:

   public void divide(){

        List<Move> moves = board.getAllMoves(board.state.currentPlayer);

        for (Move m : moves){
            board.makeMove(m);
            //ignore the 0 arg
            Perft p = new Perft(board.toFEN(), depth, 0);
            p.run();
            board.undoMove(m);
            System.out.println(m + ":" + p.result);
            total += p.result;
        }
        System.out.println("Moves: " + moves.size());
        System.out.println("Total: " + total);
    }

When I run

Divide d = new Divide("r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1", 3);
d.divide();

I got Moves: 26 Total: 1276215 and a very long output. I have 2 questions:

a) How do I properly write/use a divide algorithm?

b) How do I handle the castle state inside the make/unmake methods? What are the general traps to avoid regarding castle rights? I guess I'm screwing up the undo move code. What I do now is the following:

At makeMove I backup the current state before applying the move

makeMove(move)
  prevState.x = currentState.x
  prevState.y = currentState.y
  ...
  if (move.isFoo)
      change currentState accordingly
  ...

At undoMove I just restore the currentState and undo the board:

undoMove(move)
  currentState.x = prevState.x
  currentState.y = prevState.y
  ...
  if (move.isFoo)
      undo board state accordingly
  ...

Maybe there's some flaw with the reasoning above, I can post the code if necessary. Thanks!

Q1

I wouldn't code up a new divide function because if you have a bug in your code, your new function will also be buggy.

Why don't you use Stockfish? Do you know you can run perft on Stockfish?

In Stockfish, run the following:

position fen r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1
d
perft 3

You should get the following:

Position: 1/1
h2g1: 1160
h2g3: 1320
h2f4: 1444
....

===========================
Total time (ms) : 2
Nodes searched  : 27826
Nodes/second    : 13913000

Now you just need to add a std::cout to the perft function in search.cpp.

Find the function uint64_t Search::perft(Position& pos, Depth depth) { in search.cpp, then use it to print out all the positions in your perft search.

You can then compare your perft moves with Stockfish with the following Unix commands:

sort MyPerftMoves > MySortedPerftMoves
sort SFPerftMoves > SFSortedPerftMoves
diff MySortedPerftMoves SFSortedPerftMoves

Q2

You should use Zobrist hashing if you haven't. This is the standard technique for board representation in chess. In Stockfish, the code below does the trick for castling:

// Update castling rights if needed
if (st->castlingRights && (castlingRightsMask[from] | castlingRightsMask[to]))
{
    int cr = castlingRightsMask[from] | castlingRightsMask[to];
    k ^= Zobrist::castling[st->castlingRights & cr];
    st->castlingRights &= ~cr;
}

Your move representation should be able to tell you what castling move it is, and what castling rights (queen side? king side?) it has. This is implemented in Stockfish as castlingRightsMask[from] | castlingRightsMask[to]. Once you know your rights, you can just add it to your Zobrist key.


Wrongly placed chessboard - what happens? What happens if the chessboard is kept with black square on right hand side instead of white square? I think that the notations will change.
In the new positon, the White king will be positioned on a white square and the Black king will be positioned on a black square. The White queen will be positioned on a black square and the Black queen will be positioned on a white square.
Why this is considered a wrong placing of the chess board? Addtionally, does White or Black have an advantage, and will strategies and tactics change?

It's wrong because the rules say so:

2.1 The chessboard is composed of an 8 x 8 grid of 64 equal squares alternately light (the ‘white’ squares) and dark (the ‘black’ squares).
The chessboard is placed between the players in such a way that the near corner square to the right of the player is white.

Of course, those rules are based on what has been common practice for a very long time. Apparently, an incorrectly placed board happens often enough to warrant a rule for what to do when that happens:

7.2.2     If during a game it is found that the chessboard has been placed contrary to Article 2.1, the game shall continue but the position reached must be transferred to a correctly placed chessboard.

Since the pieces have the same position relative to each other, it doesn't affect strategy and tactics. Notation won't change; the column of the starting positions of the queens is still column 'd'. If you have a board with numbers/letters, it's even easier to spot the problem.


Evaluating Elo rating on a per move basis I've been a Chess.com user for a little over 3 years now. I play EVERY day, usually have anywhere from 10 to 50 games going on any single day.

Since I've started, my rating has only gone up about 150 points. For the past 6 months, my Elo has stayed fairly close to 1400.

I know Chess.com has the feature of evaluating the games that I've played and suggests what I did wrong, but I have to request all of those games to be reviewed.

Is there another tool/app that can evaluate the strength of individual moves during each and every game, that would tell me the "strength" of the move? For example, if I stupidly put my queen in a position where the opponent can take it, then that's a blunder and would be rated very poorly.

Or, is there a way to automate all of the Chess.com games to be reviewed by the engine to determine how I did in each?

Is there another tool/app that can evaluate the strength of individual moves during each and every game, that would tell me the "strength" of the move?

To be able to evaluate the strength of individual moves, one needs to estimate the difficulty level of the position. This estimation rests on two ingredients: the ability to evaluate the position (almost) perfectly, and a sample of responses for that position from a pool of players with different strength. This is thus an empirical question.

For tactical training, there are straightforward implementations, such as this one:

http://chesstempo.com/user-guide/en/tacticRatingSystem.html

You can add to the accuracy of a solution a time element:

http://chess.emrald.net/time.php

For any kind of position, I believe it's still an open problem.

A related question is the optimality of play. To that effect, Guid & Bratko did an interesting study:

  The basis for their evaluation was the difference between the position values resulting from the moves played by the human chess player and the moves chosen as best by the chess program Crafty. They compared the average number of errors in the player's game. Opening moves were excluded, in an attempt to negate the progress in chess opening theory.

http://en.wikipedia.org/wiki/Comparison_of_top_chess_players_throughout_history

But such study cannot estimate the strength of a player as requested by the querent. It can only evaluate optimality of play, and order players according to this evaluation. This does not give ELO or complexity of any given move.


What does "Precision: White = nn%, Black = nn%" mean in a game broadcast by chessbase.com? The game "Salgado L, Iván vs Arroyo R, Jesús, 83rd ESP-ch 1-0", shows this annotation after the last move:

  Precision: White = 93%, Black = 18%.

What does that phrase mean?

Check https://es.chessbase.com/post/sabrina-vega-y-salvador-del-rio-de-angelis-campeones-de-ajedrez-de-espana-2018 for more information.

It surely is a measure of the quality of play, the deviation of the game from a "perfect game", as understood by the engine used in the analysis. A perfect move will lose zero units of measure.

I couldn't find a chessbase source, but here it is a similar question on lichess, in which the unit of measure is called a centipawn:

https://lichess.org/qa/103/what-is-average-centipawn-loss

Centipawn loss could also be expressed as percentage, but as your question is about precision, they should be the opposite amount. In your example for white, a precision of 93% equals 7 centipawn loss (7% of inaccuracy).


How do I keep my bishop pair in this Ruy Lopez line? I am learning Ruy Lopez. And I always play Ruy Lopez opening while I am playing with the white pieces. I recently played the game with Ruy-Lopez and my moves are

[FEN ""]
[StartPly "10"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 b5 5.Bb3 Na5

I want to keep my Bishop pair, but if I play like this then my light-square bishop will be lost in 5 moves. So, what is the best move that I can play to save my bishop pair till the end?

In that position, you can't keep your bishop pair if Black wishes to take your Bishop. Acording to Modern Chess Openings, with this variant Black throws away the White Bishop by ceding the initiative in the center. In the recomended continuations, White has an advantage (+/=) and White must proceed to an inmediate attack:

[Event "Analysis"]
[Site "Ruy Lopez"]
[Date "2020.04.11"]
[Round "?"]
[White "Player"]
[Black "Oponent"]
[Result "*"]
[FEN ""]
[StartPly "10"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 b5 5.Bb3 Na5 6.O-O d6 7.d4 Nxb3
    ( 7...exd4 8.Nxd4 Bb7 9.Bd2 Nxb3 10.Nxb3 Nf6 11.Re1 Be7 12.Na5 Rb8 $14
    {Smagin - Kupreichik, Minsk 1985.} )
8.axb3 f6 9.Nh4 Ne7 10.f4 exd4 $5
    {It is a possible improvement.}
    ( 10...Bb7 11.d5 c6 12.c4 exf4 $14 {Arnason - Agdestein, Gausdal 1987.
    } )
11.Qxd4 Bb7 12.Nc3 $10
    {1/2-1/2(64) Alves, Lair Valio - Petters Merino, Oscar Augusto / CLEA4
    B07 email, CADAP Email 2000.}
*


Upside down diagrams In the good old days when I saw a chess diagram I didn't have to guess which way the pawns were going; there was a convention that the white pawns moved up the board. When and why did upside down diagrams become fashionable? Does it have something to do with playing chess on the internet, or did this foolishness come before the internet?
And why don't they ever rotate the diagram 90 degrees, to give us the kibitzer's view of the board?

Flipped boards are useful when the observer is supposed to control or think as if he were controlling the black pieces. That makes sense because in on-the-board games you play the perspective of white if you're white, but play the perspective of black if you're black, so in the latter case you see a flipped board. It seems pretty reasonable to me.

And why don't they ever rotate the diagram 90 degrees to give us the kibitzer's (spectator's) view of the board?

The most likely reason is that players are simply not as comfortable with that view as with ordinary 0, 180° degrees view (people play more than they watch games).


Studying why Gardner's Minichess Variant is solved? I recently came across an interesting article that proves Gardner's Minichess is solved (2013) and the theoretical result is a draw.

Might studying why Minichess is a theoretical draw help me better understand the concepts behind long term strategy in standard chess?

Here is the starting position of Minichess:

This variant is definitely very interesting, and could prove somewhat beneficial in learning standard chess.

However,

Standard Chess(SC)'s castling operation is not reflected in this variant. Your king is already tucked away.
This variant does not reflect SC pawn structures. Space is too limited.
The value of pieces changes. Knights are going to be worth more than in SC, since they can now traverse half the diagonal of the board in two moves.
No opening knowledge whatsoever will be attained in this variant. Also, common opening motifs from SC (control the center, develop your pieces) will not be used.
Standard tactics from SC will not be used as much in this variant. Skewers and pins, for example, would be quite rare.

That leaves endgame practice, which could be a little helpful, but there's also endgame puzzles in SC - and actual SC endgames in SC.

  Conclusion:

If your goal is to further your understanding of standard chess, you are better off studying standard chess. This variant looks like a lot of fun, but it does not do a good job of teaching typical chess lessons, for reasons outlined above.


French defense plans I'm working with my 1300 USCF kid on his opening repertoire. In the French defense, I have a few questions/problems I'm trying to resolve:

1) In many of the closed lines (after e5) we go after placing a knight on f5. Usually we go at it with ..h5, ..Nh6, ...Nf5.
a) Sometimes people take the knight once it reaches h6 and we recapture with the rook. I struggle for a good plan after that, especially since the rooks are disconnected.
b) When the knight does get to f5 it sometimes gets challenged by the white (light squared) bishop. The question is whether to reinforce this f5 knight with g6 and allow the capture, recapturing with gxf5. We try to play on the open g-file. I haven't been getting good practical results and wonder if I've got this wrong.

2) This question pertains to the advance variation. I've suggested using a quick ..c5, ..Qb6, ..Bd7, ..Bb5 to swap off the bad bishop. In this line we don't have the french Qside pawn storm at first. Moreover,
I've been telling my son that if white breaks the tension with dxc5 we can recapture with ..Bxc5 which I thought was a "French dream".
But recently in this "dream position", I've been hit with b4 and a queenside
pawn storm initiative. Connected with 1a) above I've been getting bad games
(no black queenside pawnstorm, and no Nf5 post). I'm wondering if there's
a simple thing to do to create some black queen side space when the Queen
is out front (perhaps ..a5)?

I would suggest that you look up some theory in the French defense if you're planning on using it. What we seem to have here is a complete home brew.

For example, playing ...h5 before playing ...Nh6 is very uncommon. One of the reasons is that playing h5 as black actually makes Nh6 harder to play for black, as Bxh6  cannot really be answered with gxh6, as the h5 pawn becomes very weak. Thus black is encouraged to play Rxh6, which isn't ideal. If you want to play Nh6 in the advance variation, I suggest you play it without playing h5 first. You do not have to worry much about Bxh6 from white, as that makes b2 harder to defend, and gxh6 doesn't really give black many problems.

More importantly, if you are afraid of playing with the light squared bishop as black in the french, then the opening is not worth playing at all. I think that you may be underestimating the potential of that bishop, if all you want to do with it is trading it. A French player has to be able to play with the light square bishop as black to be successful in the long run. In essence, it's not worth the trouble to trade off the "bad" bishop.


Stockfish - Function that predicts checkmate I'm working on a function that can forecast whether, for a given position, I can be checkmated by the opponent. I have this function, already in Stockfish:

bool Position::is_mate() const {

  MoveStack moves[MAX_MOVES];
  return in_check() && generate<MV_LEGAL>(*this, moves) == moves;
}

This tells me that I am already being checkmated. Ideally, I would like to write a function:

bool Position::is_trap() const {
  for all of the opponent's legal moves
    if move i results in is_mate()
      return true

  return false
}

Both of these functions will be in position.cpp.

Subsequently, I want to generate a list of all legal moves that will result in is_trap() being true (all legal moves that will result in me being checkmated in the next turn). In movegen.cpp I have:

template<>
MoveStack* generate<TRAP>(const Position& pos, MoveStack* mlist) {

  assert(pos.is_ok());
  MoveStack *last, *cur = mlist;
  // Generate all legal moves
  last = generate<MV_LEGAL>(pos, mlist);

  // If a legal move isn't a trap, remove it
  while (cur != last)
    for (i = 0; i = MAX_MOVES; i++)
      pos->do_move(mlist[i].move);
      if (!pos.is_trap())
          cur->move = (--last)->move;
      else
          cur++;
      pos->undo_move(mlist[i].move);

  return last;
}

Is there a more efficient way of doing this? Thank you for your help!

I don't understand why this is an issue. What you're asking is just chess engine search. Nothing more.

Generate all possible moves to a list
Make a move to the position
Search the new position with Stockfish (the search<> function)
Check the returned negamax value if the move leads to forced mate
Undo the move
Get the next move from the list, go back to (2) and repeat


Stop SF MultiPV from returning an upperbound For a given position, I'd like to compute an evaluation of the 3 best moves.
I send this to Stockfish:

setoption name MultiPV value 3
position startpos
go movetime 500.0 // search for 0.5 seconds

I get the following result:

info depth 1 seldepth 1 score cp 84 nodes 71 nps 35500 time 2 multipv 1 pv e2e4
info depth 1 seldepth 1 score cp 80 nodes 71 nps 35500 time 2 multipv 2 pv d2d4
info depth 1 seldepth 1 score cp 72 nodes 71 nps 35500 time 2 multipv 3 pv e2e3
[...]
info depth 13 seldepth 17 score cp 20 nodes 521614 nps 1575873 time 331 multipv 1 pv d2d4 d7d5 b1c3 g8f6 g1f3 e7e6 e2e3 b8c6 f1d3 f8d6 e1g1 e8g8 c1d2 c8d7 c3b5 e6e5
info depth 13 seldepth 17 score cp 20 nodes 521614 nps 1575873 time 331 multipv 2 pv g1f3 d7d5 d2d4 g8f6 b1c3 e7e6 e2e3 b8c6 f1d3 f8d6 e1g1 e8g8 c1d2 c8d7 c3b5 e6e5
info depth 13 seldepth 17 score cp 13 nodes 521614 nps 1575873 time 331 multipv 3 pv e2e4 e7e5 g1e2 b8c6 d2d4 e5d4 e2d4 g8f6 b1c3 f8b4 d4c6 b7c6 e4e5 f6d5
info depth 14 seldepth 18 score cp 15 nodes 771138 nps 1536131 time 502 multipv 1 pv d2d4 d7d5 g1f3 g8f6 e2e3 e7e6 f1d3 b8c6
info depth 14 seldepth 18 score cp 15 nodes 771138 nps 1536131 time 502 multipv 2 pv g1f3 d7d5 d2d4 g8f6 e2e3 e7e6 f1d3 b8c6
info depth 14 seldepth 18 score mate 0 upperbound nodes 771138 nps 1536131 time 502 multipv 3 pv e2e4 e7e5 g1e2 b8c6 d2d4 e5d4 e2d4 g8f6 b1c3 f8b4 d4c6 b7c6 e4e5 f6d5
info nodes 771138 time 502
bestmove d2d4 ponder d7d5

The line info depth 14 seldepth 18 score mate 0 upperbound ... multipv 3 pv e2e4 ... is not useful to me. It indicates that "1.e4" was pruned from the evaluation -- Since it's worse than "1.d4" or "1.Nf3", it was assigned the trivial upper bound of mate 0.

How can I prevent this from happening? I want an evaluation for each of the top 3 moves, not simply an upper/lower bound. One solution is to run another analysis from position startpos e2e4. Is there a simpler way?

You'll need to give the engine more time to think.

Edited

The poster was concern about "upperbound"/"lowerbound" is only returned at the largest depth".

The question makes absolutely no sense. I don't want to get into too much technical details because you need to understand the alpha-beta algorithm. upperbound/lowerbound is NOT something that an end-user ever needs to worry about. It's meant for engine debugging, the information is only and only useful for engine developers. No chess software with a Stockfish engine would tell you anything related to the bounds. Stockfish reports the upperbound/lowerbound information whenever it encounters one for every 3 seconds.

I can't directly answer your question because it is not a valid question. upper and lower bounds are really not something that you should worry.


Variation of chess where winner has to capture all pieces? Is there any variation of chess where the winner has to take all of the opponents pieces rather than just force the capture of one of them ?

I guess sacrifices wouldn't work well in this variation of chess.

First of all, the historical rules of Shatranj include the victory condition "bare King", i.e., capturing all pieces except the King is a victory, except that the other player can capture the last piece of the first player immediately after the loss of his last piece (then, the game is drawn).

As a modern variant, there is Extinction Chess (aka Survival of the Species) where the extinction of one piece type (Knight, Bishop etc.) wins the game.


Can you claim an illegal move in Blitz after pressing your clock (but without making a move)? In Blitz under FIDE rules, Player A makes and completes an illegal move by pressing the clock. Player B states that Player A's move is illegal, does not make a move, but quickly presses his own clock, as if giving Player A the opportunity to correct the move as common in a standard non-Blitz game. Almost immediately, before any other action by either player, Player B realizes that the rules of Blitz apply, stops the clock, and claims the match.

According to Player A, the claim is now "in his time", so is no longer valid. Is this a correct interpretation of the rules?

This is correct. You cannot continue to play (press the clock) and claim a win in blitz. Furthermore in the new rules pressing the clock without making a move counts as an illegal move and so loses (if your opponent claims). This is really just another twist on the old error of taking your opponent's king when he leaves it en prise which again results in you losing for an illegal move instead of your opponent.

In other words, if your opponent makes an illegal move in blitz just claim the game. If you start doing other move-like things (touching a piece, pressing the clock) your claim goes away.

The problem in your case is the same, by the way. An illegal move is only punishable once it is completed by pressing the clock. When you pressed the clock you removed the evidence for the illegal move.


Why is the FIDE name in French? I noticed that FIDE stands for " Fédération Internationale des Échecs". Shouldn't it be in English as 'World Chess Federation'? I noticed, though unrelated, that it is the same for SI Units (System Internationale). Did it start in France? What is the history of the foundings of FIDE?

I noticed that the headquarters is in Athens, Greece. Why? If the International Federation of Chess can't be in English, shouldn't it at least be in Greek? Where did France come in?

In the first half of the XXth century, French and English were the main international languages.

During and immediately after the first congress in Paris, 1924, the French acronym for "Fédération Internationale des Echecs" was actually FIE, and it was referred in the English-speaking world as "International Chess Federation" or ICF. But already the following year, at the Congress in Zurich, French-speaking members (and possibly Italy) made a point that "fide" meant "trust" in Latin, thus the 'D' was added for the name to symbolize the confidence of its members in the institution, and FIDE became the official acronym in both languages (and worldwide).

E.Winter's Chess Notes have a very interesting article about the birth of FIDE:

  ‘FIDE was founded in 1924’ say the history books, yet, technically speaking, that could be disputed. Certainly the Fédération Internationale des Echecs was formed that year, but its Statutes systematically referred to it as ‘FIE’, and not ‘FIDE’:

But it doesn't give the reason of the later change:

  But later in the year, for reasons as yet unclarified, ‘FIDE’ became the official acronym. If ‘FIDE’ appeared in print in 1924, we have yet to find it.

I remember reading that the Latin meaning was the motivation for switching to "FIDE" in some chess-history book in French, but I will have to dig further to source it properly.


Using chess engines to find moves sequence to make a position Is there any way to use chess engines (by commands or GUI tools) to find the sequence of moves need to transform an initial position(P1) to a target position(P2) while the count of moves is exactly N?

For example, after giving it a FEN as P1 and another FEN as P2, it outputs a list of N legal moves that transforms P1 to P2.

Assume it's possible to do N moves to transform the initial position to target position.

Yes and No, but be warned, the possible paths to search through grows exponentially as your N increases.

The short answer is NO, unless you find someone who is doing research on chess and is using an engine for the special case like you are describing.

BUT

If someone were to do research on this special case he would setup his experiment probably like this:

First set an engine to calculate at a fixed depth 1 for the current position and make it return all variants it is evaluating. In effect this will return all possible legal moves from the current position.

All you need to do now is write your own breadth-first search algorithm, set to depth N, that can go from one state to another by using the cofigured engine.


What is the main aim and object of the kings pawn opening? I think that every opening has a particular aim and object.
Can someone tell me the the aim and object of the kings pawn opening?

Generally the goal of the opening is to develop the pieces (knights and bishops in particular) to active squares and to gain space for operation of the pieces (usually achieved by occupying the center with pawns).

If we are talking about the kings pawn opening, i.e. any opening that starts with 1. e4, there is little to say besides:

white aims to occupy the center with a pawn on e4
white makes space for the development of the light squared bishop on f1 (and potentially the queen)

Note that the game after 1.e4 could develop in all kinds of ways of very different character. Many of these openings have their own name (Sicilian, Ruy-Lopez, French, Caro Kann...), their own aims and objectives. Really I'd struggle to call a single move like 1. e4 an "opening".

Also often you will find that proper openings like those mentioned above will be listed by their name while the name King's Pawn Opening is reserved for all the rest, i.e. for games that don't follow any of the established openings.


Beginner Chess Question: Bringing out my queen early? Sometimes I bring my queen out early, however GMs say "Queen is vulnerable to attack and hinders development" I agree with that but most of the time I only bring it to f3 or around the 3rd-rank ex. b3/g3 threatening to take b7 pawn and forking rook and the knight.

Question:
Does it hinder my development if I try to bring it out to the 3rd row. I know it's vulnerable to Knight and Bishop attacks.

Common wisdom is that bringing your Queen out early invites attack and eventually costs you time. And losing time is like giving your opponent free moves. So for players of a certain level, it is true that bringing out the Queen early is not helpful.

That being said, chess is a game between 2 people. It is not between "olde GM lore" and a person.

If you're having fun bring your Queen out early, or if you're winning games by doing it, then keep doing it. If you're playing tournaments, your rating will rise accordingly. By the last rounds you'll be playing the better players in your bracket.

At some point, your opponents will get stronger. You'll notice that an early Queen sortie is a detriment. At that point you'll need to up your game.

Consider not moving your Queen until you have at least 2 other piece off the back row. Getting those pieces 'out of the box' will go a long way towards giving you some good games.


Should any information written on the scoresheet by the players be accurate? The FIDE rules state:

12.4 The scoresheet shall be used only for recording the moves, the times of the clocks, the offers of a draw, and matters relating to a claim and other relevant data.

I believe this rule has been used before, against Wesley So in the 2014 ACP Golden Classic tournament (more here). But, what about this?

This is Carlsen's scoresheet from his game with Alexander Donchenko in the 2018 European Club Cup, where he wrote "Absolutely no shorts allowed" instead of writing his and his opponent's names.
Isn't this a violation of the rules? Why didn't the arbiters take appropriate action?

I believe this rule has been used before, against Wesley So in the 2014 ACP Golden Classic tournament (more here)

Both you and "LuisFSiles" in the chess.com article you quote are wrong. So was warned three times not to write other things on his scoresheet but was not punished (in that case by losing the game by default) for writing unauthorized material on his scoresheet. He was punished for deliberately disobeying the arbiter on three occasions.

Isn't this a violation of the rules?

Yes, it is, albeit a very minor one. The normal approved arbiter action would be to warn the player not to do it again.

Why didn't the arbiters take appropriate action?

Your assumption doesn't make sense. We don't know if the arbiter took action or not.
If the arbiter saw (and paid attention to) the fact that Carlsen had written what he did on his scoresheet then the appropriate action for the arbiter to take would have been to do what the arbiter in the Wesley So case did and give Carlsen a warning. We don't know if that happened or not. In any case. not surprisingly, there was no repeat offence from Carlsen. Carlsen did not wilfully disobey the arbiter even once let alone three times. Hence no reason why the arbiter would take any more obvious action that we would know about like awarding a time penalty.
In this kind of high level tournament the PGNs of the games have to be sent to FIDE. If there are no DGT boards then this transcribing to PGN has to be done by a human but that would not necessarily be the arbiter and it would not necessarily happen the same day. It might even happen after the tournament. In this case I would expect that Carlsen would be playing on a DGT board and so the moves would be recorded electronically. In that case an arbiter might never check the scoresheet and would never know.
What has also to be remembered about the Wesley So case is that it was instigated by an opponent complaining to the arbiter.


Why did Viktor Korchnoi leave the USSR? Why did Viktor Korchnoi/Kortchnoi leave the USSR?

Maybe the answer could include a little more trivia since he is such an interesting character.

The short story is that the Soviet chess authorities at the time were blocking Korchnoi's progress and severely limiting his opportunities to play, as Karpov had been selected as their favorite son. It was the same sort of impediment that Kasparov later faced when he was on his own path toward dethroning Karpov, and it also echoed the scenario from decades before, when it was rumored/suspected that Paul Keres had been forced to take a backseat to Botvinnik.


In Spassky v Fischer '72 game 11, why is 14. Nb1 considered such a great move? In game 11 of the 1972 World Championship, Spassky as white moves his Knight back to its 14. Nb1 starting position. Apparently, this moved was received as 14. Nb1!!. But to me, it seems as a simple attack on the invading black queen to flush her out of the zone.

What about this move makes it so interesting?

Shown below is after move 13. Kh1 Bd7

[FEN "r3kb1r/1p1b1p2/p1nppp1p/8/4PP2/qNN5/P1PQB1PP/R4R1K w - - 0 1"]

Taking a look at the comments in your link, I came across a post quoting GM Edmar Mednis:

  A move which was invariably given two exclamation marks - 14.Nb1!!
  after the game. May I respectfully suggest that if Spassky had
  proceeded to lose this game it would have read 14.Nb1?? If we look at
  the nature of the position, it should be apparent that neither of
  these extremes is warranted. White has difficulties in how to
  continue, so he decides to first kick Black's Queen. However, this is
  an open position and White's QN is placed well on c3. Retreating it to
  b1 obviously cannot be a winning maneuver. It is simply an interesting
  concept, which works because Fischer has an off game. Under the
  circumstances 14.Nd1!? would also have probably won. As a historical
  note, it may be stated that those commentators who were loudest in
  applauding 14.Nb1!? neither played it themselves nor worried about it
  when their turn came.


How does Stockfish calculate advantage? Recently when I was on Lichess, somebody pointed out in chat that Stockfish calculated advantage based on what it considered as the best move for both sides. However, when we play the best moves (moves suggested by Stockfish), the advantage changes, which means that the advantage cannot be solely calculated assuming best moves.

However, the advantage cannot be calculated based on some kind of weighted mean of the possible moves either since Stockfish clearly spots winning strategies such as 'Mate in n' for sufficiently small n.

To make the previous paragraph clear, assume that white has mate in 1, and assume that white has 2 legal moves. Also assume that if white doesn't play the move of checkmate, then black has a forced move that is also mate. In this scenario, if we were taking average, advantage would be zero since random moves would give 50% win chance for white and 50% for black. However, Stockfish would show #1.

So how does Stockfish calculate advantage?

EDIT : This question is not asking how the engine finds the best moves. I am familiar with the decision tree method that engines implement to do so. The question is about the 'advantage' value that the engine evaluates. @SubhanKhan 's comment clarifies why the advantage value changes after performing the best move. Does the engine evaluate advantage solely based on the best moves then?

Good Question! The reason that the evaluation changes when you put in the engine's best moves is because as you do this the computer gets to look deeper into the future. This is the same as if you were thinking for 10 minutes on a position and saw that it was a draw, but when you look for 30 minutes you get to a deeper conclusion realizing that it's actually a draw. Another evidence I have for this is when you let the computer think on a position for a long period of time(say 1 hour) It usually reaches a different evaluation than the initial evaluation. I hope it helps!


Stockfish draw value randomization and "3-fold blindness" In this commit, a change was made to the way Stockfish scores board positions that are draws due to 3-fold repetition or 50-move limits. Prior to this commit, a drawn position was assigned a score of zero; afterwards, it is randomly assigned a score of +/-1 (that is, a tiny non-zero value). In the commit message, the intended result is explained:

  The effect is that in positions with many 3fold draw lines, different
  lines are followed at each iteration. This keeps the search much more dynamic,
  as opposed to being locked to one particular 3fold.

  An example of a position where master suffers from 3fold-blindness and this patch
  solves quickly is the famous TCEC game 53:

  FEN: 3r2k1/pr6/1p3q1p/5R2/3P3p/8/5RP1/3Q2K1 b - - 0 51

  master doesn't see that this is a lost position (draw eval up to depth 50) as
  Qf6-e6 d4-d5 (found by patch at depth 23) leads to a loss.

I don't understand what the change actually accomplishes. Why is visiting drawn positions in different orders helpful? What is meant by "3fold blindness"?

For reference, here's the board position mentioned in the message.

[FEN "3r2k1/pr6/1p3q1p/5R2/3P3p/8/5RP1/3Q2K1 b - - 0 51"]

I would first like to acknowledge that this answer is somewhat speculative; this is the first time I've seen this feature in a a chess engine, and I'd be interested to know what other chess programmers think of my answer.

Contrary to what is commonly believed, (good) chess engines don't just "search all possible moves" up to a certain depth then pick the best one. If we were limited to this, modern engines would only be ~1600. An incredibly, stupidly important idea in chess programming is that of "reductions." There are many different types, but the basic idea is that computers don't search some lines it doesn't consider promising.

Of course, this is a very double edged sword. On the one hand, you get much deeper and more effective searches, but on the other you are destined to miss something. To give you a taste, consider the following position:

[FEN "3n3k/rp4pp/1p5r/pPp1pp2/PpPp1p2/3PpPp1/RN2P1P1/QBNR1BK1 b - - 0 1"]

I'm confident a reasonable player can find the simple mate for black (get both rooks on the h file, and mate on h1, after Ne6 to ensure that White cannot break through), but Stockfish 10 can't find it at "depth 50". This happens because the mate involves like 7 consecutive quiet moves, which Stockfish doesn't see as significant enough to warrant intensive search. (Another example on Lichess.) When engines miss tactics, most of the time something like this is to blame.

One of the most common forms of this technique are "late move reductions," wherein the computer selectively reduces moves found later in the move ordering. (this sorta presupposes you have semi-decent move ordering, but you said you already knew a little of that, so we're skipping it).

Next, iterative deepening. Basically, the idea is that if you ask Stockfish to search at depth 25, it will start by searching depth 1, then depth 2, then depth 3,... then depth 25. This seems like a stupid idea at first, but it has various benefits most of which I won't go into. What's relevant here is that the depth 24 search informs decisions about reductions the depth 25 search makes. So if depth 24 says a move isn't too promising, depth 25 is less likely to search it deeply. (this is a massive simplification).

Ok so what's happening in the commit?

  The effect is that in positions with many 3-fold draw lines, different lines are followed at each iteration. This keeps the search much more dynamic, as opposed to being locked to one particular 3-fold.

Here's how I'm reading this: Before the commit, the computer will be searching the same draws at every iteration. If there are lots of 3-fold lines, it's possible the computer won't search all of them (or at least, all of them deeply). This can lead to "blind spots," where the computer doesn't notice some sideline in a move with a draw score.

Before the commit, each successive iteration would have (roughly) the same blind spots (albeit with more resources to notice the sideline). After the commit, the blind spots are scrambled at each iteration, making it less likely to miss the sideline.

As a toy hypothetical example (which shouldn't be taken too literally): say we have two "draw" moves A and B, both of which are way out at the horizon of the search. Because they are so far away, the computer's evaluation of them is very bad (for several reasons, but for the time being we can just think that only a few of A and B's children are searched due to reductions) so it's possible A and B aren't actually draws.

Now for whatever reason (perhaps reductions), let's say the computer has allocated 5 resources to search the "best" draw move and 3 resources for the "second best" draw move at iteration 24, while allocating 6 and 4 respectively at iteration 25.

Let's also say A is a genuine draw, but B has a sideline which isn't, and will be noticed if it is searched with 5 resources.

Before the commit, if A is searched first at iteration 24, it will likely also be searched first at iteration 25 (meaning the sideline slips through), but after the commit, A and B are equally likely to be searched at each iteration, meaning the sideline is more likely to be found at some iteration, whereupon the computer will take note and correct.

I don't know if that made any sense whatsoever, but I hope it helps.

Again, I'm very open to being corrected here. This is just my reading of the commit.


What's a fun troll bughouse opening? I have been playing e3, Ke2, Kd3 openings in the bughouse chess variation on chess.com.

I got to 1800 pretty easily. I'm looking for other openings to play. As a side note, pushing down a4-a5-a6 is actually pretty strong.

Sacrificing a piece on f7 (via Nf3-g5-f7 or e4, Bc4, Bxf7) creates a hole on f7 which can later be filled by a parachuting piece. This can be quite effective particularly if you have paratroopers ready from your partner's game.


How do I play the Colle System as white? I started playing the Colle system as white about 3 months ago. I have played 9 league games with it and lost every one! The sequence of moves that cause me the most problems is 1.d4 d5 2.Nf3 Nf6 (note that black already has two units hitting
the vital e4 square) 3.e3 Bf5 4.Bd3 Ne4. This might well be a bad move by black, but I have no idea how to play against it. Trying to dislodge the knight with f2-f3 would entail me having to move my f3-knight again and the pawn move would weaken my kingside.The only plan I use at the moment is to play Nbd2, c3 and Qc2 to force black to exchange. But that gets rid of my important d3-bishop and stymies any notion of continuing with a king-side attack.

It would be easier to answer would you show us some of your games where you tried the f3-plan.

5.Ne5 or 5.0-0 aiming for a quick f2-f3 indeed make sense. However, I would argue that the most logical answer is to quit your Colle schemes (after all, Black has a strong grip on e4...) and switch to 5.c4 (or 5.0-0 first, followed by 6.c4)

After 4...Ne4 Black has played twice the same piece and reduced his control of d5. The early development of Bc8 has also left b7 unprotected, which may become a target to a later attack by Qb3.

After the approximative line 5.c4 e6 6.Nc3 (6.Qb3!?, 6.Qc2!?, 6.0-0) c6 7.Qc2 Black cannot maintain his e4-outpost:

7...Bb4 8.0-0

7...Nxc3 8.Bxf5 exf5 9.bxc3 and Black center will collapse to a later cxd5 and c3-c4.

7...Nd6 might be best but Black has lost some time. You can try to exploit this by giving a pawn with 8.Bxf5 Nxf5 9.0-0 followed by e3-e4, or play more conservatively with 8.b3. White must be slightly better.


What are the shogi equivalents of Fool's and Scholar's mate? In western chess, the Fool's mate and Scholar's Mate are two well-known mates that take very few moves from the starting position.  What would be the shogi equivalents to these, or, more generally, what are the fastest checkmates in shogi?

A very fast checkmate (6 moves) is described here:

1. P-7f P-8d 2. P-5f P-5d 3. R-5h S-4b 4. P-5e Px5e 5. Bx5e P-8e 6. Bx7c+ mate

apologies in advance for everyone who feels insulted because of the use of figurines instead of real Shogi pieces - I couldn't find another analysis board


Specialized tactics books to improve position analysis? I know that Mig Greengard used to have the VisualEyes column in Chess Ninja. In that column you were given a position and then a list of moves (say 3 or 4 moves forward) and then you were asked to solve the tactics problem from the position resulting from those moves.

Are there any books or other resources with positions that offer a similar experience?

An example might be like this:

After:

7. Qb3 Qe7
8. Nc3 c6
9. Bg5 b5
10...

White to move and win.

Larry Evans authored "What's the Best Move" in Chess Life for years.  It is what you describe - a position with multiple guess answers.  You're supposed to choose the right one, and say why.

He published a book with the same name.


How many female players participated in the european indivdual championship? The female players, I found out in the european individual championship, are

WGM Aleksandra Goryachkina
 WGM Maria Manakova
 WIM Olga Vasiliev
 WIM Camelia-Adriana Ciobanu

Did any other female players participate ?

You can find the final rankings here to get a list of all participants. You could then check the names against the FIDE ratings website which would tell you the gender of the player.

A quick glance through the list shows these additional female players (probably not exhaustive)

Shlomit Vardi

Limor Altshul

Sophia Toporkova

Michal Lahav


How can I find all games between 2 specific players? How can I find all games played by 2 specific players?

For example: Nigel Short and Magnus Carlsen.

Is there some official FIDE database or something like that?

I'd like an easy way to see things like:

Their overall score against each other
A list of the games that make up this score, each with a link to the PGN of the game, showing date and tournament location etc
Most recent game played

Try http://www.chessgames.com. Just write "Short" and "Carlsen" in the search box.

http://www.chessgames.com/perl/chess.pl?yearcomp=exactly&year=&playercomp=either&pid=&player=short&pid2=&player2=carlsen&movescomp=exactly&moves=&opening=&eco=&result=

EDIT

Response to @Ywapom, Chessgames is quite good for top chess players like Carlsen. However, it can be incomplete for non top players. I'd suggest the expensive Mega Chessbase database.


Why don't we use this scoring system: 2 points for a win, 1 point for a draw, 0 point for a lose? In chess tournaments, when you win you get 1 point, when you draw you get 0.5 point, when you lose you get 0 point.

So we have to use two additional symbols to represent the score of a player: the radix point and the digit "5".
Or sometimes we use three additional symbols: " 1 / 2 ".

My question is: why don't we just multiply everything by 2?
When you win you would get 2 points, when you draw you would get 1 point, when you lose you would get 0 point.

This would simply have the benefit of economizing symbols and making the scores shorter. No more ".5" or "1/2".

Because it's a long-established convention and changing it at this point would be much more trouble than it's worth.

In the words of Gerald Weinberg

  Things are the way they are because they got that way


Does the Chronos GX have a count up setting? I've had the Chronos GX for a while now. However, I don't use it much anymore because I need a count up setting. In other words, I'd like it to start at 0 and have it count up as time is spent.

The regular Chronos has the UP-1 and UP-2 settings. The GX seems to lack those. Or am I missing something?

The GX user manual doesn’t give me much hope.

It appears that the Chronus GX clock does not have a count up mode.

While the normal one does, as you have mentioned, it seems that the GX doesn’t. I found this video on how to set up a count on the normal one. It cites pages 35-36 of the manual on how to do this. As expected, the online PDF of the manual corresponds to the video’s given information.

My conclusion is that if the GX manual does not contain information on how to do it, then it cannot do it. Further evidence of this from this video on how to use GX clock. As far as I can tell, it has no, mention of a count up setting.

So unfortunately the Chronus GX Clock has no count up setting as far as I can tell.


Can a pawn put a king in check? I am only an amateur player, but have been playing for many years. Every now and then I come across people who are adamant that a pawn cannot put a king into check.

The last person who I discussed this with was a high school student who played school competitions and pretty much convinced me. So much so that I have now convinced my father, who taught me how to play over 20 years ago that a pawn cannot check or take another piece to put the king into check.

I've just done a Google search to clarify, although most pages say a pawn can put a king into check it has so many results that it has made me curious:

Where did the idea that a king cannot be put in check by a pawn come from?

Are there are competitions / set of rules / types of games where this rule is enforced in the modern game?

Further question, can a pawn also be moved to put a king into checkmate?

Here's a preliminary answer to where such a belief about chess pawns could possibly have come from. In the Japanese variant Shogi, in which an opponent's captured pieces may be placed onto the board as one's own, it is not legal to place down a pawn that gives immediate checkmate. It's still perfectly legal to drop a pawn that gives check though (and to check/mate normally with a pawn), so this a much less severe restriction than what your question asks about. But this is a case in which the pawns are singled out, because any other piece can be dropped to give an immediate checkmate.

Since Shogi and chess are both believed to derive from Chaturanga, perhaps there is indeed some historical variant in which pawns weren't allowed to check at all; but I'm just speculating at the moment.


good responses to 1. Nf3 So I am a decent player, rated by my estimate at around 1000, even though my actual rating is 5 years and thousands of games out of date. In playing the chess engine in chess free on android, I quickly stopped playing 1. e4 because the center counter/scandinavian became very annoying. I switched to d4, and later to nf3 so that people playing against me wouldn't know how to react (most are sub 1000). I, however, don't know myself what the best response is. The two main lines are 1. Nf3 d5 and 1. Nf3 Nf6. I think that I prefer Nf6 for black, but how should I continue from there? Of course, it depends on what my opponent does, but what should be a position I aim for with black?

Until you reach 14-1500 strength, opening theory is not very important.
One of the best coaches in the world for beginners, National Master Dan Heisman, said:

  It does not matter who gets the advantage out of the opening if one of
  the players is likely to lose a piece to a simple tactic in the
  middlegame. Losing a piece from an advantageous position will almost
  always result in a lost position. So study tactics, not openings,
  until you almost never lose pieces to simple tactical motifs.

However it is good to know the ideas behind opening moves, such as controlling the center, developing, etc.

So 1...Nf6 and 1...d5 are both good moves. They both control the d5 and e4 squares and aid development.


Middle game and endgame principles In the opening, it's helpful for me as a beginner to remember some basic principles: develop your pieces, castle, knights before bishops (generally), don't move the same piece twice, etc. Are there similar, very basic rules of thumb that one can typically adhere to in the middle game and endgame? Or are middlegames and endgames so numerous and distinct that it really depends on the opening, e.g., in $X$, you want to do $y$ and $z$ but in $A$ you want to do $b$ and $c$?

There are quite a lot of basic principles. Whole books have been written on the principles of strategic play, for example. Basis rules are useful and will get you on your way. For more advanced players it is actually more important to understand when to break the rules.

A couple of rules 'off the top of my head':

A knight on the rim is dim, meaning that it's better to keep your
knights centralised than to put them on the edge of the board.
Loose Pieces Drop Off (LPDO), meaning that unprotected pieces are
vulnerable to (double) attack. So keep your pawns and pieces
protecting each other.
The side with less space should exchange pieces (and vice versa).
The side with an advantage should attack, or he risks losing his advantage.
If you have a choice in captures with pawns (say h2xg3 or f2xg3), capture towards the center.
Try to avoid weaknesses in you pawn structure (isolated pawns, doubled pawns,
backward pawns).
Invite everybody to the party, meaning activate all your pieces especially when attacking the enemy king.
Don't make pawn moves on the side of the board where you are weaker.
Etc, etc.

Remember that for every rule above there are a lot of exceptions.

For the endgame:

Activate your king
Improve your position to the maximum
When you have the advantage, try to create a second or third weakness
In rook endings activity (of king and rook) is usually more important than one or two pawns
Opposite colored bishops endings have a large drawing tendency
Knight endings have a lot in common with pawn endings
In queen endings it's more important how far your passed pawn has advanced, than how many passed pawns you have.
Etc, etc.

When studying chess you will gather a lot of these rules.


Does this rook endgame have a name or known original analyst? The position is analyzed in many endgame works, but to my knowledge hasn't been given a name as other similar endgames (e.g. "Vancura's position") have.

Two of the most authoritative works, Nunn (2008) and Dvoretsky (2011), don't give it a name or cite a first analyst.

K7/P4k2/8/8/8/8/4R3/1r6 w - - 0 1

Dvoretsky, M. (2011). Dvoretsky's endgame manual. SCB Distributors.
Nunn, J. (2008). Secrets of rook endings.

I've looked in several books, including Nunn's earlier edition of Secrets of Rook Endings (1992), Muller and Lamprecht's Fundamental Chess Endings, and Silman's Complete Endgame Course.

None of them have give it a name or source, although Silman refers to it as a "Lucena" but notes that it's not a true Lucena, since it's a rook pawn. It does tend to get grouped together with the Lucena and Philidor positions and the bridge and Karstedt maneuvers.


Does ...b5 give Black an advantage? After being squeezed for an entire game I got the chance to ease my position with a pawn exchange. Incidentally, this would open lines for my pieces to attack opponent's weakened king. I played ...b6-b5 in the position below, and won. Computer played badly so I ask here for help to determine objective assessment of the below position -> does ...b6-b5 give equality for Black or can he aim for more?

[Title "Black to move"]
[fen "2r3k1/p4p1p/qp2p1p1/4Q3/2PR1P2/P7/1P4PP/7K b - - 0 1"]

1...b5

EDIT:

To help the viewers understand the nature of this question, here are the lines I saw that convinced me that Black suddenly gets good chances after ...b5 :

[Title "Black to move"]
[fen "2r3k1/p4p1p/qp2p1p1/4Q3/2PR1P2/P7/1P4PP/7K b - - 0 1"]

1...b5 2.c5 (2.Rd7 (2.cxb5? Rc1+) 2...bxc4 3.Qf6 Rf8 4.Qe7 {Trying to win back the pawn} c3! {With the threat of Qf1 checkmate, and cxb2 Black should win in my opinion} ) 2...b4! {Threatening Qf1 checkmate} 3.Qe3 $8 bxa3 4.bxa3 $8 (4.Qxa3? Qf1$) 4...Qf1 5.Qg1 Qxg1+ 6.Kxg1 Rxc5

I think 2.Rd6 was played in the game but I can't remember what happened nor what I had in mind as a response... Since it is clear that after that move Black must defend, my question is answered -> Black can not aim for more than an equality :(

Rd6 followed up with 3. c5 looks strong for White, unless I am missing some obvious tactics.


What is the Bronstein (delay) equivalent of Fischer time control of game in 90 plus 30 second increment for FIDE rating? The FIDE Rating Regulations say

  For a game to be rated each player must have the following minimum
  periods in which to complete all the moves, assuming the game lasts 60
  moves. Where at least one of the players in the game has a rating 2200
  or higher, each player must have a minimum of 120 minutes.

When increments are used this has resulted in the almost standard time control of all moves in 90 minutes with a 30 second increment from move 1. That way each player has 90 minutes plus 30x60 seconds for 60 moves = 2 hours.

If delay is used instead of increments what is the equivalent time control?

It seems to me that game in 90 minutes plus 30 second delay would not satisfy the requirement for a minimum of 120 minutes for 60 moves. Particularly in the opening players will play moves in under 30 seconds as so have less than 120 minutes for 60 moves.

To guarantee 120 minutes playing time for 60 moves and writing all the moves down would require game in 120 minutes plus 30 second delay.

I have seen 40 moves in 100 minutes, then 60 minutes to finish the game plus 30 second delay from move 1 but this is more generous as each player will have a minimum of 160 minutes, not 120 minutes for 60 moves.

That players will typically not use the full extent of the delay is not relevant. The minimum time requirement refers to the least upper bound of the possible amounts of time the players could theoretically take. Thus, G/90 d30 satisfies the requirement, although it is a very uncommon control.


What are the best chess blogs? I enjoy reading about chess and there is a number of blogs that I follow. And I do toy with the idea of starting a chess blog myself in a distant and uncertain future. So I want to tap your combined knowledge:

What are the best chess blogs you know?
What makes them so interesting?

(I know this is the kind of subjective question, stackexchange usually doesn't go for, but I think this could be a very worthwhile collection, possibly as community wiki.)

For players under 1800 USCF/FIDE, Dan Heisman's blog is an extremely helpful source. He has lots of information on:

Thought process: how Hope Chess can cause losses
Time Management: how to manage your time in order to be able to think as much as possible when the game gets complicated.
Practical tips for different situations: when you're way ahead, it's a different game; when you're losing, complicate the position to try to get your opponent to make a mistake; when your opponent is in time pressure, don't blitz him, etc.
Correcting misconceptions: player not recapturing because then he would get doubled pawns (safety is a 100, pawn structure is a 1), players loses because he didn't "see" something when in fact he didn't look out for it (thought process), player making a quick move in a critical position (hand-waving), Player playing a quick move because all moves look bad (acquiescing), Player rejecting move based on shallow or superficial analysis (quiescence error) . . . The list goes on, check out his blog!


Proof of irreversibility of 50 move rule I recently edited the Wikipedia article 50 Move Rule as follows:

  The rationale for this rule is that pawn moves and captures are the
  only '''irreversible''' types of moves.  That is, after each pawn move
  or capture, it is impossible for any previous position in the game to
  be repeated.

Unfortunately, my edit was quickly removed with the comment: This is unreferenced. Come up with a reference if you can.

I think this is pretty clear just by thinking about it, but is there any "formal proof" published anywhere that what I tried to add to the article is true?

EDIT: The words "the only" should be deleted.  In addition to captures and pawn moves, losing the right to castle on either or both sides (by moving a rook or king), or failing to capture a certain pawn "en passant" (thus giving up the right to do so later) are also irreversible.  These logically should also reset the 50-move count but are omitted from the rules for reasons of simplicity.

The two irreversible moves can be proved irreversible (it is impossible to replicate that board state later in the game) like so:

Assumptions:
 - Pawns can't move backward.
 - Every pawn move moves it forward.
 - Pieces can't be added to the board.
 - There is no way to create a pawn (unlike queens, bishops, knights, and rooks which can be created via pawn promotion).

Firstly, captures can be proved irreversible because they always remove a piece from the board. If a board state has N pieces and one is removed you now have N-1 pieces. There is no way to increase the number of pieces so you can never return to N pieces.

Secondly, since every pawn move moves it forward, a pawn can never return to its original position. The only way to have a pawn in that position later on is to have it be occupied by another pawn. But for another pawn to occupy the position that pawn has to move. There is only a finite number of pawns so after every pawn has moved to fill the position left by the previous pawn there are no pawns left to fill the position of the last pawn, preventing the board state from being reached again.


Chess software that can show all legal moves? I'm a casual player, and I learned chess from my Dad when I was a kid, but I still have the problem that I miss really obvious moves I can make (or I don't see really obvious moves the other side can make.)

Is there a chess GUI out there that has a feature that shows all the legal moves possible on the board at a time? Like as arrows pointing from the pieces to squares or something like that?

I believe most sophisticated GUI would have the feature to:

highlight possible moves for any piece; i.e. if you click (or hover) on a piece it will highlight all possible destination squares
highlight attacked pieces
highlight the last move

Arena and chesspad and many others should be able to do this.

Showing all possible moves is not useful as there are far too many in most positions, that you would not see anything anyway.

If you want to play online, also the lichess client (and probably others) can highlight moves.


Why Anand and Carlsen insisted on playing the same opening/defense They played the Berlin defense and Ruy Lopez. Well the question is more like: why Anand insisted to play Ruy Lopez again and again. wouldn't be better if he had tried najdorf and nimzo indian earlier? I felt like Anand is giving Carlen the world championship as a thanksgiving gift! Why would a GM in a world championship be so stubborn. What was he hoping for and what was his plan by insisting to play the same opening?

One of Anand's strengths relative to Carlsen is better opening knowledge, and Anand also had the better analysis team. (UPDATE: According to Carlsen in a recent interview, his team of seconds during the Chennai match consisted of Hammer, Fressinet and Eljanov.) To repeat openings was a natural match strategy for him, trying to turn the match into an opening discussion.

By varying openings, especially with white, Carlsen cleverly avoided most of Anand's preparation. The only set-up that was repeated was d3 against the Berlin (played in two white games by Anand), but Anand couldn't find any weakness there. Anand has played 1.e4 most of his career, and it's understandable that he tried to catch Carlsen there. The one game Anand played 1.d4 he lost, although probably from a strong position.

Yes, Anand should have taken more chances, but even with hindsight it is difficult to devise a  match strategy for him leading to success.


Average income for titled chess players What is the average income for an IM? What about for a super GM? Is there an online site/resource that has these average incomes?

Also only the ones that come from chess or chess-related activities(Sponsorships, Commentary, Tournament Organisation, etc)

This article may answer your question.

If you want it short:

On average, according to Natalia Pogonina (WGM), the top-3 players in the world earn 1 million / year, top 10 - over 200 000$, top 50 - over 100 000$.

If you want more information, try looking around this thread.


FIDE ignores my case. How to proceed? Last year, there was an incident where the arbiter ignored cheating, and I filed a report to register a case to FIDE Ethics Commission. The registration was made by email, in November 2017, and I have the confirmation mail that my request was received.

Although one year passed, no one has contacted me. The case was not even classified as "not admissible" in the website.

I sent them another email asking for the status of my application, and again, no response.

What does this mean? Was my application form somehow invalid and therefore nullified? Should I register another case?

There are several cases where FIDE published a decision, both for national and international tournaments.

How should I proceed?

How should I proceed?

You should get on with your life.

It was a minor incident which you brought to the attention of the arbiter. You disagreed with his decision but did not lodge an appeal with the appeals committee and you did not escalate to the national federation. Instead you went straight to FIDE. They are clearly not wasting time on this and nor should you.


Embedding chess games from PGN in markdown How do I embed chess games from PGN files in markdown format?

Well, on this site, you can use the 'replayer'. Basically, you just paste the PGN as a code block; for more details, see Can we implement a replayer for chess analysis on the site?.

For example, the following code will display the first three moves of the Ruy Lopez opening:

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

(it doesn't work right here because of the <pre> block in the post source)

But this isn't really converting the PGN into Markdown, it's just Stack Exchange's rendering engine detecting the PGN and converting it into a JavaScript widget. There is no 'official' way of converting PGN into Markdown, just like there is no official way to convert it into HTML.


Chess program that will play an opening against me? Is there a chess program that will play a specific opening against me?  The reason being is that I want to practice against the Ruy Lopez, for example and I want a computer to play up to Bb5.  Is there program that can do this, paid or free?

Fritz published by ChessBase can do it for you.

Let's see this tutorial to force Fritz to play specific opening.


How can I teach the endgame to someone who feels it is "boring"? I have a student who is in the 1600-1700 range, who has lost his last few games due to improper handling of endgame positions. Some were drawn, which he lost; some winning which he drew; and some where he could have forced a winning endgame (by simplification) and painlessly won, but instead created further complications (to his credit he won most of those games, but lost the ones thereafter, due to being mentally exhausted) leading to unbalanced, and often uncertain positions.

The cure is obviously to focus on endgame theory, but the problem is, he finds endgame theory boring (as I think many chess players do; in fact, I have this problem myself!). I've been teaching him from Panchenko's "Theory and Practice of Chess Endgames" which I've found is a superb guide to endgame theory, but he doesn't seem to be enjoying it.

When I queried him regarding his disinterest he gave me the following reasons:

He claims he has a poor memory and that endgame theory contains too much memorization (he's partially right, he has a superb ability to remember positions, but not so much move order, which is essential in most theoretical positions)
He cites the old "Before the endgame, the gods have placed the middlegame" addage, saying he can make up for this weakness with better middlegame play (but even he knows he is pushing it, since he's lost several games despite good middlegame play)
He claims endgame study takes too long and does not have immediate results OTB (citing that most of the theoretical positions are ones he has never encountered; this, while true, is ignoring the fact that he avoids the endgame like the plague to begin with)
He just doesn't find endgame study to be exciting (though he has admitted that it is necessary)

I've tried to address these concerns with brute force but I'd like to use a little more finesse in my method.

Many old endgame books are like encyclopedias, they have sections about one type of endgame and then a lot of analysis about all the various situations one might encounter in that endgame. I find those boring and very hard to remember. Let's forget about those.

I can think of three things to mention that might be helpful:

Jeremy Silman's endgame book is organized with chapters based on rating level. His point is that a 1600 player doesn't need to know all the intricacies of the endgame in the way a 2200+ player does. He also has a fun writing style. Maybe concentrating on the first chapters of that book helps.

Also, exercises. Both the Steps Method workbooks and Yusupov's series of books are full of exercises on chess in general, including chapters on various endgames. Challenging exercises are fun to solve and when you finally see how the solution works (usually there's only one way that works), that's memorable.

Thirdly, and probably the most work for the trainer, is to find a good, hard endgame study, and turn that into a whole lesson. I remember a training session I once had with GM Yge Visser (alas, I can't remember the position), where he showed a complicated endgame position. We, the students, could propose some lines but really had no clue.

He then wiped the board and started talking about various building blocks: the K+Q v K+pawn endgame (how it's usually a win, how the a and c pawns can draw, a few exceptions, then lines in which the white king is close enough that he can let black's pawn promote but threaten unpreventable mate on the next move, et cetera). He made this interesting by constantly asking the students, some of them knew some things already, nobody knew everything.

There were other building blocks like this, like the Reti study with the two passed pawns where it seems the black king has no chance to catch the white pawn or help his own promote, but then does it by cleverly keeping both options open.

After two hours or so of this sort of thing, he put the original position back -- and we recognized the main theme, and could suggest relevant moves. As we got a few moves in, it turned out that all those blocks were relevant, and eventually it was a mate in 8 or so, and we found it! "And if you manage to see all this during a game, then you're about GM level."

Although I can't remember the position anymore, I still learned everything I know about K+Q v K+pawn in that session, and it was great fun.

But to find such positions and to turn them into lessons that good takes quite a lot of experience as a trainer, I guess.

In short: don't teach him theory, challenge him with exercises and puzzles.


Position where promotion to bishop is the only move? Let me define the problem clearly so as to avoid confusion. I am trying to find a position where:

The only move is a promotion move.
Said move needs to be promotion to a bishop. Not a queen, not a knight, and not a rook.
Where "only move" means either, a move that draws while all other moves lose, or, a move that wins while all other moves draw or lose.

I have been trying to come up with such a position for more than a week now without success. The following is my thought process.
AFAIK there are two main reasons for underpromoting:

Underpromote to deliver a check/attack that a queen cannot fulfill
Underpromote to avoid stalemate

The first scenario should be irrelevant because a queen has all the moves of a bishop.
For the second scenario, I thought about the fundamental cause of stalemate. Promoting to queen can draw, either due to its rook-move ability, or its bishop-move ability, or both abilities simultaneously.

Reason for stalemate
Rook move
Bishop move
Both

Example FEN
8/k1P5/2P5/K7/8/8/8/8
8/6P1/8/8/8/8/8/k1K5
8/k1P5/8/2K5/8/8/8/8

Solution
Promote to Bishop/Knight
Promote to Rook/Knight
Promote to Rook/Bishop/Knight

As you can see, there is no scenario where you have to get a bishop. Therefore I concluded that any singular reason alone cannot produce a position where promotion to bishop is the only move. In other words, there has to be other conditions in the position that prevent the choice of another piece, in particular that of the knight.
One idea that came to my mind is that you might need a bishop-move to prevent something, but this idea got shot down pretty quickly because if you need to prevent something, that means the opponent is threatening a move, which means there's no stalemate.

Currently, the only semi-plausible idea I have left is that promotion to knight leads to insufficient material, whereas promotion to bishop doesn't. However coming up with such a position is quite difficult as you can imagine (especially given the condition that it has to be the only move), so I have yet to think of one.
Edit:
Thanks to @bof for the solution along this line of thought! It wasn't too difficult after all - I simply overlooked the possibility of promoting with capture, which made it the only move.

I have asked this question to a few IMs and GMs on their streams to no avail (understandably so, since they still have to stream), so I am turning to StackExchange community for ideas and answers. Thank you in advance!

There are numerous chess problems, whether a checkmating one or an endgame study, that feature certain promotions as a necessity to win. Stalemate is the long-known reason behind doing so. Here is a small sampling.
This problem is the first known one to use Bishop promotion, although it is a later correction. Even better it comes with double the fun!
[Titler "Ignazio Calvi  Le Palaméde 4/1836, White Wins (Correction)"]
[FEN "8/6PP/3Pn3/6b1/8/k3P3/p7/K2B4 w - - 0 1"]

1. g8=N! Bxe3 2. h8=B! (2. h8=Q? Nd4 3. Ne7 Nc2+ Bxc2 Bd4+ 5. Qxd4)    Nd4 3. Ne7 Bd2 4. Nd5 {And white wins!}

However, it can also be motivated by the "Dead Position" rule. In the below position, suppose White is down to seconds on the clock. They have no queens or rook nearby and stopping the clock to call in the arbiter might not help really. Thus, White must promote to a bishop, luckily just before the clock runs out. Now, the game is drawn and a half point is saved!
[FEN "8/3P4/8/8/8/7k/7b/7K w - - 0 1"]

1. d8=B


Does Google's new quantum computer mean we will soon have a more powerful AlphaZero? According to a paper published in Nature Google has developed a quantum computer.

  Abstract

  The promise of quantum computers is that certain computational tasks
  might be executed exponentially faster on a quantum processor than on
  a classical processor. A fundamental challenge is to build a
  high-fidelity processor capable of running quantum algorithms in an
  exponentially large computational space. Here we report the use of a
  processor with programmable superconducting qubits to create quantum
  states on 53 qubits, corresponding to a computational state-space of
  dimension 2^53 (about 10^16).

  Measurements from repeated experiments sample the resulting
  probability distribution, which we verify using classical simulations.
  Our Sycamore processor takes about 200 seconds to sample one instance
  of a quantum circuit a million times—our benchmarks currently indicate
  that the equivalent task for a state-of-the-art classical
  supercomputer would take approximately 10,000 years. This dramatic
  increase in speed compared to all known classical algorithms is an
  experimental realization of quantum supremacy for this specific
  computational task, heralding a much-anticipated computing paradigm.

On a cautionary note, Google's central claim, that they have performed in 200 seconds computation that would take current state-of-the-art supercomputers 10,000 years is disputed by IBM in a blog post which claims that:

  We argue that an ideal simulation of the same task can be performed on
  a classical system in 2.5 days and with far greater fidelity. This is
  in fact a conservative, worst-case estimate, and we expect that with
  additional refinements the classical cost of the simulation can be
  further reduced.

3 minutes 20 seconds to perform what would take 2.5 days is still pretty impressive and presumably up-scaling would produce (exponentially) better results.

Note that quantum computing is not so well suited to linear processing, such as would typically be used to generate tablebases, but is ideally suited to highly parallel processes like those used in AlphaZero.

Does this advance mean we can look forward to a vastly improved AlphaZero?

TLDR: No

Reasoning: Quantum Computers in the short to medium term only have some very specific things efficiently (factoring and discrete log and a few others). The algorithm google showed "quantum supremecy" on is basically simulating a random quantum circuit to generate random numbers, which is

about as favorable an algorithm as you could imagine
completely useless as an algorithm since there are plenty of simpler random number generators
probably not even quantum supremecy achieved IBM paper

For general tasks, quantum computers achieve a quadratic speedup assuming a large enough quantum computer (compared to exponential or more speedup for the demonstrated problem). Furthermore, to even run a basic chess evaluation function on a quantum computer you would need at least an order of magnitude more qbits than state of the art (probably way more, but I'm hedging).

Overall, quantum computers now are at about the same stage as computers were in the 1800s. It will be a while before they are useful for anything, and chess is highly unlikely to be something they are ever used for seriously.


Software-based training on Linux 10 years ago I used to learn from an old version of Fritz on DVD. It was great. It had a teaching move while you played full games and it also had automated curriculum to teach you openings, endings, and tactics.

At this point in my life I've fully rejected all Windows and MacOS operating systems in favor of Linux. I'd like to have a chess learning experience like I did with Fritz, though.

I've signed up for Chessbase/Fritz online, but it doesn't seem to have any of the many learning features that I had a decade ago. Do I have any other good options?

I'm looking for a richer learning experience than just an engine analyzing my games post-hoc.

Have you taken a look at lichess.org ? It has a solid web interface, Android/iPhone applications, plenty of chess games/variants, analysis move, there are a few trainings, starting from the basics and ending with pretty advanced stuff, finally there are puzzles taken from the actual chess games, where you have to win the game someone won (or lost) before.