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michael.mcguirk
26-01-2010, 08:43 PM
Perhaps a real version of HAL 9000 would simply announce move 1.e4, with checkmate in, say, 38,484 moves.

I don't know about you, but I haven't seen a game of chess that lasts for 38000 moves...

Desmond
27-01-2010, 08:47 AM
I don't know about you, but I haven't seen a game of chess that lasts for 38000 moves...
Indeed not and I doubt it would be possible to get there without invoking an opportunity to claim a draw by 50 move rule.

16 pawn on the board and if they all make 7 moves that's 112.

32 pieces on the board, say 29 captures (to leave the kings and 1 piece to deliver mate).

Plus the 50 moves at the start of the game.

(112 + 29 + 1) * 50 = 7100 moves.

Kevin Bonham
27-01-2010, 09:38 AM
Indeed not and I doubt it would be possible to get there without invoking an opportunity to claim a draw by 50 move rule.

16 pawn on the board and if they all make 7 moves that's 112.

32 pieces on the board, say 29 captures (to leave the kings and 1 piece to deliver mate).

Plus the 50 moves at the start of the game.

(112 + 29 + 1) * 50 = 7100 moves.

It's a bit more complex than that because some of the pawn moves need to be captures otherwise the pawns can never get past.

Also each pawn moves six times not seven.

Here is something I wrote about this that was published in Bruce Pandolfini's column on Chess Cafe in 2001:

Dear Bruce Pandolfini,

In your column you ask the length of the longest possible game assuming that the 50-move draw rule is used. I have often seen a figure of 5949 moves quoted. That was before King vs King was an automatic immediate draw, but the calculation was also incorrect anyway and I believe (though I'm not absolutely certain) that the longest game is presently drawn with Black's 5898th move. Note that the figure changes with slight changes in the Laws of Chess.

The calculation given by Mc Murray is wrong for two reasons. Firstly while
there can be 96 pawn moves and 30 captures, unless some of those captures
are by (not of!) pawns, then the pawns never get past each other and make
all their moves. It is necessary to have 8 captures by pawns so all the
pawns can pass each other and promote, so the figure to be multiplied is 118
not 126, as 8 of the pawn moves are also captures.

Secondly, while Mc Murray multiplies by 49.5, this is wrong. The game is
drawn only after 50 moves by *both* players without a pawn move or capture, so so long as the side making the pawn move or capture is the same one to make the last pawn move or capture, then that adds 50 moves to the total, not 49.5. So the base figure is 118x50, or 5900.

It's a bit trickier than that because there must be several changes in whose
turn it is to make the pawn move or capture through the game. Assuming
Black makes the first capture, we need a switch to White making the captures so that White can get pieces out and give them up on squares which double White's pawns on files to leave gaps for Black's pawns to pass through. Then we need another change back to Black making these captures. At this stage both sides have unpromoted pawns so we need another switch for White to promote those pawns and take Black's pieces, and a final switch for Black to take White's surviving pieces. Each switch costs half a move, so on Black's 5898th move, a king capture of White's remaining piece, the game is drawn as only two kings are left and FIDE Law 1.3 applies immediately. (Does USCF have this law too?)

To illustrate how to do a 5898 move game, here's an example. Both sides
just move other pieces around in the meantime without triple-repeating:

Black takes White's knights by gxh6 and bxa6 (100 moves)
Black's knights take White's queen and rooks (150 moves)
White plays d3 and e3 (99.5 moves)
White takes four Black pieces with pawns: hxg3, exf4, dxc4,axb3 (200 moves)
White takes Black's other three pieces with bishops (150 moves)
Black takes White's bishops : fxe6, cxd6 (99.5 moves).
White's pawns are on the b,c, f, g files, Black's are on the a, d, e and h
files.
Black makes 44 pawn moves including eight promotions (2200 moves)
White makes 42 pawn moves including eight promotions (2099.5 moves)
White takes Black's eight promoted pieces (400 moves)
Black takes White's eight promoted pieces (399.5 moves)
King vs King, game drawn immediately by FIDE law 1.3

TOTAL 5898 moves

If anyone thinks they can make one go for longer, I would like to see them
construct an outline game like the above to prove it rather than just
supplying an abstract "calculation".

Nobody wrote in disputing the above.

Desmond
27-01-2010, 09:53 AM
Thanks Kevin. I see you thought about this more than I did. :lol:

Capablanca-Fan
29-01-2010, 11:24 AM
Nobody wrote in disputing the above.
Well OK then: to avoid a possible draw claim, double repetition must be avoided.

Jesper Norgaard
03-11-2010, 02:44 PM
I decided to bite the bullet and try and construct the longest possible chess game. A Guinness record intent, perhaps? There are considerable content written on this in the internet, but not much of it very substantiated. In fact there is only one calculation that gets it right. Hats off for Kevin Bonham!

Here are a few links with the wrong results :)
http://blog.chess.com/kurtgodden/the-longest-possible-chess-game
http://www.chess-poster.com/english/notes_and_facts/did_you_know.htm
http://chessobserver.wordpress.com/tag/longest-chess-game/
http://infinityiitd.com/is-chess-an-infinitely-complex-game/
http://www.chesscafe.com/text/bruce22.pdf
http://www.chesscafe.com/text/bruce23.pdf

In retrospect after doing my record attempt, it follows that I lost 6 halfmoves unnecessarily along the way, so the final result was 5895 moves instead of 5898. I only wish i had seen the below cookbook recipe by Kevin Bonham before I started!

I will try to add the two files FIDE_longest_possible_game.pgn (the actual Portable Game Notation file with the moves) and FIDE_longest_possible_game.png (graphics illustrating the handling with BabasChess and Waxman).

I quickly found out that there were few programs actually supporting such long games. Chessbase comments out all moves after move 300. SCID parses all 5895 moves correctly but then hangs and must be aborted. I probably tried a dozen programs (including web applets) but only BabasChess lived up to the promise of both editing and showing all moves, while making it possible to jump to given move numbers.
Waxman was useful because it allows for checking casual 3-times repetition of a position underway and 50-moves rule, so it helps eliminate mistakes in the move order, but also claims draw with (=) in the move list while allowing for continuation of the game. Waxman did have a small caveat, it would claim a draw after promotion thus not considering that this is another pawn move which zerosets the 50-move counter!

In essence this post from Kevin outlines the below

Here is something I wrote about this that was published in Bruce Pandolfini's column from Chess Cafe in 2001:

Dear Bruce Pandolfini,

In your column you ask the length of the longest possible game assuming that the 50-move draw rule is used. I have often seen a figure of 5949 moves quoted. That was before King vs King was an automatic immediate draw, but the calculation was also incorrect anyway and I believe (though I'm not absolutely certain) that the longest game is presently drawn with Black's 5898th move. Note that the figure changes with slight changes in the Laws of Chess.

The calculation given by Mc Murray is wrong for two reasons. Firstly while
there can be 96 pawn moves and 30 captures, unless some of those captures
are by (not of!) pawns, then the pawns never get past each other and make
all their moves. It is necessary to have 8 captures by pawns so all the
pawns can pass each other and promote, so the figure to be multiplied is 118
not 126, as 8 of the pawn moves are also captures.

Secondly, while Mc Murray multiplies by 49.5, this is wrong. The game is
drawn only after 50 moves by *both* players without a pawn move or capture, so so long as the side making the pawn move or capture is the same one to make the last pawn move or capture, then that adds 50 moves to the total, not 49.5. So the base figure is 118x50, or 5900.

It's a bit trickier than that because there must be several changes in whose
turn it is to make the pawn move or capture through the game. Assuming
Black makes the first capture, we need a switch to White making the captures so that White can get pieces out and give them up on squares which double White's pawns on files to leave gaps for Black's pawns to pass through. Then we need another change back to Black making these captures. At this stage both sides have unpromoted pawns so we need another switch for White to promote those pawns and take Black's pieces, and a final switch for Black to take White's surviving pieces. Each switch costs half a move, so on Black's 5898th move, a king capture of White's remaining piece, the game is drawn as only two kings are left and FIDE Law 1.3 applies immediately. (Does USCF have this law too?)

To illustrate how to do a 5898 move game, here's an example. Both sides
just move other pieces around in the meantime without triple-repeating:

Black takes White's knights by gxh6 and bxa6 (100 moves)
Black's knights take White's queen and rooks (150 moves)
White plays d3 and e3 (99.5 moves)
White takes four Black pieces with pawns: hxg3, exf4, dxc4,axb3 (200 moves)
White takes Black's other three pieces with bishops (150 moves)
Black takes White's bishops : fxe6, cxd6 (99.5 moves).
White's pawns are on the b,c, f, g files, Black's are on the a, d, e and h
files.
Black makes 44 pawn moves including eight promotions (2200 moves)
White makes 42 pawn moves including eight promotions (2099.5 moves)
White takes Black's eight promoted pieces (400 moves)
Black takes White's eight promoted pieces (399.5 moves)
King vs King, game drawn immediately by FIDE law 1.3

TOTAL 5898 moves

If anyone thinks they can make one go for longer, I would like to see them
construct an outline game like the above to prove it rather than just
supplying an abstract "calculation".

Nobody wrote in disputing the above.

I will only dispute 2 small things. First the above calculation is correct in claiming a base figure of 118x50 = 5,900 only because of the pecularity that first 50 moves can be made, then 118 times the life of the game is prolonged with 50 moves by moving a pawn or capturing a piece, however the last time this is done the count stops *before* the next 50 moves because with bare kings it is an instant draw. I am sure you made the right thinking but it is not so clear that the first free 50 moves are matched by the last 50 moves that can't be moved with bare kings.

Secondly the sequence you presented

Black makes 44 pawn moves including eight promotions (2200 moves)
White makes 42 pawn moves including eight promotions (2099.5 moves)
White takes Black's eight promoted pieces (400 moves)

Here I see a problem, although it is not clear to me if it is or not, of maintaining two kings out of check, and still have enough room to make 50 moves for each pawn move without repeating the position, while still shuffling around those eventually 16 queens. I would say there is some technical difficulty in that, while not claiming it is impossible. But consider the following rearrangement:

Black makes 44 pawn moves including eight promotions (2200 moves)
White takes Black's eight promoted pieces (400 moves)
White makes 42 pawn moves including eight promotions (2099.5 moves)

Now it's much easier! Before white attempts to queen, he gobbles up all the black queens, but losing no halfmoves with this rearrangement.
I conclude that the longest possible game is in fact possible as above, with the last moves e.g. 5898. Qh1+ Kxh1 ½-½
Here is my outline based on the above:

Black takes White's knights by gxh6 and bxa6 (50.Nh6 gxh6 ... 100.Na6 bxa6)
Black's knights take White's queen and rooks (150...Nxd1 200...Nxh1 250...Nxa1) [1.halfmove lost from here]
White plays d3 and e3 (300.d3 350.e3)
White takes four Black pieces with pawns: hxg3, exf4, dxc4,axb3 (400.hxg3 450.exf4 500.dxc4 550.axb4)
White takes Black's other three pieces with bishops (600.Bxa8 650.Bxh8 700.Bxa8 after Qa8 for instance) [1. halfmove lost from here]
Black takes White's bishops : fxe6, cxd6 (749.Be6 fxe6 799.Bd6 cxd6).
White's pawns are on the b,c, f, g files, Black's are on the a, d, e and h files.
Black makes 44 pawn moves including eight promotions (849...a5 ... 3049...h1Q) [1. halfmove lost from here]
White takes Black's eight promoted pieces (3098...Qd4+ 3099.Kxd4 3149.Kxd4 3199.Kxd4 ... 3499.Kxd4)
White makes 42 pawn moves including eight promotions (3549.f5 ... 5599.g8Q) [1. halfmove lost from here]
Black takes White's eight promoted pieces (5648.Qd8+ Kxd8 5698.Qd8+ Kxd8 ... 5898.Qd8+ Kxd8 ½-½)
King vs King, game drawn immediately by FIDE law 1.3

But now that I have seen how this can be done, I am probably too lazy to produce the game. After all it is quite a lot of nitty-gritty.
Half the challenge was also to show it work in real life, my PGN file should be an indication of the feasibility of the method.

- Jesper Nørgaard Welen, 2010-11-02

Kevin Bonham
03-11-2010, 04:21 PM
http://ficsforum.110mb.com/ficsforum/viewtopic.php?f=14&t=8 has the right answer too and for the right basic reasons (though I haven't tried to verify or refute the suggested method) and is the only other one I can find in English that has it right without quoting my solution. It's amazing how many wrong answers there are; I've seen a few in books and they were all wrong too.

But consider the following rearrangement:

Black makes 44 pawn moves including eight promotions (2200 moves)
White takes Black's eight promoted pieces (400 moves)
White makes 42 pawn moves including eight promotions (2099.5 moves)

I'm confident my method is safe and that it would be quite easy to keep the promoted pieces in a bunch somewhere and thus avoid checks, but I agree that yours is more obviously safe and therefore better.

Jesper Norgaard
03-11-2010, 06:02 PM
http://ficsforum.110mb.com/ficsforum/viewtopic.php?f=14&t=8 has the right answer too and for the right basic reasons (though I haven't tried to verify or refute the suggested method) and is the only other one I can find in English that has it right without quoting my solution.
That piece of analysis was utterly unconvincing to me. Especially the reasons why switching turns between white making draw-avoiding moves and black making them, seemed cloudy arguments to me. Your cookbook recipe was much easier to proof watertight.

I'm confident my method is safe and that it would be quite easy to keep the promoted pieces in a bunch somewhere and thus avoid checks, but I agree that yours is more obviously safe and therefore better.
I now realize I was obsessed with queening - but underpromoting for instance to knights this becomes child play. The only requirement is that the last piece is at least a rook, or else a "dead" position occurs before the last knight or last bishop is taken. So say 15 knights and a white rook, that would be pretty easy. The rook finishes the ball, eaten by the black king.

If insisting on queens the problem of lack of room to make maneuvers for wasting time beetween the 50-moves cycles seem to me to become quite big, since any little rotation of either king or queens will repeat the position too fast. If white could just move positively each move like 1.b4 and 2.b5 and 3.b6 then it would be rather straight-forward, but because both players need to shuffle too for 50 moves between each pawn push, I would really like to see a cookbook recipe on that!

By the way, is Babaschess really the only PGN reader that reads the damn game? I have tried Rybka, Keith Fuller pgn-reader, Chesspad, Chessdb, SCID, PGN Mentor, etc. etc. It occurs to me that it would be impossible in all of these programs to see the famous mate in 524 moves (7-piece position counting kings) in a PGN file, or even proprietary game file for that matter.

Desmond
04-11-2010, 11:01 AM
If you two ever meet OTB you should play it out. :)

Kevin Bonham
04-11-2010, 12:37 PM
If you two ever meet OTB you should play it out. :)

With clocks and increment. :lol:

Jesper Norgaard
04-11-2010, 05:41 PM
He, he, Boris. Good one. But I have my secret weapon, I will make Kevin dizzy with 15 knights on board - think of all the knight forks! It's not every day you can claim a family check to a king and 7 knights with one single move!

antichrist
04-11-2010, 10:31 PM
longest games, is every possible position taken to repetition 2 times?

Kevin Bonham
04-11-2010, 10:35 PM
longest games, is every possible position taken to repetition 2 times?

There isn't time to try that because the 50-move rule gets in the way. Without the 50-move rule the longest possible game would be incredibly long. You might have the same 118 phases but the number of moves in each phase would be enormous.

Kevin Bonham
04-11-2010, 10:52 PM
It's not every day you can claim a family check to a king and 7 knights with one single move!

I've moved the task I came up with in response to this (find the greatest number of pieces you can place under attack with a single move) to its own thread here. (http://chesschat.org/showthread.php?t=12554)

antichrist
04-11-2010, 10:59 PM
There isn't time to try that because the 50-move rule gets in the way. Without the 50-move rule the longest possible game would be incredibly long. You might have the same 118 phases but the number of moves in each phase would be enormous.

But where repetition is possible just short of incurring 50 move rule has it been applied?

Kevin Bonham
04-11-2010, 11:13 PM
But where repetition is possible just short of incurring 50 move rule has it been applied?

It doesn't really matter because in most cases you can easily use up the 50 moves without even getting the same position twice let alone three times.

Jesper Norgaard
05-11-2010, 06:43 AM
But where repetition is possible just short of incurring 50 move rule has it been applied?

Actually it happened to me a couple of times while shuffling around pieces to wait for the 50 move break, but Waxman catched it for me, and allowed me to redo for a supposedly "clean" PGN file with no accidental repetitions. I used FindDraw made by a german to check the whole PGN file for draws, but it aborted without giving any result. Does anybody know of such an utility that actually works? Alternatively a chess db or chess program that can import a game and then check it for draws?

Kevin Bonham
30-05-2015, 09:39 PM
*bump*

Discovered that a poster on chess.com, falconbrook, has trumped my 5898 move solution for the longest possible chess game (from 2001) with a 5898.5 move solution (ie game ends with white's 5899th move).

Here is falconbrook's solution (from thread at http://www.chess.com/forum/view/general/i-have-calculated-the-longest-possible-chess-game?page=4)

I have also been thinking about the longest possible chess game recently, when I came upon this thread. I came to a similar answer as those of you that claim the longest game, limited by the 50-move rule, is 5898 moves. But I claim that the longest game is actually 5898.5 moves, ending with one final move by white.

Where my logic differs is that I claim the game can be played with only 3 switches in the responsibility of which player moves pawns and captures, whereas many posts here have claimed that it requires 4. Some of the posts here seem to indicate that each team must capture with pawns 4 times, for a total of 8 pawn captures. I claim that while 8 pawn captures total must occur, they need not be split equally in order to maximize the total number of moves that are either pawn moves or captures. The example I'll give involves black making only 2 pawn captures, while white makes the other 6, though there are other ways to do it with only 3 switches in responsibility.

On the 50th move, black takes the responsibility for pawn moves and captures. He captures two white knights with the two pawns that started in front of his bishops, as only the white knights can get out before white moves any pawns. Note that white can also move rooks back and forth into the empty knight spots, if needed when both knights are captured. Black will also need to advance both pawns that started in front of knights, such that they're ahead of his pawns that started in front of rooks.

The first switch occurs now, and white takes the responsibility. White must make 6 pawn captures and advance all 8 pawns to promotion during this period. The pawns from in front the the knights capture inward, to move into the files of the bishop. The pawns from in front of the king and queen capture outward, into the files of the bishop as well. 6 white pawns can now advance to promotion up the bishop files. The white pawns in front the the rooks advance to the rank of the black pawns from the knights file and capture pieces inward, into the knight files. Since the black pawns from the knight files had advanced beyond the black pawns from the rook files during black's first responsibility, the white pawns that have now captured into the knights file are past the black pawns from the same file, allowing these last two white pawns to continue advancing the rest of the way to promotion. Note that 6 of 7 black pieces were captured, leaving black with a king, another piece, and 8 pawns.

The responsibility now switches a second time, back to black. Black promotes all 8 pawns, with no white pawns left to block them, and captures all of white's pieces except the white king.

The responsibility switches a third and final time, back to white. White's king captures all of black's remaining pieces except the king. On the final capture of a black piece by the white king, the game ends in a draw due to insufficient material for checkmate with the king vs king endgame. White makes this final move, ending the game at 5898.5 moves.

On a somewhat different note, the longest game does not have to end in a draw, as some posts seemed in imply. We could end with white achieving checkmate on the final move. During black's second responsibility, he could have captured all of white's pieces except the king and a queen (or rook). Then during white's final responsibility, after white captures all of black's pieces except the king with his king and queen, the game does not end. We instead go an additional 50 moves with white king and queen vs black king. These 50 extra moves exactly compensate for the 50 moves lost by black not taking white's last queen. White has the final move, and the game will end at 5898.5 moves, regardless of what move white makes here. White can choose to checkmate black using the queen on this final move.

Note that this checkmate on the final move was also possible with the four switch scheme described in earlier posts, with black remaining a queen (or rook) and achieving checkmate on the final move, ending at 5898 moves.

Well done falconbrook!

(For clarification: falconbrook's answer involves the black bishop pawns capturing inwards, onto the d and e files.)

paulo101977
23-06-2020, 03:58 AM
I don't know about you, but I haven't seen a game of chess that lasts for 38000 moves...

Well, HAL 9000 is a fictional movie computer. I do not know if there is any game so long noted and there would be no way to reach such a large number of plays without a draw or victory in a previous move.