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Give a legal position which is "dead" but would take (assuming the §5.2.2 about dead positions wouldn't exist) maximally long to play out until an automatic draw by fivefold, 75 moves or statemate results.

[FEN "5b1k/4p1pB/4PbP1/8/8/8/8/7K w KQkq - 0 1"]

This is a non-example (in a help-game e7 can be taken eventually) so the obvious idea adding more bishops doesn't work!

Hauke Reddmann
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    How is this a legal position? – Brian Towers Feb 01 '22 at 11:29
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    @BrianTowers It is a legal position, but unlikely to occur in a real game, as both players would have to cooperate to reach it. Black has never moved his bishop from the starting square and promoted a pawn to another bishop of the same colour (a or c-pawn). Whites bishop got into h7 after Blacks King went to h8 and after that, Black shuffled his bishop while White advanced his pawns to e6 and g6. – Hauptideal Feb 01 '22 at 13:07
  • I like the term "death certificate" – Laska Apr 11 '22 at 08:45

1 Answers1

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Here is such a position.

[FEN "1k6/p1p1p1p1/P1P1P1P1/8/8/8/PKP1P1P1/8 b - - 0 1"] 
[startlfipped ""]

With Black to move, no side can make any progress. White still has plenty of pawn moves to make to reset the 75 move counter. It's a legal position as well.

Interestingly, this is a position that humans understand better than engines! It's a draw, even if Stockfish insists it's +7.

EDIT:

As pointed out in the comments, adding 4 black pawns that White can take adds another 12 resets to the 50 (75 if unclaimed) move counter.

Also, a wBh7 that cannot escape and will eventually be taken would add yet one more reset but this is not possible since this bishop never could escape f1 to get there.

[FEN "kR6/p1p1p1p1/P1P1P1P1/p1p1p1p1/8/8/PKP1P1P1/8 b - - 0 1"] 
[startlfipped ""]
Evargalo
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Hauptideal
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    I guess that's a record - a useless bishop only gives +50 moves once, when it is captured. The pawns give 4x50. – Hauke Reddmann Feb 01 '22 at 20:22
  • No, they give much more than that. They give 75 moves (50 if claimed) each time they are moved, and there are 12 pawn moves. Which would amount to hundreds of moves in any case. – Hauptideal Feb 01 '22 at 21:00
  • Sorry, I wrote too obscure, I meant 50 per pawn move (as you said). BTW, three columns give only 2+2+2+2+3=11 pawn moves. – Hauke Reddmann Feb 02 '22 at 16:11
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    Note added in browsing through old MatPlusForum threads: Add black Pg5 Pe5 Pc5 Pa5. Still dead, but White can capture the straddlers and *then* run own pawns. (2b+1capture+3w)*4*50 doubles the record :-) http://matplus.net/start.php?px=1644252648&app=forum&act=posts&fid=gen&tid=389 I even participated in that thread, shame on me :-) – Hauke Reddmann Feb 07 '22 at 17:08
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    that's right, very good idea! I also thought about whether Black should start on a8, with the only move to capture a piece on b8 in order to make sure the move counter is reset. I will edit the answer accordingly. – Hauptideal Feb 08 '22 at 00:00
  • @Hauptideal but the position with the knight is not dead, right? – wimi Feb 08 '22 at 21:38
  • you're right, it needs to be a rook so that Blacks only legal move is to capture it. I didn't notice that once we add black pawns, they can move, too. Thanks for the note, I have edited the position accordingly. – Hauptideal Feb 09 '22 at 19:18
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    @Hauptideal: going through old MatPlusForum posts again, I had an idea: +wBh7! It can't get out and adds another 50 moves when captured. – Hauke Reddmann Apr 06 '22 at 08:06
  • I think this record cannot be beaten. Black must make the first capturing move. So 25*75.0 = 1875.0 moves – Laska Apr 11 '22 at 09:03
  • @HaukeReddmann I already updated the answer, when I noticed that your suggestion leads to an illegal/impossible position. The reason is, that all pawns on White still are on their starting squares. Thus, the bishop can not have gotten out from its starting square. This would be true even for chess960. Also, White can not have promoted a pawn to a bihsop, as all White pawns are still present. It may be possible to replace a pawn with the bishop but that does not change the max number of moves to be played. White's bishop in this position has been captured on its starting square. – Hauptideal Apr 12 '22 at 15:17
  • @Hauptideal: (slaps himself with trout) You are correct, of course. And all mirroring or shifting or a Bf1 ruins the deadness. It shows I'm no retro guy... – Hauke Reddmann Apr 12 '22 at 16:06