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zullil wrote:

jdart wrote:from the blitz event today after CCT-16:

[D] 8/8/1p3kp1/p1pP1r1p/P1P5/1P2R1P1/4K3/8 b - -

bm Kf7. Re5 is wrong: many engines think it is a draw, at least at first, but it is not.

Stockfish 4 got the right idea here after about a minute on my quad.

--Jon

Latest Stockfish suggests that Kf7 draws:

Code: Select all

info depth 62 seldepth 91 score cp -12 nodes 537639176745 nps 25109854 time 21411481 multipv 1 pv f6f7 e3e6 f5f6 e6e5 f6d6 e5e4 g6g5 e2e3 d6f6 e4e5 f7g6 e5e8 g6g7 e3d3 f6f2 e8e6 f2f1 d3e2 f1f6 e6e8 g7f7 e8h8 f7g6 e2e3 f6f7 h8b8 f7e7 e3f3 e7f7 f3g2 f7f6 b8h8 f6f7 h8e8 g6f5 g2h3 f7f6 e8g8 f6h6 g8b8 h6d6 b8f8 f5g6 h3g2 d6f6 f8b8 g6f5

info depth 63 currmove f6f7 currmovenumber 1
info depth 63 currmove f5e5 currmovenumber 2
info depth 63 seldepth 91 score cp -12 nodes 658304168640 nps 25336583 time 25982357 multipv 1 pv f6f7 e3e6 f5f6 e6e5 f6d6 e5e4 g6g5 e2e3 d6f6 e4e5 f7g6 e5e8 g6g7 e3d3 f6f2 e8e6 f2f1 d3e2 f1f6 e6e8 g7f7 e8h8 f7g6 e2e3 f6f7 h8b8 f7e7 e3f3 e7f7 f3g2 f7f6 b8h8 f6f7 h8e8 g6f5 g2h3 f7f6 e8g8 f6h6 g8b8 h6d6 b8f8 f5g6 h3g2

info depth 64 currmove f6f7 currmovenumber 1
info depth 64 currmove f5e5 currmovenumber 2
info depth 64 seldepth 91 score cp -12 nodes 697200610476 nps 25346381 time 27506909 multipv 1 pv f6f7 e3e6 f5f6 e6e5 f6d6 e5e4 g6g5 e2e3 d6f6 e4e5 f7g6 e5e8 g6g7 e3d3 f6f2 e8e6 f2f1 d3e2 f1f6 e6e8 g7f7 e8h8 f7g6 e2e3 f6f7 h8b8 f7e7 e3f3 e7f7 f3g2 f7f6 b8h8 f6f7 h8e8 g6f5

beachknight wrote:SF PA_GTB DD agrees:

mvk wrote:

beachknight wrote:SF PA_GTB DD agrees:

In this case you would have to show that the engine understands that Re5 loses. Showing that it prefers Kf7 doesn't mean a lot. That could be coincidence.

Bonus question: are there situations where zugzwang is NOT mutual? I have always been stumped by that 'mutual' attribute. Chess players seem passionate about the difference, but never come up with a convincing example of zugzwang that isn't mutual.

mvk wrote:Bonus question: are there situations where zugzwang is NOT mutual? I have always been stumped by that 'mutual' attribute. Chess players seem passionate about the difference, but never come up with a convincing example of zugzwang that isn't mutual.

There are three types of chess positions:

• 1. both sides would benefit if it were their turn to move
  2. only one player would be at a disadvantage if it were his turn to move
  3. both players would be at a disadvantage if it were their turn to move.

mvk wrote:

beachknight wrote:SF PA_GTB DD agrees:

In this case you would have to show that the engine understands that Re5 loses. Showing that it prefers Kf7 doesn't mean a lot. That could be coincidence.

go infinite searchmoves f5e5

info depth 50 seldepth 67 score cp -7707 nodes 1001178252 nps 11520508 time 86904 multipv 1 pv f5e5 e3e5 f6e5 e2e3 e5f5 e3f3 g6g5 g3g4 h5g4 f3g3 f5f6 g3g4 f6g6 d5d6 g6f7 g4g5 f7e6 g5g6 e6d6 g6f6 d6d7 f6f7 d7c6 f7e6 c6c7 e6e7 c7b7 e7d6 b7a6 d6c6 a6a7 c6c7 a7a6 c7b8 b6b5 a4b5 a6b6 b8c8 a5a4 b3a4 b6a5 c8c7 a5b4 b5b6 b4c4 b6b7 c4d3 b7b8q c5c4 b8b5 d3c3 b5c4 c3c4 c7b6