Test position -strategic

[MikeGL]

[d]8/5p2/8/8/p7/rpK4p/1p3ppr/bQ1N1bqk w - - 0 1

Quite easy for humans, but it seems engines don't find the right plan.

The idea ofcourse is to put black into zugzwang, by white king triangulation.
Only problem with K-triangulation is that the wK cannot step on white-squares due to delivery of check by B followed by QxN and black wins.

So the only square for safe triangulation is a8.
Hence 1. Kb4 Ra2 2. Ka5 Ra3 3. Kb6 Ra2 4. Ka7 Ra3 5. Kb8 Ra2 6. Ka8 Ra3 7. Ka7 Ra2 8. Kb6 Ra3 9. Ka5 Ra2 10. Kb4 f6 11. Ka5 Ra3 12. Kb6 Ra2 13. Ka7 Ra3 14. Ka8 Ra2 15. Kb8 Ra3 16. Ka7 Ra2 17. Kb6 Ra3 18. Ka5 Ra2 19. Kb4 f5 * +-

White continues the a8-maneuver until black is forced to play the f1-B and white delivers mate with Nxf2#.

[LaurenceChen]

Why is Black forced to move the f-pawn? Couldn't Black just repeat the position 3 times by simply moving the rook back and forth from a2 to a3 and a3 to a2?
Do not see the forced win for White.

[MikeGL]

After the wK performs triangulation at a8 and returns to b4, the R cannot play Ra3 because of Kxa3, and it will be a faster mate this time because black's all other moves will be the f-pawn when the R is gone. There will be no need for a8 maneuver if Rook is gone.

Position is a forced mate in 47.

[lech]

[d]8/5p2/8/8/p7/rpK4p/1p3ppr/bQ1N1bqk w - - 0 1

Quite easy for humans, but it seems engines don't find the right plan.

The idea ofcourse is to put black into zugzwang, by white king triangulation.
Only problem with K-triangulation is that the wK cannot step on white-squares due to delivery of check by B followed by QxN and black wins.

So the only square for safe triangulation is a8.
Hence 1. Kb4 Ra2 2. Ka5 Ra3 3. Kb6 Ra2 4. Ka7 Ra3 5. Kb8 Ra2 6. Ka8 Ra3 7. Ka7 Ra2 8. Kb6 Ra3 9. Ka5 Ra2 10. Kb4 f6 11. Ka5 Ra3 12. Kb6 Ra2 13. Ka7 Ra3 14. Ka8 Ra2 15. Kb8 Ra3 16. Ka7 Ra2 17. Kb6 Ra3 18. Ka5 Ra2 19. Kb4 f5 * +-

White continues the a8-maneuver until black is forced to play the f1-B and white delivers mate with Nxf2#.

In our brains there is only software (better or worse);
The human right plan aroses by alpha-beta search like in engines.
I try to prove it.

Look, Sting-sf-3 needs 23 seconds (dual core) to solve it (find the right plan) !!!

[d]8/5p2/8/8/p7/rpK4p/1p3ppr/bQ1N1bqk w - - bm Kb4(d4);

Code: Select all

info depth 47 seldepth 17 multipv 1 score cp 0 nodes 11740929 nps 686242 time 17
109 pv c3d2 f7f6 d2e3 f6f5 e3f4 a3a2 f4e3 a2a3
info depth 48
info currmove c3d2 currmovenumber 1
info nodes 13442174 nps 702307 time 19140
info currmove d1b2 currmovenumber 2
info currmove c3d4 currmovenumber 3
info currmove c3b4 currmovenumber 4
info depth 48 seldepth 0 multipv 1 score cp 8 lowerbound nodes 16279024 nps 6941
12 time 23453 pv c3b4 a3a2 b4a5 a2a3 a5b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a2a3 b8a
7 a3a2 a7b6 a2a3 b6c5 a3a2 c5d4 a2a3 d4c3 f7f6 c3d4 a3a2 d4c5 a2a3 c5d6 a3a2 d6c
7 a2a3 c7b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a4a3 b8c7
info nodes 16279024 nps 693639 time 23469
info currmove c3b4 currmovenumber 1
info depth 48 seldepth 0 multipv 1 score cp 16 lowerbound nodes 16279526 nps 693
660 time 23469 pv c3b4 a3a2 b4a5 a2a3 a5b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a2a3 b8
a7 a3a2 a7b6 a2a3 b6c5 a3a2 c5d4 a2a3 d4c3 f7f6 c3d4 a3a2 d4c5 a2a3 c5d6 a3a2 d6
c7 a2a3 c7b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a4a3 b8c7
info currmove c3b4 currmovenumber 1
info depth 48 seldepth 0 multipv 1 score cp 28 lowerbound nodes 16279932 nps 693
235 time 23484 pv c3b4 a3a2 b4a5 a2a3 a5b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a2a3 b8
a7 a3a2 a7b6 a2a3 b6c5 a3a2 c5d4 a2a3 d4c3 f7f6 c3d4 a3a2 d4c5 a2a3 c5d6 a3a2 d6
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a7 a3a2 a7b6 a2a3 b6c5 a3a2 c5d4 a2a3 d4c3 f7f6 c3d4 a3a2 d4c5 a2a3 c5d6 a3a2 d6
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8a7 a3a2 a7b6 a2a3 b6c5 a3a2 c5d4 a2a3 d4c3 f7f6 c3d4 a3a2 d4c5 a2a3 c5d6 a3a2 d
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1934 time 23531 pv c3b4 a3a2 b4a5 a2a3 a5b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a2a3 b
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8a7 a3a2 a7b6 a2a3 b6c5 a3a2 c5d4 a2a3 d4c3 f7f6 c3d4 a3a2 d4c5 a2a3 c5d6 a3a2 d
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info currmove c3b4 currmovenumber 1
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0610 time 23578 pv c3b4 a3a2 b4a5 a2a3 a5b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a2a3 b
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d6c7 a2a3 c7b6 a3a2 b6a7 a2a3 a7a8 a3a2 a8b8 a4a3 b8c7
info currmove c3b4 currmovenumber 1
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