Rabid Queen only

Henk · Post by **Henk** » Sat Jan 28, 2017 9:32 pm

See end of game

[pgn]
[Event "Computer Chess Game"]
[Site "HP"]
[Date "2017.01.28"]
[Round "-"]
[White "Fairy-Max 4.8S"]
[Black "SkipperWinb"]
[Result "1/2-1/2"]
[TimeControl "120"]
[Annotator "1. +0.10 1... +0.03"]

1. d3 {+0.10/8} g6 {+0.03/121 2.0} 2. Bg5 {+0.09/8 5} c6 {+0.21/101 2.0} 3.
c4 {+0.12/7 1.5} Bg7 {+1.04/121 2.0} 4. Nc3 {-0.12/8 2.0} Qc7
{+0.44/101 1.9} 5. Nf3 {-0.08/7 1.4} d6 {+0.94/101 1.9} 6. Qa4 {-0.18/8 4}
h6 {+0.81/101 1.9} 7. Be3 {-0.05/8 1.5} h5 {+0.73/81 1.9} 8. Nd5
{+0.71/7 2.4} Qd7 {+0.51/101 1.8} 9. Nb6 {+1.46/11 2.4} axb6
{+0.76/121 1.8} 10. Qxa8 {+1.59/11 1.7} Bxb2 {+0.45/121 1.8} 11. Rb1
{+1.48/11 2.3} Bc3+ {-0.43/141 1.7} 12. Nd2 {+1.56/11 5} Na6
{-0.31/121 1.7} 13. Rxb6 {+1.58/11 11} Qc7 {-0.12/101 1.7} 14. Rb3
{+1.77/8 1.0} Ba5 {-0.29/101 1.7} 15. Ra3 {+1.66/9 1.4} Bb4 {-0.39/121 1.6}
16. Bb6 {+1.51/10 6} Qd7 {-0.27/121 1.6} 17. Rb3 {+1.57/10 2.1} Bc5
{-0.42/121 1.6} 18. Ne4 {+1.76/8 1.0} Bb4+ {-0.66/121 1.6} 19. Nc3
{+1.58/8 1.2} Bc5 {-0.48/121 1.5} 20. Na4 {+1.86/8 2.1} Bb4+
{-0.50/121 1.5} 21. Kd1 {+2.09/7 0.8} Nf6 {-0.71/101 1.5} 22. a3
{+2.11/8 2.8} Bc5 {-0.75/101 1.5} 23. d4 {+3.32/8 1.2} Ng4 {-2.31/121 1.5}
24. Ke1 {+3.40/9 1.7} Nc7 {-2.66/121 1.4} 25. Bxc7 {+3.68/9 0.9} Bxd4
{-3.08/101 1.4} 26. Bb6 {+3.84/8 1.0} Be5 {-3.19/101 1.4} 27. Ba7
{+4.04/8 1.4} Qf5 {-3.96/81 1.4} 28. f4 {+3.61/8 3} Bxf4 {-3.12/101 1.3}
29. Nb6 {+3.61/8 1.0} O-O {-3.16/121 1.3} 30. e3 {+1.18/7 1.2} Bxe3
{-0.12/101 1.3} 31. Be2 {-1.49/8 0.8} Qf2+ {+0.91/121 1.3} 32. Kd1
{-2.15/9 0.8} Qxg2 {+3.47/121 1.3} 33. Rf1 {-2.16/9 0.6} Bf5
{+3.28/121 1.3} 34. Qxb7 {-1.99/8 0.7} Bc2+ {+3.61/121 1.2} 35. Ke1
{-2.61/7 1.0} Bxb3 {+4.55/101 1.2} 36. Qxe7 {-4.03/7 0.6} Qxh2
{+6.99/101 1.2} 37. Rf3 {-8.40/9 1.0} Qg1+ {+8.18/121 1.2} 38. Bf1
{-10.42/10 1.5} Bxb6 {+8.40/121 1.2} 39. Bxb6 {-5.90/9 1.0} Qxb6
{+9.66/121 1.2} 40. Bd3 {-6.39/8 0.5} Ne5 {+10.44/101 1.1} 41. Rg3
{-6.69/9 0.7} Qa5+ {+10.85/121 1.1} 42. Ke2 {-7.72/8 0.9} Qxa3
{+10.90/101 1.1} 43. Qg5 {-6.74/8 0.7} Qc5 {+11.52/101 1.1} 44. Qf4
{-7.11/8 0.8} Bxc4 {+11.52/101 1.1} 45. Bxc4 {-6.49/9 0.6} Nxc4
{+11.60/101 1.0} 46. Qe4 {-6.64/8 0.6} d5 {+11.98/121 1.0} 47. Rg5
{-7.09/8 0.4} Qd6 {+11.81/101 1.0} 48. Qh4 {-7.28/8 0.5} Kh7
{+12.01/101 1.0} 49. Rg1 {-7.05/8 0.6} Rb8 {+11.83/101 1.0} 50. Kf1
{-7.34/7 0.7} d4 {+12.15/101 1.1} 51. Rg5 {-7.48/7 0.5} Ne3+
{+12.32/101 1.0} 52. Ke1 {-9.11/7 0.7} Rb2 {+2.70/141 1.0} 53. Rxh5+
{-0.05/12 0.5} gxh5 {+0.00/241 1.0} 54. Qxh5+ {-0.03/11 0.4} Qh6
{+0.00/261 1.0} 55. Qxh6+ {-0.01/13 1.4} Kg8 {+0.00/161 0.9} 56. Qg6+
{-0.01/9 0.4} fxg6 {+0.00/321 0.9}
{Xboard adjudication: Stalemate} 1/2-1/2
[/pgn]

Daniel Anulliero · Post by **Daniel Anulliero** » Sat Jan 28, 2017 10:33 pm

after 52.Ke1 :
[d]1r6/5p1k/2pq2p1/6Rp/3p3Q/4n3/8/4K3 w - - 0 1
Isa play 53 .... Qb4!+ , force 53 Kf2
then It play 54 .... Ng4+ and white lose his Queen or is checkmate

What is a "rabid queen"?

So I think Skipper's move 52 ... Rb2 was a bug

Tony P. · Post by **Tony P.** » Sat Jan 28, 2017 10:48 pm

Daniel Anulliero wrote:What is a "rabid queen"?

A 'rabid' piece is one that checks the opponent's king continuously so that if the king takes it, the owner of the 'rabid' piece will be in stalemate, but if the king doesn't take it, it will be giving perpetual check.

A 'rabid rook' moving along the seventh rank and checking the king that moves along the eighth is a more common tactical theme than what happened in that game.

Technically, it's very seldom possible for a queen to become truly (perpetually) 'rabid' because, once it comes in direct contact with the king, the king most often has to take it, having no escape squares left. So Henk was calling that particular queen 'rabid' only figuratively.

Henk · Post by **Henk** » Sat Jan 28, 2017 10:52 pm

I get this now. Probably was a bug in futility pruning.

[d] 1r6/5p1k/2pq2p1/6Rp/3p3Q/4n3/8/4K3 b - - 0 1

Code: Select all

Depth  Value   Time&#40;seconds&#41;   Nodes
200   12.2020      41.36     5897262   b8b1 e1e2 b1b2 e2f3 c6c5 h4g3 d6f6 f3e4 f6e7 g3e5 
180   12.3180       8.47     1099993   b8b1 e1e2 b1b2 e2f3 f7f5 h4e1 d6d5 f3g3 b2g2 
160   12.3170       4.31      659085   b8b1 e1e2 b1b2 e2d3 b2b3 d3e2 
140   12.3170       2.27      340128   b8b1 e1e2 b1b2 e2d3 b2b3 d3e2 
120   12.1950       1.56      222470   b8b3 h4e4 f7f5 e4e7 
100   12.4200       0.24       34899   b8b1 e1e2 b1b2 e2d3 c6c5 
 80   12.3640       0.14       23576   b8b1 e1e2 b1b2 e2e1 
 60   12.4290       0.02        1881   b8b1 e1d2 f7f5 
 40   12.3440       0.01         606   b8b1 e1d2 
 20   12.5350       0.04         186   d4d3

Tony P. · Post by **Tony P.** » Sat Jan 28, 2017 11:04 pm

Henk wrote:Probably was a bug in futility pruning.

Congrats on fixing it! I find it instructive - engines can make the mistake of underestimating losing captures so much that they fail to see a sacrificial forced draw threatened by the opponent if the node where it happens is pruned or outside the main search tree.

Daniel Anulliero · Post by **Daniel Anulliero** » Sun Jan 29, 2017 10:03 am

Tony P. wrote:
Daniel Anulliero wrote:What is a "rabid queen"?
A 'rabid' piece is one that checks the opponent's king continuously so that if the king takes it, the owner of the 'rabid' piece will be in stalemate, but if the king doesn't take it, it will be giving perpetual check.

A 'rabid rook' moving along the seventh rank and checking the king that moves along the eighth is a more common tactical theme than what happened in that game.

Technically, it's very seldom possible for a queen to become truly (perpetually) 'rabid' because, once it comes in direct contact with the king, the king most often has to take it, having no escape squares left. So Henk was calling that particular queen 'rabid' only figuratively.

Thanks for your answer

Daniel Anulliero · Post by **Daniel Anulliero** » Sun Jan 29, 2017 10:18 am

Tony P. wrote:
Henk wrote:Probably was a bug in futility pruning.
Congrats on fixing it! I find it instructive - engines can make the mistake of underestimating losing captures so much that they fail to see a sacrificial forced draw threatened by the opponent if the node where it happens is pruned or outside the main search tree.

Yes Rb1 is better now but , the bug is not fixed !
Droidfish say the best move is effectively Qb4+ with M9
Isa find the best move but not the mate with 30"

Édit : After 240" it change for Ng2+ , M8

zenpawn · Post by **zenpawn** » Sun Jan 29, 2017 12:12 pm

Henk wrote:I get this now. Probably was a bug in futility pruning.

What did you change to get the new answer?

Henk · Post by **Henk** » Sun Jan 29, 2017 3:32 pm

zenpawn wrote:
Henk wrote:I get this now. Probably was a bug in futility pruning.
What did you change to get the new answer?

I changed something in futility pruning at level 1. But I changed it wrongly. So still not fixed. Maybe too difficult.

Henk · Post by **Henk** » Mon Jan 30, 2017 11:23 am

Henk wrote:
zenpawn wrote:
Henk wrote:I get this now. Probably was a bug in futility pruning.
What did you change to get the new answer?
I changed something in futility pruning at level 1. But I changed it wrongly. So still not fixed. Maybe too difficult.

[d]1r6/5p1k/2pq2p1/6Rp/3p3Q/4n3/8/4K3 w - - 0 1
Added check extension. PV incomplete.

Code: Select all

Depth  Value   Time&#40;seconds&#41;   Nodes
180   16.3840      12.14     1355795   d6b4 
160   16.3840       2.57      302759   d6b4 
140   16.3840       0.56       70942   d6b4 
120   16.3840       0.19       20963   d6b4 
100   12.0910       4.42      555601   e3c2 
 80   14.2680       3.16      395996   b8b1 
 60   12.5590       0.43       62897   b8b1 
 40   12.4140       0.06        7654   b8b1 
 20   12.4910       0.05         645   d4d3

;

Rabid Queen only

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