Author: Colin Frayn
Date: 02:18:51 04/29/00
Go up one level in this thread
On April 28, 2000 at 12:36:55, Dann Corbit wrote:
>I was watching some chess engines play last night, and this position came up:
>8/4kp1p/4p3/1b1pP1P1/prpP1P2/5K2/1P1R4/3B4 b - -
>
>To my abject horror, the side to move did not play c3
>
>My question is, did black throw away a win, or are my instincts just wrong
>again?
ColChess thinks the following; (all scores given are, as usual, improvements
from the current position, not absolute scores)
Current Position
----------------
. . . . . . . .
. . . . k p . p pP=Pawn
. . . . p . . . rR=Rook
. b . p P . P . nN=Knight lower=Black
p r p P . P . . bB=Bishop CAPS=White
. . . . . K . . qQ=Queen
. P . R . . . . kK=King
. . . B . . . .
Thinking [16 Moves]
Current Position=1.97
{L2} :::::::: B5 - C6 (-0.02) Nodes=565 Eval=278 [0.02s]
{L3} :::::::: B5 - C6 (0.10) Nodes=1426 Eval=606 [0.05s]
{L4} :::::::: B5 - C6 (0.08) Nodes=6730 Eval=1778 [0.11s]
{L5} :::::::: B5 - C6 (0.08) Nodes=21870 Eval=7224 [0.43s]
{L6} :::::::: B5 - D7 (0.02) Nodes=113412 Eval=31059 [1.77s]
{L7} :::::::: B5 - D7 (0.02) Nodes=244807 Eval=72187 [4.84s]
{L8} :::::::: B5 - D7 (0.01) Nodes=695410 Eval=173544 [12.05s]
{L9} :::::::: B5 - C6 (-0.03) Nodes=4882047 Eval=1245494 [64.38s]
{L10} :::::::: E7 - F8 (-0.03) Nodes=63618867 Eval=19726029 [903.3s]
15 Minutes, 3 Seconds
Nodes=69585134 Eval=21258199
Table Hits=1296864 [310689 Entries]
PV : e7f8 d2h2 b5c6 f3g4 c6d7 g4f3 d7c6 f3e3 f8g8 h2e2
...though it didn't search deep enough to pick up a3 if that is indeed the best
move. However, it never did choose c3. :)
After black plays c3, it thinks....
Current Position
----------------
. . . . . . . .
. . . . k p . p pP=Pawn
. . . . p . . . rR=Rook
. b . p P . P . nN=Knight lower=Black
p r . P . P . . bB=Bishop CAPS=White
. . p . . K . . qQ=Queen
. P . R . . . . kK=King
. . . B . . . .
Thinking [19 Moves]
Current Position=-2.61
{L2} :::::::::. B2 x C3 (5.40) Nodes=557 Eval=132 [0.01s]
{L3} :::::::::. B2 x C3 (2.35) Nodes=1389 Eval=527 [0.04s]
{L4} :::::::::. B2 x C3 (2.21) Nodes=6896 Eval=1557 [0.13s]
{L5} :::::::::. B2 x C3 (2.41) Nodes=14407 Eval=4526 [0.40s]
{L6} :::::::::. B2 x C3 (2.34) Nodes=69381 Eval=15116 [1.18s]
{L7} :::::::::. B2 x C3 (2.33) Nodes=139592 Eval=38498 [3.33s]
{L8} :::::::::. B2 x C3 (2.40) Nodes=619812 Eval=129157 [10.08s]
{L9} :::::::::. B2 x C3 (1.98) Nodes=1037974 Eval=277698 [25.25s]
25.2 Seconds - D'oh
Nodes=1890008 Eval=467211
Table Hits=66943 [52964 Entries]
PV : b2c3 b4b1 d1c2 b1b2 f3e3 a4a3 f4f5 e6f5 c2f5
...so it looks like c3 loses 2 pawns worth whereas the other moves chosen (to
the depth searched) lose virtually nothing.
Cheers,
Colin
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