Below is a list of positions that are losing for the side to move (side to move is mated in 1), but zurichess' statitic evaluation returns +500 cp for the side to move.
How does your engine king safety fares here? Is there a particular evaluation that detects these ones?
2b2q1k/5P1p/p7/1p1pB3/3P4/1P6/5PP1/6K1 b - -
1q5r/pp3N2/n3rp1k/2P4p/3PP3/PP6/1K5R/6R1 b - -
1r6/5Q2/4p2k/1n1pP1P1/2bP2P1/6K1/q4P2/4N3 b - -
r1b5/1p1n4/p3q1r1/4p3/7Q/5P2/P2Bp1kR/K7 b - -
5r1r/1bqnQp2/1pp1n3/p6p/P1PpPk1N/3P3P/P5P1/1RB3K1 b - -
1k3N2/1p4Q1/p4N2/1b6/1q6/3r3P/3p2P1/1K1R3R w - -
r1b5/1p3p2/p3p1pp/6P1/7k/1P4QP/P4P2/2q2BK1 b - -
3rb2r/NRk5/4p1p1/p4pq1/2PP4/P7/P4PB1/4R1K1 b - -
1r1kbb2/1n4R1/p3N3/1p5r/7p/2B4P/1P3PP1/6K1 b - -
rr3k2/qb2b1pB/2p1Nnp1/3pN3/3P1P2/4P2P/P5P1/1R3RK1 b - -
r1b5/pp3p2/n3Bq1b/1Np5/2Pp1kR1/3P4/PP2PP2/R3K3 b Q -
2r1r2k/2qN1B2/p1b1pBPb/PpPp4/1P3P2/3R4/8/6K1 b - -
2r3k1/3n2p1/2pbNn1p/3pNp1P/3P4/1pQPP3/qP1B1PP1/1K1R3R w - -
q3brk1/2n2p2/rp2pB2/2b5/P1P1p3/4PB2/3N1P2/R3K2R b KQ -
1kN2b1r/Qprbqp2/p4npp/4p3/P3P3/3P3P/1PP3P1/R4RK1 b - -
3r4/4qp1Q/r3p3/3pP1k1/PpPR3p/1P3PpP/8/6K1 b - -
q3r3/1b5N/1p3Q2/3p4/PPp4k/3n4/3P1PP1/3K4 b - -
2r3k1/7R/5BK1/6p1/8/p5rp/8/8 b - -
3R2k1/prp2r1p/4N1p1/4qp2/4p3/1P2P3/P1R2PPP/6K1 b - -
7r/6R1/4pP1k/1p2nN1p/1P5N/8/3q2P1/6K1 b - -
8/2Q3pk/1N5p/4P3/8/5qr1/7R/2R3K1 w - -
rn3Q2/1qp3p1/pp3k1p/2r1b3/5P1N/P5P1/1P5P/3R2K1 b - -
3Q4/5Rpk/4p2p/p1p1P3/P4B2/2r5/2q5/1K1R4 w - -
r1q2r1k/1b2np2/p2p1P1Q/1p2p3/4P3/P7/1PP1BP2/1K1R4 b - -
8/7k/5NR1/p3pP2/P3P3/6K1/4r3/1q6 b - -
1r1b2kR/3q4/1p6/p1r1pP2/P1P1N1P1/3P2K1/8/7R b - -
r3r1k1/1pq1bp1p/p2p1B2/2p5/P3P3/1P4Q1/2PP3P/2K5 b - -
2k3rr/2P5/8/5p2/pP2pb2/P2P3Q/1R3P1K/N2R4 w - -
6k1/4r3/n1pb1n2/p2p4/1P1P1p2/1PB1pPrK/N1P1B3/R2QR3 w - -
8/1pp1kp2/8/2r3r1/4B2K/Q3P2R/PP3q2/R1B5 w - -
2b1k2r/1p1pq2p/p3pK2/2b2pp1/P1P5/1Q2P1B1/5PPP/R4BNR w k -
6k1/1p2ppb1/1Q1N1n1p/5b1P/2r3p1/2B2P2/1Kq1P1P1/3R1BNR w - -
7k/6pp/8/8/NQR4P/P5R1/5r1K/5q2 w - -
1rb5/7B/2p4Q/4q3/2PP2Pk/7P/r4P2/6K1 b - -
n1k4r/3Qnpp1/4p2p/2N1P2P/8/8/Pq3PP1/6K1 b - -
7k/PR1Q2p1/2R2p2/8/3P1PPp/n6P/8/3qr1K1 w - -
rB5k/p4Qp1/4p2p/1K6/1qPNb3/3n3P/5PP1/R4B1R w - -
6k1/QR3p2/6pp/8/1BR1P1P1/5q1P/6K1/5r2 w - -
brtzsnr wrote:If the position comes up in the middle of the search tree, yes, but at leafs, it's not. For example this one prompted me to find more of bad examples.
r7/1b3pkp/np4p1/p1ppR1Q1/2P3N1/Pq4P1/4BP1P/6K1 w - - 0 28
The position above caused a blunder on FICS. Higher depths mitigate some of the king-safety issues, but they are harder to reach.
I'm with Stan that mostly is unnecessary to evaluate when in check.
This position you show should be also resolved by search. What was the blunder?
brtzsnr wrote:
The moves g8g7 and b7c6 are equally bad, lichess says so.
One think I needed relative long time to understand was how was possible that the strongest engines find easy long (or short) tactical lines. Is because as you improve it, this capability emerges from the aggregate of knowledge features in eval function, better search, correct quiescence...
Positions that are in check are not interesting or useful to evaluate. The engine should evade the check and then evaluate. Here is a more interesting position from a recent game that Spartacus won:
[d]3r4/1p1rB1k1/p1p1p1p1/P3P1Pq/1P1R1Q1p/5P1P/6K1/8 b - -
Many engines will assess the position as better for black because of the advantage of material and the weakness of the white king. However, Stockfish correctly evaluates this as a win for white, mainly because of extra code that evaluates the danger of Queen contact.
D Sceviour wrote:Positions that are in check are not interesting or useful to evaluate. The engine should evade the check and then evaluate. Here is a more interesting position from a recent game that Spartacus won:
[d]3r4/1p1rB1k1/p1p1p1p1/P3P1Pq/1P1R1Q1p/5P1P/6K1/8 b - -
Many engines will assess the position as better for black because of the advantage of material and the weakness of the white king. However, Stockfish correctly evaluates this as a win for white, mainly because of extra code that evaluates the danger of Queen contact.
This is dangerous however. Larry K posted a position last week where the same thing happened but was dead wrong, as the queen contact checks were completely meaningless. Queen contact checks in return for giving up an exchange is risky..
bob wrote: Queen contact checks in return for giving up an exchange is risky..
I recently added a Queen contact evaluation to one of two otherwise identical programs. A 300 game match showed a significant increase in elo, so the risk is worth it. King safety is very important as variations in evaluations are larger than any other evaluation - even material.
