Home * Engine Testing * Test-Positions * Silent but deadly

Silent but deadly (sbd),
an EPD test by Dann Corbit that is designed to help tune chess engines. First published in CCC. In August 2008, Dann found a novelty in one of the positions [1].
Vincent van Gogh [2],
Skull of a Skeleton with Burning Cigarette (1886)


This is an EPD test that is designed to help tune chess engines. All of the positions are fairly quiet, and the best move is not a capture. The evaluation for the position is intended to be below one pawn for a one minute search. There are a few positions that have a score a bit larger than one pawn (marked polar) and there are a few positions that have more than one solution (marked Multiple solutions). I would like to see suggestions for replacements for the positions with comments attached. For each of these positions, ultra strong chess players chose the marked best move, as well as many strong chess engines (including Rybka and Naum at 150 seconds). So the test suite should be fairly well debugged. However, I will be very interested in any defects that can be discovered. The main intention is that you can use it to tune your chess engines at shallow depths for positional or otherwise quiet moves.


1qr3k1/p2nbppp/bp2p3/3p4/3P4/1P2PNP1/P2Q1PBP/1N2R1K1 b - - bm Qc7; id "sbd.001";
1r2r1k1/3bnppp/p2q4/2RPp3/4P3/6P1/2Q1NPBP/2R3K1 w - - bm Rc7; id "sbd.002";
2b1k2r/2p2ppp/1qp4n/7B/1p2P3/5Q2/PPPr2PP/R2N1R1K b k - bm O-O; id "sbd.003";
2b5/1p4k1/p2R2P1/4Np2/1P3Pp1/1r6/5K2/8 w - - bm Rd8; id "sbd.004";
2brr1k1/ppq2ppp/2pb1n2/8/3NP3/2P2P2/P1Q2BPP/1R1R1BK1 w - - bm g3; id "sbd.005";
2kr2nr/1pp3pp/p1pb4/4p2b/4P1P1/5N1P/PPPN1P2/R1B1R1K1 b - - bm Bf7; id "sbd.006";
2r1k2r/1p1qbppp/p3pn2/3pBb2/3P4/1QN1P3/PP2BPPP/2R2RK1 b k - bm O-O; id "sbd.007";
2r1r1k1/pbpp1npp/1p1b3q/3P4/4RN1P/1P4P1/PB1Q1PB1/2R3K1 w - - bm Rce1; id "sbd.008";
2r2k2/r4p2/2b1p1p1/1p1p2Pp/3R1P1P/P1P5/1PB5/2K1R3 w - - bm Kd2; id "sbd.009";
2r3k1/5pp1/1p2p1np/p1q5/P1P4P/1P1Q1NP1/5PK1/R7 w - - bm Rd1; id "sbd.010";
2r3qk/p5p1/1n3p1p/4PQ2/8/3B4/5P1P/3R2K1 w - - bm e6; id "sbd.011";
3b4/3k1pp1/p1pP2q1/1p2B2p/1P2P1P1/P2Q3P/4K3/8 w - - bm Qf3; id "sbd.012";
3n1r1k/2p1p1bp/Rn4p1/6N1/3P3P/2N1B3/2r2PP1/5RK1 w - - bm Na4 Nce4; id "sbd.013";
3q1rk1/3rbppp/ppbppn2/1N6/2P1P3/BP6/P1B1QPPP/R3R1K1 w - - bm Nd4; id "sbd.014";
3r1rk1/p1q4p/1pP1ppp1/2n1b1B1/2P5/6P1/P1Q2PBP/1R3RK1 w - - bm Bh6; id "sbd.015";
3r2k1/2q2p1p/5bp1/p1pP4/PpQ5/1P3NP1/5PKP/3R4 b - - bm Qd6; id "sbd.016";
3r2k1/p1q1npp1/3r1n1p/2p1p3/4P2B/P1P2Q1P/B4PP1/1R2R1K1 w - - bm Bc4; id "sbd.017";
3r4/2k5/p3N3/4p3/1p1p4/4r3/PPP3P1/1K1R4 b - - bm Kd7; id "sbd.018";
3r4/2R1np1p/1p1rpk2/p2b1p2/8/PP2P3/4BPPP/2R1NK2 w - - bm b4; id "sbd.019";
3rk2r/1b2bppp/p1qppn2/1p6/4P3/PBN2PQ1/1PP3PP/R1B1R1K1 b k - bm O-O; id "sbd.020";
3rk2r/1bq2pp1/2pb1n1p/p3pP2/P1B1P3/8/1P2QBPP/2RN1R1K b k - bm Be7 O-O; id "sbd.021";
3rkb1r/pppb1pp1/4n2p/2p5/3NN3/1P5P/PBP2PP1/3RR1K1 w - - bm Nf5; id "sbd.022";
3rr1k1/1pq2ppp/p1n5/3p4/6b1/2P2N2/PP1QBPPP/3R1RK1 w - - bm Rfe1; id "sbd.023";
4r1k1/1q1n1ppp/3pp3/rp6/p2PP3/N5P1/PPQ2P1P/3RR1K1 w - - bm Rc1; id "sbd.024";
4rb1k/1bqn1pp1/p3rn1p/1p2pN2/1PP1p1N1/P1P2Q1P/1BB2PP1/3RR1K1 w - - bm Qe2; id "sbd.025";
4rr2/2p5/1p1p1kp1/p6p/P1P4P/6P1/1P3PK1/3R1R2 w - - bm Rfe1; id "sbd.026";
5r2/pp1b1kpp/8/2pPp3/2P1p2P/4P1r1/PPRKB1P1/6R1 b - - bm Ke7; id "sbd.027";
6k1/1R5p/r2p2p1/2pN2B1/2bb4/P7/1P1K2PP/8 w - - bm Nf6+; id "sbd.028";
6k1/pp1q1pp1/2nBp1bp/P2pP3/3P4/8/1P2BPPP/2Q3K1 w - - bm Qc5; id "sbd.029";
6k1/pp2rp1p/2p2bp1/1n1n4/1PN3P1/P2rP2P/R3NPK1/2B2R2 w - - bm Rd2; id "sbd.030";
8/2p2kpp/p6r/4Pp2/1P2pPb1/2P3P1/P2B1K1P/4R3 w - - bm h4; id "sbd.031";
Q5k1/5pp1/5n1p/2b2P2/8/5N1P/5PP1/2q1B1K1 b - - bm Kh7; id "sbd.032";
r1b1k1nr/1p3ppp/p1np4/4p1q1/2P1P3/N1NB4/PP3PPP/2RQK2R w Kkq - bm O-O; id "sbd.033";
r1b1k2r/p1pp1ppp/1np1q3/4P3/1bP5/1P6/PB1NQPPP/R3KB1R b KQkq - bm O-O; id "sbd.034";
r1b1k2r/ppppqppp/8/2bP4/3p4/6P1/PPQPPPBP/R1B2RK1 b kq - bm O-O; id "sbd.035";
r1b1k2r/ppq1bppp/2n5/2N1p3/8/2P1B1P1/P3PPBP/R2Q1RK1 b kq - bm O-O; id "sbd.036";
r1b1kb1r/pp2qppp/2pp4/8/4nP2/2N2N2/PPPP2PP/R1BQK2R w KQkq - bm O-O; id "sbd.037";
r1b1qrk1/pp4b1/2pRn1pp/5p2/2n2B2/2N2NPP/PPQ1PPB1/5RK1 w - - bm Rd3; id "sbd.038";
r1b2rk1/1pqn1pp1/p2bpn1p/8/3P4/2NB1N2/PPQB1PPP/3R1RK1 w - - bm Rc1; id "sbd.039";
r1b2rk1/2qnbp1p/p1npp1p1/1p4PQ/4PP2/1NNBB3/PPP4P/R4RK1 w - - bm Qh6; id "sbd.040";
r1b2rk1/pp2ppbp/2n2np1/2q5/5B2/1BN1PN2/PP3PPP/2RQK2R w K - bm O-O; id "sbd.041";
r1b2rk1/pp4pp/1q1Nppn1/2n4B/1P3P2/2B2RP1/P6P/R2Q3K b - - bm Na6; id "sbd.042";
r1b2rk1/ppp1qppp/1b1n4/8/B2n4/3NN3/PPPP1PPP/R1BQK2R w KQ - bm O-O; id "sbd.043";
r1b2rk1/ppq1bppp/2p1pn2/8/2NP4/2N1P3/PP2BPPP/2RQK2R w K - bm O-O; id "sbd.044";
r1bq1rk1/1p1n1pp1/p4n1p/2bp4/8/2NBPN2/PPQB1PPP/R3K2R w KQ - bm O-O; id "sbd.045";
r1bq1rk1/1p2ppbp/p2p1np1/6B1/2P1P3/2N5/PP1QBPPP/R3K2R w KQ - bm O-O; id "sbd.046";
r1bq1rk1/1p3ppp/p1np4/3Np1b1/2B1P3/P7/1PP2PPP/RN1QK2R w KQ - bm O-O; id "sbd.047";
r1bq1rk1/4bppp/ppnppn2/8/2P1P3/2N5/PPN1BPPP/R1BQK2R w KQ - bm O-O; id "sbd.048";
r1bq1rk1/pp1n1pbp/2n1p1p1/2ppP3/8/2PP1NP1/PP1N1PBP/R1BQ1RK1 w - - bm d4; id "sbd.049";
r1bq1rk1/pp1pppbp/2n2np1/8/4P3/1NN5/PPP1BPPP/R1BQK2R w KQ - bm O-O; id "sbd.050";
r1bq1rk1/pp2ppbp/2n2np1/2p3B1/4P3/2P2N2/PP1NBPPP/R2QK2R w KQ - bm O-O; id "sbd.051";
r1bq1rk1/pp2ppbp/2n3p1/2p5/2BPP3/2P1B3/P3NPPP/R2QK2R w KQ - bm O-O; id "sbd.052";
r1bq1rk1/pp3ppp/2n1pn2/2p5/1bBP4/2N1PN2/PP3PPP/R1BQ1RK1 w - - bm a3; id "sbd.053";
r1bq1rk1/pp3ppp/2n2n2/3p4/8/P1NB4/1PP2PPP/R1BQK2R w KQ - bm O-O; id "sbd.054";
r1bq1rk1/ppp1npb1/3p2pp/3Pp2n/1PP1P3/2N5/P2NBPPP/R1BQR1K1 b - - bm Nf4; id "sbd.055";
r1bq1rk1/ppp2ppp/2n1pn2/3p4/1bPP4/2NBPN2/PP3PPP/R1BQK2R w KQ - bm O-O; id "sbd.056";
r1bq1rk1/pppp1pbp/2n2np1/4p3/2P5/P1N2NP1/1P1PPPBP/R1BQK2R w KQ - bm O-O; id "sbd.057";
r1bqk2r/2ppbppp/p1n2n2/1p2p3/4P3/1B3N2/PPPPQPPP/RNB2RK1 b kq - bm O-O; id "sbd.058";
r1bqk2r/5ppp/p1np4/1p1Np1b1/4P3/2P5/PPN2PPP/R2QKB1R b KQkq - bm O-O; id "sbd.059";
r1bqk2r/bp3ppp/p1n1pn2/3p4/1PP5/P1N1PN2/1B3PPP/R2QKB1R b KQkq - bm O-O; id "sbd.060";
r1bqk2r/p2pppbp/2p3pn/2p5/4P3/2P2N2/PP1P1PPP/RNBQR1K1 b kq - bm O-O; id "sbd.061";
r1bqk2r/pp2bppp/2n1p3/1B1n4/3P4/2N2N2/PP3PPP/R1BQ1RK1 b kq - bm O-O; id "sbd.062";
r1bqk2r/pp2bppp/2n1p3/3n4/3P4/2NB1N2/PP3PPP/R1BQ1RK1 b kq - bm O-O; id "sbd.063";
r1bqk2r/pp2ppbp/2np1np1/2p5/4P3/1B1P1N1P/PPP2PP1/RNBQK2R w KQkq - bm O-O; id "sbd.064";
r1bqk2r/ppn1bppp/2n5/2p1p3/8/2NP1NP1/PP1BPPBP/R2Q1RK1 b kq - bm O-O; id "sbd.065";
r1bqk2r/ppp1bppp/2n5/3p4/3P4/2PB1N2/P1P2PPP/R1BQ1RK1 b kq - bm O-O; id "sbd.066";
r1bqk2r/ppp2ppp/2nb4/3np3/8/PP2P3/1BQP1PPP/RN2KBNR b KQkq - bm O-O; id "sbd.067";
r1bqk2r/ppp2ppp/3b4/4p3/8/1PPP1N2/2PB1PPP/R2Q1RK1 b kq - bm O-O; id "sbd.068";
r1bqk2r/pppp1ppp/5n2/4p3/Bb2P3/5Q2/PPPPNPPP/R1B1K2R b KQkq - bm O-O; id "sbd.069";
r1bqkb1r/pp3ppp/2n5/2pp4/3Pn3/2N2N2/PPP1BPPP/R1BQK2R w KQkq - bm O-O; id "sbd.070";
r1bqkb1r/pp3ppp/2npp3/3nP3/2BP4/5N2/PP3PPP/RNBQK2R w KQkq - bm O-O; id "sbd.071";
r1bqkbnr/3p1ppp/p1p1p3/8/4P3/3B4/PPP2PPP/RNBQK2R w KQkq - bm O-O; id "sbd.072";
r1bqkbnr/ppp2ppp/2n5/8/2BpP3/5N2/PP3PPP/RNBQK2R w KQkq - bm O-O; id "sbd.073";
r1bqrbk1/1pp3pp/2n2p2/p2np3/8/PP1PPN2/1BQNBPPP/R3K2R w KQ - bm O-O; id "sbd.074";
r1br2k1/1p2qppp/pN2pn2/P7/2pn4/4N1P1/1P2PPBP/R3QRK1 b - - bm Rb8; id "sbd.075";
r1q1k2r/1b1nbppp/pp1ppn2/8/2PQP3/1PN2NP1/PB3PBP/R2R2K1 b kq - bm O-O; id "sbd.076";
r1q1k2r/pb1nbppp/1p2pn2/8/P1PNP3/2B3P1/2QN1PBP/R4RK1 b kq - bm O-O; id "sbd.077";
r1r3k1/1bq2pbp/pp1pp1p1/2n5/P3PP2/R2B4/1PPBQ1PP/3N1R1K w - - bm Bc3; id "sbd.078";
r1rn2k1/pp1qppbp/6p1/3pP3/3P4/1P3N1P/PB1Q1PP1/R3R1K1 w - - bm Rac1; id "sbd.079";
r2q1rk1/1b1nbpp1/pp2pn1p/8/2BN3B/2N1P3/PP2QPPP/2R2RK1 w - - bm Rfd1; id "sbd.080";
r2q1rk1/1b3ppp/4pn2/1pP5/1b6/2NBPN2/1PQ2PPP/R3K2R w KQ - bm O-O; id "sbd.081";
r2q1rk1/pb1nppbp/6p1/1p6/3PP3/3QBN1P/P3BPP1/R3K2R w KQ - bm O-O; id "sbd.082";
r2q1rk1/pb2bppp/npp1pn2/3pN3/2PP4/1PB3P1/P2NPPBP/R2Q1RK1 w - - bm e4; id "sbd.083";
r2q1rk1/pppb1pbp/2np1np1/4p3/2P5/P1NPPNP1/1P3PBP/R1BQK2R w KQ - bm O-O; id "sbd.084";
r2qk2r/1b1n1ppp/4pn2/p7/1pPP4/3BPN2/1B3PPP/R2QK2R w KQkq - bm O-O; id "sbd.085";
r2qk2r/1b2bppp/p1n1pn2/1p6/1P6/P2BPN2/1B2QPPP/RN3RK1 b kq - bm O-O; id "sbd.086";
r2qk2r/2p2ppp/p1n1b3/1pbpP3/4n3/1BP2N2/PP1N1PPP/R1BQ1RK1 b kq - bm O-O; id "sbd.087";
r2qk2r/3n1ppp/p3p3/3nP3/3R4/5N2/1P1N1PPP/3QR1K1 b kq - bm O-O; id "sbd.088";
r2qk2r/p1pn1ppp/b3pn2/3p4/Nb1P4/1P3NP1/P3PPBP/1RBQ1RK1 b kq - bm O-O Qe7; id "sbd.089";
r2qk2r/ppp1bppp/2n2n2/8/2BP2b1/2N2N2/PP3PPP/R1BQR1K1 b kq - bm O-O; id "sbd.090";
r2qkb1r/pb1n1p2/2p1p2p/4P1pn/PppP4/2N2NB1/1P2BPPP/R2Q1RK1 w kq - bm Ne4; id "sbd.091";
r2qkb1r/pp2nppp/1np1p3/4Pb2/3P4/PB3N2/1P3PPP/RNBQ1RK1 b kq - bm Ned5; id "sbd.092";
r2qkb1r/pp3ppp/2bppn2/8/2PQP3/2N2N2/PP3PPP/R1B1K2R w KQkq - bm O-O; id "sbd.093";
r2qr1k1/p3bppp/1p2n3/3Q1N2/5P2/4B1P1/PP3R1P/R5K1 w - - bm Rd1; id "sbd.094";
r2r2k1/p1pnqpp1/1p2p2p/3b4/3P4/3BPN2/PP3PPP/2RQR1K1 b - - bm c5; id "sbd.095";
r2r2k1/pp1b1ppp/8/3p2P1/3N4/P3P3/1P3P1P/3RK2R b K - bm Rac8; id "sbd.096";
r3k2r/1b1nb1p1/p1q1pn1p/1pp3N1/4PP2/2N5/PPB3PP/R1BQ1RK1 w kq - bm Nf3; id "sbd.097";
r3k2r/1pqnnppp/p5b1/1PPp1p2/3P4/2N5/P2NB1PP/2RQ1RK1 b kq - bm O-O; id "sbd.098";
r3k2r/p1q1nppp/1pn5/2P1p3/4P1Q1/P1P2P2/4N1PP/R1B2K1R b kq - bm O-O; id "sbd.099";
r3k2r/pp2pp1p/6p1/2nP4/1R2PB2/4PK2/P5PP/5bNR w kq - bm Ne2; id "sbd.100";
r3k2r/ppp1bppp/2n5/3n4/3PB3/8/PP3PPP/RNB1R1K1 b kq - bm O-O-O; id "sbd.101";
r3kb1r/pp3ppp/4bn2/3p4/P7/4N1P1/1P2PPBP/R1B1K2R w KQkq - bm O-O; id "sbd.102";
r3kbnr/1pp3pp/p1p2p2/8/3qP3/5Q1P/PP3PP1/RNB2RK1 w kq - bm Rd1; id "sbd.103";
r3kr2/pppb1p2/2n3p1/3Bp2p/4P2N/2P5/PP3PPP/2KR3R b q - bm O-O-O; id "sbd.104";
r3nrk1/pp2qpb1/3p1npp/2pPp3/2P1P2N/2N3Pb/PP1BBP1P/R2Q1RK1 w - - bm Re1; id "sbd.105";
r3r1k1/1pqn1pbp/p2p2p1/2nP2B1/P1P1P3/2NB3P/5PP1/R2QR1K1 w - - bm Rc1; id "sbd.106";
r3r1k1/pp1q1ppp/2p5/P2n1p2/1b1P4/1B2PP2/1PQ3PP/R1B2RK1 w - - bm e4; id "sbd.107";
r3r1k1/pp3ppp/2ppqn2/5R2/2P5/2PQP1P1/P2P2BP/5RK1 w - - bm Qd4; id "sbd.108";
r3rbk1/p2b1p2/5p1p/1q1p4/N7/6P1/PP1BPPBP/3Q1RK1 w - - bm Nc3; id "sbd.109";
r4r1k/pp1bq1b1/n2p2p1/2pPp1Np/2P4P/P1N1BP2/1P1Q2P1/2KR3R w - - bm Ne6; id "sbd.110";
r4rk1/1bqp1ppp/pp2pn2/4b3/P1P1P3/2N2BP1/1PQB1P1P/2R2RK1 w - - bm b3; id "sbd.111";
r4rk1/1q2bppp/p1bppn2/8/3BPP2/3B2Q1/1PP1N1PP/4RR1K w - - bm e5; id "sbd.112";
r4rk1/pp2qpp1/2pRb2p/4P3/2p5/2Q1PN2/PP3PPP/4K2R w K - bm O-O; id "sbd.113";
r7/3rq1kp/2p1bpp1/p1Pnp3/2B4P/PP4P1/1B1RQP2/2R3K1 b - - bm Rad8; id "sbd.114";
r7/pp1bpp2/1n1p2pk/1B3P2/4P1P1/2N5/PPP5/1K5R b - - bm Kg5; id "sbd.115";
rn1q1rk1/p4pbp/bp1p1np1/2pP4/8/P1N2NP1/1PQ1PPBP/R1B1K2R w KQ - bm O-O; id "sbd.116";
rn1q1rk1/pb3p2/1p5p/3n2P1/3p4/P4P2/1P1Q1BP1/R3KBNR b KQ - bm Re8+; id "sbd.117";
rn1q1rk1/pp2bppp/1n2p1b1/8/2pPP3/1BN1BP2/PP2N1PP/R2Q1RK1 w - - bm Bc2; id "sbd.118";
rn1q1rk1/pp3ppp/4bn2/2bp4/5B2/2NBP1N1/PP3PPP/R2QK2R w KQ - bm O-O; id "sbd.119";
rn1qkbnr/pp1b1ppp/8/1Bpp4/3P4/8/PPPNQPPP/R1B1K1NR b KQkq - bm Qe7; id "sbd.120";
rn1qr1k1/pb3p2/1p5p/3n2P1/3p4/P4P2/1P1QNBP1/R3KB1R b KQ - bm d3; id "sbd.121";
rn2kb1r/pp2nppp/1q2p3/3pP3/3P4/5N2/PP2NPPP/R1BQK2R w KQkq - bm O-O; id "sbd.122";
rn3rk1/1bqp1ppp/p3pn2/8/Nb1NP3/4B3/PP2BPPP/R2Q1RK1 w - - bm Rc1; id "sbd.123";
rn3rk1/pbp1qppp/1p1ppn2/8/2PP4/P1Q2NP1/1P2PPBP/R1B1K2R w KQ - bm O-O; id "sbd.124";
rnb1k2r/1pq2ppp/p2ppn2/2b5/3NPP2/2P2B2/PP4PP/RNBQ1R1K b kq - bm O-O; id "sbd.125";
rnb2rk1/ppq1ppbp/6p1/2p5/3PP3/2P2N2/P3BPPP/1RBQK2R w K - bm O-O; id "sbd.126";
rnbq1rk1/5ppp/p3pn2/1p6/2BP4/P1P2N2/5PPP/R1BQ1RK1 w - - bm Bd3; id "sbd.127";
rnbq1rk1/pp2ppbp/2pp1np1/8/P2PP3/2N2N2/1PP1BPPP/R1BQK2R w KQ - bm O-O; id "sbd.128";
rnbq1rk1/ppp1ppbp/6p1/8/8/2P2NP1/P2PPPBP/R1BQK2R w KQ - bm O-O; id "sbd.129";
rnbqk1nr/pp3pbp/2ppp1p1/8/2BPP3/2N2Q2/PPP2PPP/R1B1K1NR w KQkq - bm Nge2; id "sbd.130";
rnbqk2r/ppp2ppp/1b1p1n2/4p3/2B1P3/2PP1N2/PP1N1PPP/R1BQK2R b KQkq - bm O-O; id "sbd.131";
rnbqk2r/pppp2pp/4pn2/5p2/1b1P4/2P2NP1/PP2PPBP/RNBQK2R b KQkq - bm Be7; id "sbd.132";
rnbqr1k1/pp1p1ppp/5n2/3Pb3/1P6/P1N3P1/4NPBP/R1BQK2R w KQ - bm O-O; id "sbd.133";
rnq1nrk1/pp3pbp/6p1/3p4/3P4/5N2/PP2BPPP/R1BQK2R w KQ - bm O-O; id "sbd.134";


  1. ^ From the silent but deadly set, a novelty by Dann Corbit, CCC, August 12, 2008
  2. ^ Skull of a Skeleton with Burning Cigarette (1886), oil on canvas, Van Gogh Museum, Amsterdam, Vincent van Gogh from Wikipedia, Wikimedia Commons
  3. ^ Silent but deadly by Dann Corbit, CCC, May 7, 2008

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