Stockfish with UCI_LimitStrength can't checkmate RK vs K

[asdfjkl]

Describe the issue

I am developing the chess GUI https://github.com/asdfjkl/jfxchess which allows to play against engines (with UCI_LimitStrength and UCI_Elo). A user reported that Stockfish can't checkmate ( asdfjkl/jfxchess#160 ). At first I thought of a bug in my GUI, but upon further inspection it seems that on various strength levels, Stockfish can't find this simple checkmate - which is quite unexpected behavior for a chess engine that at minimum claims 1300 Elo.

A log is attached. The log was created with stockfish-windows-x86-64-sse41-popcnt.exe, but without further inspection I assume that all versions are affected. Note that distance to mate does not necessarily decrease, as moves with a cp value are selected. A bugfix might either ensure that in case of UCI_LimitStrength and a mate, the selected bestmove ensures strict decreasingness of distance to mate, or -- if that generates an engine that is too strong and detects long mate sequences that are non-trivial -- heuristically check for simple endgames and activate that strict decreasingness only in that case.

Expected behavior

Even on the lowest strength level (ELO 1300) Stockfish should be able to do simple checkmates like RK vs K.

Steps to reproduce

Stockfish 17.1 by the Stockfish developers (see AUTHORS file)
uci
id name Stockfish 17.1
id author the Stockfish developers (see AUTHORS file)

option name Debug Log File type string default <empty>
option name NumaPolicy type string default auto
option name Threads type spin default 1 min 1 max 1024
option name Hash type spin default 16 min 1 max 33554432
option name Clear Hash type button
option name Ponder type check default false
option name MultiPV type spin default 1 min 1 max 256
option name Skill Level type spin default 20 min 0 max 20
option name Move Overhead type spin default 10 min 0 max 5000
option name nodestime type spin default 0 min 0 max 10000
option name UCI_Chess960 type check default false
option name UCI_LimitStrength type check default false
option name UCI_Elo type spin default 1320 min 1320 max 3190
option name UCI_ShowWDL type check default false
option name SyzygyPath type string default <empty>
option name SyzygyProbeDepth type spin default 1 min 1 max 100
option name Syzygy50MoveRule type check default true
option name SyzygyProbeLimit type spin default 7 min 0 max 7
option name EvalFile type string default nn-1c0000000000.nnue
option name EvalFileSmall type string default nn-37f18f62d772.nnue
uciok
setoption type UCI_LimitStrength value true
setoption type UCI_Elo value 1600
position fen R7/8/8/3k4/8/8/8/K7 w - - 0 1
go movetime 1000
info string Available processors: 0-3
info string Using 1 thread
info string NNUE evaluation using nn-1c0000000000.nnue (133MiB, (22528, 3072, 15, 32, 1))
info string NNUE evaluation using nn-37f18f62d772.nnue (6MiB, (22528, 128, 15, 32, 1))
info depth 1 seldepth 3 multipv 1 score cp 514 nodes 66 nps 22000 hashfull 0 tbhits 0 time 3 pv a1b1
info depth 2 seldepth 3 multipv 1 score cp 515 nodes 314 nps 78500 hashfull 0 tbhits 0 time 4 pv a1b1 d5d6
info depth 3 seldepth 5 multipv 1 score cp 511 nodes 453 nps 90600 hashfull 0 tbhits 0 time 5 pv a8f8
info depth 4 seldepth 5 multipv 1 score cp 514 nodes 688 nps 114666 hashfull 0 tbhits 0 time 6 pv a1b1
info depth 5 seldepth 7 multipv 1 score cp 526 nodes 993 nps 141857 hashfull 0 tbhits 0 time 7 pv a8d8 d5e5 d8d1
info depth 6 seldepth 7 multipv 1 score cp 555 nodes 1559 nps 194875 hashfull 0 tbhits 0 time 8 pv a8e8 d5c4 e8e1
info depth 7 seldepth 7 multipv 1 score cp 562 nodes 2364 nps 262666 hashfull 0 tbhits 0 time 9 pv a8e8 d5c4 e8e1 c4d3 e1g1 d3e2
info depth 8 seldepth 11 multipv 1 score cp 547 nodes 3543 nps 322090 hashfull 0 tbhits 0 time 11 pv a1b1 d5d4 a8d8 d4e3 d8d1
info depth 9 seldepth 11 multipv 1 score cp 555 nodes 6132 nps 438000 hashfull 0 tbhits 0 time 14 pv a1b1 d5d4 a8d8 d4e3 d8d6 e3f4 d6d1
info depth 10 seldepth 15 multipv 1 score cp 536 nodes 9812 nps 545111 hashfull 0 tbhits 0 time 18 pv a8d8 d5e4 d8d6 e4e3 a1b1 e3f4 d6d1 f4f3
info depth 11 seldepth 17 multipv 1 score cp 543 nodes 13309 nps 578652 hashfull 0 tbhits 0 time 23 pv a8e8 d5c4 a1b1 c4d3 b1c1 d3d4 c1d1 d4d3
info depth 12 seldepth 13 multipv 1 score cp 555 nodes 22249 nps 695281 hashfull 1 tbhits 0 time 32 pv a8e8 d5c4 a1b1 c4d3 b1c1 d3d4 e8e2 d4d3 e2f2 d3e3 f2h2
info depth 13 seldepth 21 multipv 1 score cp 516 nodes 36942 nps 839590 hashfull 3 tbhits 0 time 44 pv a8a4 d5c5 a1b1 c5d5 a4f4 d5e5 f4f1 e5e4 f1e1 e4d3
info depth 14 seldepth 18 multipv 1 score cp 531 nodes 52250 nps 933035 hashfull 4 tbhits 0 time 56 pv a8a2 d5e4 a1b1 e4e3 b1c1 e3f3 c1d1 f3f4 d1e1
info depth 15 seldepth 15 multipv 1 score cp 531 nodes 84846 nps 1047481 hashfull 8 tbhits 0 time 81 pv a8e8 d5d4 a1b1 d4d3 b1c1 d3d4 c1d1 d4d3 e8e2 d3d4 e2d2 d4e4
info depth 16 seldepth 27 multipv 1 score cp 465 nodes 138816 nps 1128585 hashfull 14 tbhits 0 time 123 pv a8a4 d5e5 a1b2 e5f5 b2b1 f5e5 b1c1 e5d5 c1d2 d5e5 d2e1 e5d5 e1f1
info depth 17 seldepth 30 multipv 1 score cp 465 nodes 396967 nps 1364147 hashfull 52 tbhits 0 time 291 pv a8e8 d5d4 a1b1 d4d3 b1c1 d3d4 c1c2 d4d5 c2c3 d5d6 e8e2 d6d5 e2e1 d5c6 c3d4 c6b5 e1h1 b5b4 d4d3 b4c5 h1d1
info depth 18 seldepth 39 multipv 1 score cp 452 nodes 551272 nps 1477941 hashfull 59 tbhits 0 time 373 pv a8d8 d5e4 a1b2 e4e5 b2c2 e5e6 d8d2 e6e5 c2d1 e5e4 d1e2 e4f4 d2d8 f4e5 e2f2 e5e4
info depth 19 seldepth 40 multipv 1 score cp 458 nodes 615935 nps 1520827 hashfull 61 tbhits 0 time 405 pv a8c8 d5d6 c8d8 d6e5 a1b2 e5e4 b2b1 e4e3 b1c2 e3e4 c2c3 e4e5 c3d2 e5e4 d2e1 e4e3 d8d2 e3e4 e1f2 e4e5 f2f3 e5e6 f3f4 e6f6 d2e2 f6g6 f4g3 g6f5 g3h2 f5f4 e2e8
info depth 20 seldepth 37 multipv 1 score cp 466 nodes 852064 nps 1586711 hashfull 78 tbhits 0 time 537 pv a8e8 d5d4 a1b2 d4d3 b2b3 d3d2 b3c4 d2c2 e8d8 c2b2 d8c8 b2c2
info depth 21 seldepth 40 multipv 1 score cp 635 nodes 1129384 nps 1680630 hashfull 88 tbhits 0 time 672 pv a8e8 d5d4 a1b2 d4d3 b2c1 d3c4 c1d2 c4b5 d2c3 b5a6 e8e1 a6a7 c3b3 a7a8 e1e2
info depth 22 seldepth 40 multipv 1 score cp 642 nodes 1200123 nps 1697486 hashfull 89 tbhits 0 time 707 pv a8e8 d5d4 a1b2 d4d3 b2c1 d3c4 c1d2 c4b5 d2c3 b5c6 c3b3 c6b5 e8e2 b5a5 e2c2 a5b5 c2c1 b5a5 b3a3
info depth 23 seldepth 46 multipv 1 score mate 20 nodes 1320807 nps 1717564 hashfull 94 tbhits 0 time 769 pv a8e8 d5d4 a1b2 d4d3 b2c1 d3c4 c1d2 c4b3 e8c8 b3b4 d2c2 b4a3 c2c3 a3a4 c3b2 a4b4 c8c1 b4a4 b2c3 a4b5 c3b3 b5a6 b3b4 a6b6 c1c2 b6a7 b4b5 a7b7 c2d2 b7c7 d2d1 c7b7 d1c1 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 24 seldepth 46 multipv 1 score mate 23 nodes 1506853 nps 1740015 hashfull 99 tbhits 0 time 866 pv a8e8 d5d4 a1b2 d4d3 b2c1 d3c4 c1d2 c4b3 e8b8 b3c4 b8d8 c4b3 d8c8 b3b4 d2c2 b4a3 c2c3 a3a4 c8d8 a4b5 d8d1 b5a6 c3b4 a6b6 d1d2 b6a6 b4b3 a6a5 d2c2 a5b5 c2c1 b5a5 b3c4 a5b6 c4b4 b6a7 b4a5 a7b7 a5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 25 seldepth 44 multipv 1 score mate 22 nodes 1691940 nps 1691940 hashfull 104 tbhits 0 time 1000 pv a8e8 d5d4 a1b2 d4d3 b2c1 d3c4 c1d2 c4b3 e8c8 b3b4 d2c2 b4a3 c8b8 a3a4 b8d8 a4b4 c2b2 b4c4 d8d2 c4b5 b2b3 b5c5 d2d1 c5c6 b3c4 c6b6 c4b4 b6c6 d1d2 c6b7 d2c2 b7b6 c2c1 b6a7 b4a5 a7b7 a5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
bestmove a8f8 ponder d5e4
position fen 5R2/8/8/8/4k3/8/8/K7 w - - 2 2
go movetime 1000
info string Available processors: 0-3
info string Using 1 thread
info string NNUE evaluation using nn-1c0000000000.nnue (133MiB, (22528, 3072, 15, 32, 1))
info string NNUE evaluation using nn-37f18f62d772.nnue (6MiB, (22528, 128, 15, 32, 1))
info depth 1 seldepth 3 multipv 1 score cp 584 nodes 73 nps 36500 hashfull 0 tbhits 0 time 2 pv f8e8 e4f5
info depth 2 seldepth 3 multipv 1 score cp 579 nodes 186 nps 62000 hashfull 0 tbhits 0 time 3 pv f8e8 e4f5
info depth 3 seldepth 4 multipv 1 score cp 570 nodes 360 nps 90000 hashfull 0 tbhits 0 time 4 pv f8e8 e4f5 a1b2
info depth 4 seldepth 6 multipv 1 score cp 585 nodes 521 nps 130250 hashfull 0 tbhits 0 time 4 pv f8e8 e4d3
info depth 5 seldepth 8 multipv 1 score cp 562 nodes 704 nps 140800 hashfull 0 tbhits 0 time 5 pv f8e8 e4f3 a1b2
info depth 6 seldepth 8 multipv 1 score cp 565 nodes 963 nps 160500 hashfull 0 tbhits 0 time 6 pv f8e8 e4f3 a1b2 f3f4 b2c2 f4g4 c2d1
info depth 7 seldepth 8 multipv 1 score cp 571 nodes 1354 nps 193428 hashfull 0 tbhits 0 time 7 pv f8e8 e4f3 a1b2 f3f4 b2c2 f4g4 c2d1
info depth 8 seldepth 12 multipv 1 score cp 567 nodes 2034 nps 226000 hashfull 0 tbhits 0 time 9 pv f8e8 e4f3 a1b2 f3f4 b2c2 f4g4 c2d1
info depth 9 seldepth 30 multipv 1 score cp 584 nodes 3519 nps 351900 hashfull 0 tbhits 0 time 10 pv f8e8 e4f3 a1b2 f3f4 b2c2 f4g4 c2d1 g4f4 d1d2
info depth 10 seldepth 44 multipv 1 score cp 607 nodes 6076 nps 467384 hashfull 0 tbhits 0 time 13 pv a1b2 e4d3 f8e8 d3d2 e8d8 d2e2 b2c1 e2f2 d8e8 f2f3 c1d2 f3f4 d2e1 f4g5
info depth 11 seldepth 42 multipv 1 score cp 636 nodes 9713 nps 571352 hashfull 0 tbhits 0 time 17 pv f8e8 e4d3 a1b1 d3d2 e8d8 d2e2 b1b2 e2f2 b2c1
info depth 12 seldepth 48 multipv 1 score cp 629 nodes 14281 nps 649136 hashfull 1 tbhits 0 time 22 pv f8d8 e4e3 a1b2 e3e2 b2c1 e2f2 d8e8 f2g1 c1d2
info depth 13 seldepth 52 multipv 1 score cp 616 nodes 22267 nps 767827 hashfull 2 tbhits 0 time 29 pv a1b2 e4e3 f8d8 e3e2 b2c3 e2f3 d8e8 f3f4 c3c2 f4g4 e8f8 g4g5 c2d1 g5h6 f8e8 h6g6 e8e2
info depth 14 seldepth 50 multipv 1 score cp 628 nodes 38898 nps 972450 hashfull 3 tbhits 0 time 40 pv f8d8 e4e3 a1b2 e3e2 b2c1 e2f2 d8e8 f2f3 c1d1 f3f2 d1c2 f2f3 c2d2 f3f2 e8f8 f2g3 d2d1 g3g2 d1e1 g2h2 e1f2
info depth 15 seldepth 48 multipv 1 score cp 644 nodes 43281 nps 983659 hashfull 3 tbhits 0 time 44 pv f8d8 e4e3 a1b2 e3e2 b2c3 e2f3 d8e8 f3g4 c3c2 g4h4 e8g8 h4h5 g8g2 h5h6 c2b1
info depth 16 seldepth 48 multipv 1 score cp 652 nodes 68242 nps 1083206 hashfull 4 tbhits 0 time 63 pv f8e8 e4d3 a1b1 d3d2 e8d8 d2e2 b1c1 e2e3 c1c2 e3e4 c2d2 e4e5 d8e8 e5d4 d2c2 d4d5 c2c3 d5d6 c3c4 d6c7 e8e1 c7d6 e1e2 d6c7 c4c5 c7b7 c5b5 b7c8 e2e1
info depth 17 seldepth 50 multipv 1 score mate 23 nodes 110583 nps 1215197 hashfull 7 tbhits 0 time 91 pv a1b2 e4d3 f8d8 d3e3 b2c2 e3e4 d8e8 e4f4 c2d2 f4f3 d2e1 f3g3 e8f8 g3g2 e1e2 g2g3 e2e3 g3g4 e3f2 g4h4 f8g8 h4h3 f2g1 h3h4 g1g2 h4h5 g2g3 h5h6 g3h4 h6h7 g8g3 h7h8 g3g1 h8h7 h4g5 h7g7 g1f1 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 18 seldepth 50 multipv 1 score mate 23 nodes 154695 nps 1278471 hashfull 10 tbhits 0 time 121 pv f8e8 e4d3 a1b2 d3d2 e8d8 d2e3 b2c2 e3f4 d8e8 f4g4 c2d1 g4f3 d1d2 f3f4 d2e2 f4g4 e2f2 g4f4 f2g2 f4f5 g2g3 f5g5 e8f8 g5h5 f8f1 h5g5 f1f2 g5h5 g3f4 h5g6 f4g4 g6h7 g4f5 h7h6 f2f1 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 19 seldepth 50 multipv 1 score mate 24 nodes 215436 nps 1346475 hashfull 13 tbhits 0 time 160 pv a1b2 e4d3 f8d8 d3e3 b2c3 e3e4 c3c2 e4e3 d8e8 e3f4 c2d1 f4f3 d1d2 f3f2 e8f8 f2g3 d2e3 g3g4 f8e8 g4g5 e3f3 g5f5 f3g3 f5g5 e8e2 g5f5 e2e1 f5g6 g3f4 g6f6 f4g4 f6g7 e1f1 g7g6 f1f2 g6h7 g4g5 h7g7 f2f1 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 20 seldepth 48 multipv 1 score mate 22 nodes 339939 nps 1510840 hashfull 20 tbhits 0 time 225 pv a1b2 e4d3 f8d8 d3e4 b2c2 e4f5 d8e8 f5f4 c2d2 f4f3 d2e1 f3g3 e1e2 g3g4 e2e3 g4g5 e8e4 g5f5 e3f3 f5g5 e4e2 g5h4 e2f2 h4g5 f3g3 g5h6 g3f4 h6h5 f2f1 h5g6 f4g4 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 21 seldepth 50 multipv 1 score mate 22 nodes 398280 nps 1568031 hashfull 23 tbhits 0 time 254 pv f8d8 e4f4 a1b2 f4g4 d8f8 g4g5 f8e8 g5f6 b2c1 f6f7 e8e4 f7g6 c1d2 g6f5 d2e3 f5g5 e3f3 g5f5 e4e8 f5g5 e8f8 g5h4 f8g8 h4h5 f3f4 h5h6 g8g2 h6h5 g2g1 h5h6 f4f5 h6h7 f5g5 h7g7 g1f1 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 22 seldepth 50 multipv 1 score mate 21 nodes 435859 nps 1590726 hashfull 23 tbhits 0 time 274 pv f8d8 e4f4 a1b2 f4g4 d8f8 g4g5 b2c2 g5g6 c2d2 g6g7 f8f2 g7g6 d2e3 g6g5 f2f8 g5g4 e3f2 g4h3 f8g8 h3h4 f2f3 h4h5 f3f4 h5h6 g8g1 h6h5 g1f1 h5g6 f4g4 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 23 seldepth 42 multipv 1 score mate 21 nodes 461645 nps 1597387 hashfull 25 tbhits 0 time 289 pv f8d8 e4f4 a1b2 f4g4 d8f8 g4g5 b2c2 g5g6 c2d2 g6g7 f8f2 g7g6 d2e3 g6g5 f2f8 g5g4 e3f2 g4h3 f8g8 h3h4 f2f3 h4h5 f3f4 h5h6 g8g1 h6h5 g1f1 h5g6 f4g4 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 24 seldepth 40 multipv 1 score mate 20 nodes 490021 nps 1606626 hashfull 26 tbhits 0 time 305 pv a1b2 e4d3 f8d8 d3e3 b2c2 e3f4 d8e8 f4g4 c2d3 g4f3 e8f8 f3g3 d3e3 g3g4 e3f2 g4h3 f8g8 h3h4 f2f3 h4h5 f3f4 h5h6 g8g1 h6h5 g1f1 h5g6 f4g4 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 25 seldepth 46 multipv 1 score mate 20 nodes 613332 nps 1666663 hashfull 31 tbhits 0 time 368 pv a1b1 e4d3 f8e8 d3d2 b1b2 d2d3 b2c1 d3c4 e8d8 c4c3 c1b1 c3b3 d8c8 b3a3 b1c2 a3b4 c2b2 b4a4 b2c3 a4b5 c3b3 b5a5 b3c4 a5a6 c4b4 a6b7 c8c2 b7b6 c2c1 b6a7 b4b5 a7b7 c1c2 b7a7 b5c6 a7a8 c6c7 a8a7 c2a2
info depth 26 seldepth 50 multipv 1 score mate 21 nodes 745508 nps 1717760 hashfull 33 tbhits 0 time 434 pv a1b1 e4e3 b1c2 e3e4 f8e8 e4f4 c2d3 f4f3 e8f8 f3g3 d3d2 g3g4 d2e3 g4g5 e3f3 g5h4 f3g2 h4g4 f8f1 g4h5 g2f3 h5g5 f3g3 g5h6 g3f4 h6h5 f1g1 h5h6 f4f5 h6h7 f5g5 h7g7 g1f1 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 27 seldepth 48 multipv 1 score mate 20 nodes 924150 nps 1784073 hashfull 38 tbhits 0 time 518 pv f8e8 e4f4 a1b2 f4f3 b2c1 f3f2 c1d2 f2f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h5 g3f4 h5h6 f4g4 h6h7 f8f2 h7g6 f2f1 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 28 seldepth 40 multipv 1 score mate 19 nodes 1094552 nps 1839583 hashfull 45 tbhits 0 time 595 pv f8e8 e4f5 a1b1 f5g5 b1c2 g5f6 c2d2 f6f7 e8e4 f7f6 d2e3 f6g5 e3f3 g5f5 e4e2 f5g5 f3g3 g5f5 e2e1 f5g5 e1f1 g5h5 g3f4 h5g6 f4g4 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 29 seldepth 50 multipv 1 score mate 19 nodes 1330238 nps 1889542 hashfull 51 tbhits 0 time 704 pv a1b1 e4e5 b1c2 e5e4 f8e8 e4f3 c2d3 f3f4 d3e2 f4g4 e8f8 g4g3 e2d2 g3g4 d2e3 g4g3 f8g8 g3h4 e3f4 h4h3 f4f3 h3h4 g8g1 h4h5 f3f4 h5h6 f4f5 h6h7 f5f6 h7h8 f6g6 h8g8 g1e1 g8f8 e1e2 f8g8 e2e8
info depth 30 seldepth 50 multipv 1 score mate 19 nodes 1601650 nps 1936698 hashfull 59 tbhits 0 time 827 pv a1b1 e4e5 b1c2 e5e4 f8e8 e4f3 c2d2 f3f4 d2e2 f4g4 e8f8 g4g3 e2d2 g3g4 d2e3 g4g3 f8g8 g3h4 e3f4 h4h3 f4f3 h3h4 g8g1 h4h5 f3f4 h5h6 f4f5 h6h7 f5f6 h7h8 f6g6 h8g8 g1e1 g8f8 e1e2 f8g8 e2e8
info depth 31 seldepth 42 multipv 1 score mate 19 nodes 1870009 nps 1987257 hashfull 65 tbhits 0 time 941 pv a1b1 e4e5 b1c2 e5e4 f8e8 e4f3 c2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5f6 e8e2 f6f5 e2e1 f5g5 e1f1 g5h6 g3g4 h6g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 32 seldepth 48 multipv 1 score mate 19 nodes 2000589 nps 2000589 hashfull 66 tbhits 0 time 1000 pv a1b1 e4d3 f8e8 d3d2 b1b2 d2d3 b2b3 d3d4 b3c2 d4d5 c2c3 d5d6 e8e1 d6d5 e1e2 d5c5 e2d2 c5b5 c3b3 b5c5 d2d1 c5b6 b3b4 b6c6 d1d2 c6b7 b4b5 b7c7 d2d1 c7b7 d1c1 b7a7 b5c6 a7b8 c6b6 b8a8 c1c8
bestmove a1b2 ponder e4d3
position fen 5R2/8/8/8/3k4/8/1K6/8 w - - 4 3
go movetime 1000
info string Available processors: 0-3
info string Using 1 thread
info string NNUE evaluation using nn-1c0000000000.nnue (133MiB, (22528, 3072, 15, 32, 1))
info string NNUE evaluation using nn-37f18f62d772.nnue (6MiB, (22528, 128, 15, 32, 1))
info depth 1 seldepth 4 multipv 1 score cp 560 nodes 97 nps 32333 hashfull 0 tbhits 0 time 3 pv f8a8
info depth 2 seldepth 5 multipv 1 score cp 594 nodes 454 nps 113500 hashfull 0 tbhits 0 time 4 pv f8b8 d4d3
info depth 3 seldepth 5 multipv 1 score cp 585 nodes 630 nps 126000 hashfull 0 tbhits 0 time 5 pv b2b1 d4e4 f8e8 e4f3
info depth 4 seldepth 6 multipv 1 score cp 615 nodes 977 nps 162833 hashfull 0 tbhits 0 time 6 pv f8e8 d4d3 b2c1 d3d4
info depth 5 seldepth 7 multipv 1 score cp 585 nodes 1355 nps 225833 hashfull 0 tbhits 0 time 6 pv f8e8 d4d3 b2b1 d3d2 e8d8 d2e3
info depth 6 seldepth 7 multipv 1 score cp 610 nodes 1958 nps 244750 hashfull 0 tbhits 0 time 8 pv b2b1 d4e4 f8e8 e4f3
info depth 7 seldepth 9 multipv 1 score cp 603 nodes 2856 nps 317333 hashfull 0 tbhits 0 time 9 pv f8e8 d4d3 b2b1 d3d2 e8d8 d2e3
info depth 8 seldepth 13 multipv 1 score cp 607 nodes 5029 nps 457181 hashfull 0 tbhits 0 time 11 pv b2a1 d4e5 f8e8 e5f6 a1b1 f6f7
info depth 9 seldepth 46 multipv 1 score cp 602 nodes 7969 nps 569214 hashfull 0 tbhits 0 time 14 pv f8e8 d4d3 e8e1 d3d4 e1e6 d4d3 b2c1 d3c3 e6e1
info depth 10 seldepth 36 multipv 1 score cp 620 nodes 13198 nps 733222 hashfull 0 tbhits 0 time 18 pv f8c8 d4e4 b2c2 e4e5 c8e8 e5d5 c2c3 d5d6 e8e1 d6d5 e1e2 d5c5 e2d2 c5b5 c3b3 b5b6
info depth 11 seldepth 38 multipv 1 score cp 607 nodes 23572 nps 841857 hashfull 1 tbhits 0 time 28 pv b2c2 d4e5 f8e8 e5f4 c2d2 f4f3 d2e1 f3g3
info depth 12 seldepth 46 multipv 1 score cp 753 nodes 52919 nps 1125936 hashfull 4 tbhits 0 time 47 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4d5 e8e2 d5c4 e2d2 c4b4 c2b2 b4c4 d2d1 c4b4 d1c1 b4a5
info depth 13 seldepth 46 multipv 1 score mate 21 nodes 138694 nps 1400949 hashfull 10 tbhits 0 time 99 pv b2c2 d4e5 f8e8 e5f5 c2c3 f5f4 c3d2 f4f3 d2e1 f3g3 e8f8 g3g2 e1d2 g2g3 d2d3 g3g4 d3e3 g4g5 e3f3 g5g6 f3g4 g6g7 f8f2 g7g6 f2f1 g6h7 g4g5 h7g7 f1e1 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 14 seldepth 46 multipv 1 score mate 22 nodes 203415 nps 1564730 hashfull 11 tbhits 0 time 130 pv b2c2 d4e5 c2d2 e5d5 f8d8 d5e6 d8e8 e6f7 e8e4 f7f6 d2e3 f6g5 e3f3 g5f5 e4e8 f5g5 e8f8 g5g6 f3g3 g6h5 f8f2 h5g5 f2f1 g5h6 g3f4 h6g6 f4g4 g6h7 g4g5 h7g7 f1e1 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 15 seldepth 48 multipv 1 score mate 22 nodes 342797 nps 1731297 hashfull 14 tbhits 0 time 198 pv b2c2 d4e5 c2d2 e5d5 f8d8 d5e6 d8e8 e6f7 e8e4 f7f6 d2e3 f6g5 e3f3 g5f5 e4e8 f5g5 e8f8 g5g6 f3g3 g6h5 f8f2 h5g5 f2f1 g5h6 g3f4 h6g6 f4g4 g6h7 g4g5 h7g7 f1e1 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 16 seldepth 48 multipv 1 score mate 21 nodes 400340 nps 1763612 hashfull 15 tbhits 0 time 227 pv b2c1 d4e3 c1c2 e3e4 f8e8 e4f3 c2d3 f3f4 d3e2 f4g4 e8e4 g4g5 e2f3 g5f5 e4e8 f5g5 f3g3 g5g6 g3g4 g6g7 e8e2 g7f6 e2e1 f6g6 e1f1 g6h7 g4g5 h7g7 f1e1 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 17 seldepth 48 multipv 1 score mate 20 nodes 510916 nps 1818206 hashfull 17 tbhits 0 time 281 pv b2c2 d4e5 f8e8 e5d4 c2d2 d4c4 e8d8 c4b4 d2c2 b4c4 c2b2 c4b4 d8d2 b4c4 d2d1 c4b5 d1c1 b5b4 c1c2 b4a4 b2c3 a4b5 c3b3 b5a6 b3b4 a6b6 c2c1 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6b6 a8b8 c1c2 b8a8 c2c8
info depth 18 seldepth 52 multipv 1 score mate 20 nodes 575608 nps 1793171 hashfull 18 tbhits 0 time 321 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4c4 e8d8 c4b4 d8d1 b4c4 c2b2 c4b5 b2c3 b5a4 d1d8 a4b5 c3b3 b5b6 b3c4 b6a6 d8d2 a6b6 d2d1 b6c6 c4b4 c6b6 d1c1 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6b6 a8b8 c1c2 b8a8 c2c8
info depth 19 seldepth 48 multipv 1 score mate 21 nodes 605355 nps 1700435 hashfull 19 tbhits 0 time 356 pv b2c2 d4e4 c2c3 e4e5 f8e8 e5f4 c3d3 f4f3 d3d2 f3g3 e8f8 g3g4 d2e3 g4g5 e3f3 g5g6 f3g4 g6g7 f8f2 g7h7 f2f1 h7g6 g4h4 g6h6 f1g1 h6h7 h4g5 h7g7 g1e1 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 20 seldepth 42 multipv 1 score mate 20 nodes 617651 nps 1655900 hashfull 19 tbhits 0 time 373 pv f8e8 d4d3 b2c1 d3c3 e8d8 c3b3 d8d3 b3b4 c1c2 b4c4 d3d2 c4b4 d2d1 b4c4 c2b2 c4b5 b2b3 b5c5 d1d2 c5b5 d2c2 b5a6 b3c4 a6a5 c2c1 a5b6 c4b4 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6b6 a8b8 c1c2 b8a8 c2c8
info depth 21 seldepth 42 multipv 1 score mate 21 nodes 631572 nps 1615273 hashfull 19 tbhits 0 time 391 pv f8e8 d4d3 b2c1 d3c3 e8d8 c3b3 d8d3 b3b4 c1c2 b4c4 d3d2 c4b4 c2b2 b4c4 d2d1 c4b5 d1c1 b5b4 c1c2 b4a4 b2c3 a4b5 c3b3 b5a6 b3c4 a6a5 c2c1 a5b6 c4b4 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6b6 a8b8 c1c2 b8a8 c2c8
info depth 22 seldepth 46 multipv 1 score mate 18 nodes 713920 nps 1518978 hashfull 23 tbhits 0 time 470 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4c5 e8d8 c5c4 d8d2 c4b4 c2b2 b4c4 d2d1 c4b5 b2b3 b5c5 d1d2 c5b5 d2c2 b5a6 b3c4 a6a5 c2c1 a5b6 c4b4 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 23 seldepth 40 multipv 1 score mate 20 nodes 903457 nps 1585012 hashfull 32 tbhits 0 time 570 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4c4 e8d8 c4b4 d8d1 b4c4 c2b2 c4b4 d1c1 b4a4 c1c2 a4b4 c2c8 b4a4 b2c3 a4b5 c3b3 b5a5 c8c2 a5b5 c2c1 b5b6 b3b4 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6b6 a8b8 c1c2 b8a8 c2c8
info depth 24 seldepth 38 multipv 1 score mate 19 nodes 933036 nps 1592211 hashfull 33 tbhits 0 time 586 pv b2c2 d4e5 f8e8 e5d4 c2b2 d4d3 b2b3 d3d4 b3c2 d4c4 e8d8 c4b4 d8c8 b4a4 c2b2 a4b4 c8c1 b4a4 b2c3 a4b5 c3b3 b5a5 b3c4 a5a6 c4b4 a6b6 c1c2 b6a7 b4b5 a7b7 c2c1 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 25 seldepth 32 multipv 1 score mate 16 nodes 969078 nps 1601781 hashfull 34 tbhits 0 time 605 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4d5 c2c3 d5d6 c3c4 d6d7 e8e2 d7d6 e2e1 d6c6 e1d1 c6b6 d1d2 b6c6 c4b4 c6b6 d2c2 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c2a2
info depth 26 seldepth 34 multipv 1 score mate 16 nodes 1008590 nps 1608596 hashfull 36 tbhits 0 time 627 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4d5 c2c3 d5d6 c3c4 d6d7 e8e2 d7d6 e2e1 d6c6 e1d1 c6b6 d1d2 b6c6 c4b4 c6b6 d2c2 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c2a2
info depth 27 seldepth 34 multipv 1 score mate 16 nodes 1033388 nps 1612149 hashfull 36 tbhits 0 time 641 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4d5 c2c3 d5d6 c3c4 d6d7 e8e1 d7d6 e1e2 d6c6 e2d2 c6b6 d2d1 b6c6 c4b4 c6b6 d1c1 b6a7 b4b5 a7b7 c1c2 b7a7 b5c6 a7a8 c6c7 a8a7 c2a2
info depth 28 seldepth 34 multipv 1 score mate 16 nodes 1066928 nps 1619010 hashfull 38 tbhits 0 time 659 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4d5 c2c3 d5d6 c3c4 d6d7 e8e1 d7d6 e1e2 d6c6 e2d2 c6b6 c4b4 b6c6 d2d1 c6b6 d1c1 b6a7 b4b5 a7b7 c1c2 b7a7 b5c6 a7a8 c6c7 a8a7 c2a2
info depth 29 seldepth 32 multipv 1 score mate 16 nodes 1136492 nps 1635240 hashfull 39 tbhits 0 time 695 pv f8e8 d4d3 b2b3 d3d4 b3c2 d4d5 c2c3 d5d6 c3c4 d6d7 e8e1 d7d6 e1e2 d6c6 e2d2 c6b6 c4b4 b6c6 d2d1 c6b6 d1c1 b6a7 b4a5 a7b7 a5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 30 seldepth 34 multipv 1 score mate 16 nodes 1289840 nps 1596336 hashfull 44 tbhits 0 time 808 pv f8e8 d4d3 b2b3 d3d4 b3b4 d4d5 b4c3 d5d6 c3c4 d6d7 e8e1 d7d6 e1e2 d6c6 e2d2 c6b6 d2d6 b6c7 c4c5 c7b7 c5b5 b7a7 d6d1 a7b7 d1c1 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 31 seldepth 32 multipv 1 score mate 16 nodes 1439374 nps 1631943 hashfull 49 tbhits 0 time 882 pv f8e8 d4d3 b2b3 d3d4 b3b4 d4d5 b4c3 d5d6 c3c4 d6d7 e8e1 d7d6 e1e2 d6c6 e2d2 c6b6 d2d6 b6c7 c4c5 c7b7 c5b5 b7a7 d6d1 a7b7 d1c1 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 32 seldepth 32 multipv 1 score mate 15 nodes 1642345 nps 1674153 hashfull 55 tbhits 0 time 981 pv f8e8 d4d3 b2b3 d3d4 b3b4 d4d5 b4c3 d5d6 c3c4 d6d7 e8e1 d7d6 e1e2 d6c6 e2d2 c6b6 d2d6 b6c7 c4c5 c7b7 d6d7 b7c8 c5c6 c8b8 d7d2 b8a7 d2d8 a7a6 d8a8
info depth 33 seldepth 30 multipv 1 score mate 15 nodes 1677337 nps 1677337 hashfull 57 tbhits 0 time 1000 pv f8e8 d4d3 b2b3 d3d4 b3b4 d4d5 b4c3 d5d6 c3c4 d6d7 e8e1 d7d6 e1e2 d6c6 e2d2 c6b6 d2d6 b6c7 c4c5 c7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
bestmove b2b1 ponder d4d3
position fen 5R2/8/8/8/4k3/8/8/1K6 w - - 6 4
go movetime 1000
info string Available processors: 0-3
info string Using 1 thread
info string NNUE evaluation using nn-1c0000000000.nnue (133MiB, (22528, 3072, 15, 32, 1))
info string NNUE evaluation using nn-37f18f62d772.nnue (6MiB, (22528, 128, 15, 32, 1))
info depth 1 seldepth 4 multipv 1 score cp 614 nodes 101 nps 50500 hashfull 0 tbhits 0 time 2 pv f8h8
info depth 2 seldepth 4 multipv 1 score cp 600 nodes 458 nps 152666 hashfull 0 tbhits 0 time 3 pv f8h8 e4f4
info depth 3 seldepth 5 multipv 1 score cp 588 nodes 629 nps 209666 hashfull 0 tbhits 0 time 3 pv f8e8 e4d3
info depth 4 seldepth 5 multipv 1 score cp 594 nodes 927 nps 231750 hashfull 0 tbhits 0 time 4 pv b1c1 e4d4
info depth 5 seldepth 10 multipv 1 score cp 600 nodes 1462 nps 292400 hashfull 0 tbhits 0 time 5 pv b1c1 e4d4
info depth 6 seldepth 7 multipv 1 score cp 604 nodes 1897 nps 316166 hashfull 0 tbhits 0 time 6 pv f8e8 e4d3 b1c1 d3c4
info depth 7 seldepth 9 multipv 1 score cp 593 nodes 2408 nps 344000 hashfull 0 tbhits 0 time 7 pv f8e8 e4d3 b1c1 d3c4 e8d8
info depth 8 seldepth 13 multipv 1 score cp 563 nodes 3751 nps 468875 hashfull 0 tbhits 0 time 8 pv f8e8 e4d3 b1c1 d3c4 e8d8 c4c3 d8d1 c3b3 d1d2
info depth 9 seldepth 13 multipv 1 score cp 545 nodes 7459 nps 678090 hashfull 1 tbhits 0 time 11 pv f8e8 e4d3 b1c1 d3c4 e8d8 c4c3 d8d1 c3b3 d1d2 b3c3 d2d8
info depth 10 seldepth 42 multipv 1 score cp 551 nodes 12595 nps 787187 hashfull 1 tbhits 0 time 16 pv f8e8 e4d3 b1c1 d3c4 c1c2 c4d4 c2d2 d4c4 e8d8 c4b3 d2d3
info depth 11 seldepth 50 multipv 1 score cp 558 nodes 20336 nps 924363 hashfull 2 tbhits 0 time 22 pv f8e8 e4d3 b1c1 d3c4 c1d2 c4d4 d2c2 d4c4 e8d8 c4b4 d8d2 b4b5 c2b3
info depth 12 seldepth 38 multipv 1 score cp 645 nodes 32844 nps 1094800 hashfull 2 tbhits 0 time 30 pv f8e8 e4d3 b1c1 d3d4 c1c2 d4c4 e8d8 c4b4 d8d1 b4c4 c2b2 c4b4 d1c1 b4a4 b2c3 a4b5 c3b3 b5a5
info depth 13 seldepth 48 multipv 1 score cp 616 nodes 59495 nps 1293369 hashfull 4 tbhits 0 time 46 pv b1b2 e4d3 f8e8 d3d2 e8d8 d2e3 b2c1
info depth 14 seldepth 38 multipv 1 score cp 718 nodes 79404 nps 1323400 hashfull 4 tbhits 0 time 60 pv b1b2 e4d3 b2c1 d3d4 f8d8 d4c3 d8d1 c3b3 d1d3 b3c4 c1c2 c4b4 d3d1 b4c4 c2b2 c4b4 d1c1 b4a5
info depth 15 seldepth 48 multipv 1 score cp 1882 nodes 137977 nps 1452389 hashfull 9 tbhits 0 time 95 pv f8h8 e4e5 h8e8 e5d4 e8d8 d4e5 b1b2 e5f6 b2c3 f6e7 d8d3 e7f6
info depth 16 seldepth 46 multipv 1 score cp 4453 nodes 159266 nps 1474685 hashfull 10 tbhits 0 time 108 pv f8d8 e4f5 d8e8 f5f4 b1c2 f4g4 c2c1 g4f4 c1b2 f4f5 b2c3
info depth 17 seldepth 52 multipv 1 score mate 19 nodes 283895 nps 1568480 hashfull 14 tbhits 0 time 181 pv f8e8 e4f3 b1c1 f3f4 c1d2 f4f3 d2e1 f3g3 e8f8 g3g2 e1d2 g2g3 d2e2 g3g4 e2f2 g4g5 f2g3 g5g6 f8f2 g6g5 f2f1 g5h5 g3f4 h5g6 f4g4 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 18 seldepth 52 multipv 1 score mate 18 nodes 354921 nps 1658509 hashfull 17 tbhits 0 time 214 pv b1c2 e4d5 f8e8 d5d4 c2d2 d4c4 e8d8 c4b3 d8c8 b3b2 c8b8 b2a3 d2c2 a3a4 c2c3 a4a5 c3c4 a5a6 b8d8 a6b6 d8d6 b6c7 c4c5 c7b7 d6d1 b7a6 d1c1 a6b7 c5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 19 seldepth 36 multipv 1 score mate 18 nodes 386010 nps 1678304 hashfull 17 tbhits 0 time 230 pv b1c2 e4d5 f8e8 d5d4 c2d2 d4c4 e8d8 c4b3 d8c8 b3b2 c8b8 b2a3 d2c2 a3a4 c2c3 a4a5 c3c4 a5a6 b8d8 a6b6 d8d6 b6c7 c4c5 c7b7 d6d1 b7a6 d1c1 a6b7 c5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 20 seldepth 36 multipv 1 score mate 18 nodes 394032 nps 1676731 hashfull 18 tbhits 0 time 235 pv b1c2 e4d5 f8e8 d5d4 c2d2 d4c4 e8d8 c4b3 d8c8 b3b2 c8b8 b2a3 d2c2 a3a4 c2c3 a4a5 c3c4 a5a6 b8d8 a6b6 d8d6 b6c7 c4c5 c7b7 d6d1 b7a6 d1c1 a6b7 c5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 21 seldepth 50 multipv 1 score mate 18 nodes 481209 nps 1724763 hashfull 19 tbhits 0 time 279 pv b1c2 e4d5 f8e8 d5d4 c2d2 d4c4 e8d8 c4b3 d8c8 b3b2 c8b8 b2a3 d2c2 a3a4 c2c3 a4a5 c3c4 a5a6 b8d8 a6b6 d8d6 b6c7 c4c5 c7b7 d6d1 b7a6 d1c1 a6b7 c5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 22 seldepth 36 multipv 1 score mate 18 nodes 503655 nps 1730773 hashfull 20 tbhits 0 time 291 pv b1c2 e4d5 f8e8 d5d4 c2d2 d4c4 e8d8 c4b3 d8c8 b3b2 c8b8 b2a3 d2c2 a3a4 c2c3 a4a5 c3c4 a5a6 b8d8 a6b6 d8d6 b6c7 c4c5 c7b7 d6d1 b7a6 d1c1 a6b7 c5b5 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 23 seldepth 36 multipv 1 score mate 18 nodes 537192 nps 1732877 hashfull 21 tbhits 0 time 310 pv b1c2 e4d5 f8e8 d5d4 c2d2 d4c4 e8d8 c4b3 d8c8 b3b2 c8b8 b2a3 d2c2 a3a4 c2c3 a4a5 c3c4 a5a6 b8d8 a6b6 d8d2 b6a6 c4b4 a6b6 d2c2 b6a7 b4b5 a7b7 c2c1 b7a8 b5b6 a8b8 c1c2 b8a8 c2c8
info depth 24 seldepth 40 multipv 1 score mate 18 nodes 604750 nps 1737787 hashfull 24 tbhits 0 time 348 pv b1c2 e4d5 f8e8 d5d4 c2d2 d4c4 e8d8 c4b3 d8c8 b3b2 c8b8 b2a3 d2c2 a3a4 c2c3 a4a5 c3c4 a5a6 b8d8 a6b6 d8d2 b6a6 c4b4 a6b7 b4b5 b7c7 d2d1 c7b8 b5c6 b8a7 d1c1 a7a8 c6c7 a8a7 c1a1
info depth 25 seldepth 38 multipv 1 score mate 18 nodes 628890 nps 1742077 hashfull 24 tbhits 0 time 361 pv b1c2 e4e5 f8e8 e5f5 c2d2 f5f4 d2e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h5 f8f1 h5g5 f1f2 g5h6 g3g4 h6g6 f2f1 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 26 seldepth 44 multipv 1 score mate 18 nodes 651397 nps 1751067 hashfull 24 tbhits 0 time 372 pv b1c2 e4e3 f8e8 e3f3 c2d2 f3f4 d2e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h5 f8f1 h5g5 f1f2 g5h6 g3g4 h6g6 f2f1 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 27 seldepth 34 multipv 1 score mate 17 nodes 717418 nps 1767039 hashfull 28 tbhits 0 time 406 pv b1c2 e4e3 f8e8 e3f3 c2d2 f3f4 d2e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f2 g7g6 f2f1 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 28 seldepth 34 multipv 1 score mate 17 nodes 770532 nps 1712293 hashfull 29 tbhits 0 time 450 pv b1c2 e4e3 f8e8 e3f3 c2d2 f3f4 d2e2 f4g4 e8f8 g4g3 e2d2 g3g4 d2e3 g4g5 e3f3 g5h4 f8g8 h4h5 f3f4 h5h6 g8g3 h6h5 g3g1 h5h6 f4f5 h6h7 f5f6 h7h8 f6g6 h8g8 g1f1 g8h8 f1f8
info depth 29 seldepth 34 multipv 1 score mate 17 nodes 810269 nps 1660387 hashfull 31 tbhits 0 time 488 pv b1c2 e4e3 f8e8 e3f3 c2d2 f3f4 d2e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5g6 g3g4 g6g7 f8f2 g7g6 f2f1 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 30 seldepth 38 multipv 1 score mate 18 nodes 908671 nps 1646143 hashfull 34 tbhits 0 time 552 pv b1c2 e4e5 f8e8 e5f5 c2d3 f5f4 d3e2 f4g4 e8e4 g4g5 e2e3 g5f5 e3f3 f5g5 f3g3 g5h6 g3f4 h6g6 e4e1 g6f6 f4g4 f6g6 e1f1 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 31 seldepth 52 multipv 1 score mate 17 nodes 1013311 nps 1677667 hashfull 40 tbhits 0 time 604 pv b1c2 e4e5 f8e8 e5f5 c2d3 f5f4 d3e2 f4g4 e8f8 g4g3 e2d2 g3g4 d2e3 g4g5 e3f3 g5h6 f8g8 h6h7 g8g3 h7h6 g3g1 h6h5 f3f4 h5h6 f4f5 h6h7 f5f6 h7h8 f6g6 h8g8 g1f1 g8h8 f1f8
info depth 32 seldepth 44 multipv 1 score mate 18 nodes 1082896 nps 1692025 hashfull 43 tbhits 0 time 640 pv b1c2 e4e5 f8e8 e5f5 c2d3 f5f4 d3e2 f4g4 e2e3 g4g5 e8e5 g5f6 e3f4 f6g6 f4g4 g6h7 g4g5 h7g7 e5e1 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f2f1 h8h7 f1e1 h7g8 f6g6 g8f8 e1e2 f8g8 e2e8
info depth 33 seldepth 44 multipv 1 score mate 17 nodes 1185970 nps 1716309 hashfull 47 tbhits 0 time 691 pv b1c2 e4e5 f8e8 e5f5 c2d2 f5f4 d2d3 f4f5 d3e3 f5g5 e8e5 g5g6 e3f4 g6f6 e5e4 f6g6 f4g4 g6f6 e4e2 f6g7 g4g5 g7f7 e2e1 f7g7 e1f1 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 34 seldepth 34 multipv 1 score mate 17 nodes 1554362 nps 1682209 hashfull 67 tbhits 0 time 924 pv b1c2 e4e5 f8e8 e5f5 c2d2 f5f4 d2d3 f4f5 d3e3 f5g5 e8e5 g5g6 e3f4 g6f6 e5e4 f6g6 f4g4 g6f6 e4e2 f6g7 g4g5 g7f7 e2e1 f7g7 e1f1 g7h7 g5f6 h7h8 f6g6 h8g8 f1f2 g8h8 f2f8
info depth 35 seldepth 58 multipv 1 score mate 17 nodes 1708682 nps 1708682 hashfull 72 tbhits 0 time 1000 pv b1c2 e4e5 f8e8 e5f5 c2d2 f5f4 d2d3 f4f5 d3e3 f5g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5g6 g3g4 g6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
bestmove b1c1 ponder e4e3
position fen 5R2/8/8/8/3k4/8/8/2K5 w - - 8 5
go movetime 1000
info string Available processors: 0-3
info string Using 1 thread
info string NNUE evaluation using nn-1c0000000000.nnue (133MiB, (22528, 3072, 15, 32, 1))
info string NNUE evaluation using nn-37f18f62d772.nnue (6MiB, (22528, 128, 15, 32, 1))
info depth 1 seldepth 3 multipv 1 score cp 554 nodes 108 nps 36000 hashfull 0 tbhits 0 time 3 pv f8e8
info depth 2 seldepth 3 multipv 1 score cp 609 nodes 524 nps 104800 hashfull 0 tbhits 0 time 5 pv c1b1 d4e5
info depth 3 seldepth 6 multipv 1 score cp 607 nodes 652 nps 108666 hashfull 0 tbhits 0 time 6 pv f8d8 d4e4
info depth 4 seldepth 5 multipv 1 score cp 604 nodes 954 nps 136285 hashfull 0 tbhits 0 time 7 pv c1b1
info depth 5 seldepth 7 multipv 1 score cp 632 nodes 1251 nps 156375 hashfull 0 tbhits 0 time 8 pv c1b1 d4e5 f8e8 e5d4 e8e2 d4c3
info depth 6 seldepth 8 multipv 1 score cp 592 nodes 1679 nps 186555 hashfull 0 tbhits 0 time 9 pv f8e8 d4c4
info depth 7 seldepth 9 multipv 1 score cp 564 nodes 2525 nps 252500 hashfull 0 tbhits 0 time 10 pv f8c8 d4e5 c8e8 e5d4
info depth 8 seldepth 9 multipv 1 score cp 590 nodes 3714 nps 309500 hashfull 0 tbhits 0 time 12 pv f8e8 d4d3 c1d1 d3c4 e8d8 c4c3
info depth 9 seldepth 38 multipv 1 score cp 575 nodes 6550 nps 467857 hashfull 1 tbhits 0 time 14 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2f2 g4f4
info depth 10 seldepth 34 multipv 1 score cp 564 nodes 10738 nps 596555 hashfull 1 tbhits 0 time 18 pv c1d2 d4e4 f8e8 e4f3 e8e1
info depth 11 seldepth 46 multipv 1 score cp 567 nodes 17002 nps 739217 hashfull 2 tbhits 0 time 23 pv f8b8 d4e5 b8e8 e5d4 c1c2 d4c4 e8d8 c4b4 d8c8 b4a4 c2c3 a4b5 c3b3 b5a5 c8d8
info depth 12 seldepth 34 multipv 1 score cp 616 nodes 24103 nps 860821 hashfull 2 tbhits 0 time 28 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e8f8 g4g3 e2e3 g3g4 e3f2 g4h5
info depth 13 seldepth 42 multipv 1 score cp 607 nodes 31882 nps 937705 hashfull 3 tbhits 0 time 34 pv c1b1 d4e5 f8e8 e5d4 b1c2 d4c4 e8d8 c4b4 d8d1 b4c4 c2b2 c4b5 d1d8
info depth 14 seldepth 42 multipv 1 score cp 633 nodes 43495 nps 1011511 hashfull 4 tbhits 0 time 43 pv c1b1 d4e5 f8e8 e5d4 b1c2 d4c4 e8d8 c4b4 d8d1 b4c4 c2b2 c4b5 b2c3 b5c5 c3b3 c5b5 d1c1 b5a5
info depth 15 seldepth 46 multipv 1 score cp 646 nodes 62200 nps 1130909 hashfull 4 tbhits 0 time 55 pv c1d1 d4d5 f8e8 d5c4 d1c2 c4c5 c2c1 c5c6 e8d8 c6b7
info depth 16 seldepth 46 multipv 1 score mate 18 nodes 83666 nps 1195228 hashfull 5 tbhits 0 time 70 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8e2 g5f5 e2e1 f5g6 g3f4 g6f6 f4g4 f6g7 g4g5 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 17 seldepth 36 multipv 1 score mate 18 nodes 92768 nps 1204779 hashfull 5 tbhits 0 time 77 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8e2 g5f5 e2e1 f5g6 g3f4 g6f6 f4g4 f6g7 g4g5 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 18 seldepth 36 multipv 1 score mate 18 nodes 100234 nps 1207638 hashfull 7 tbhits 0 time 83 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8e2 g5f5 e2e1 f5g6 g3f4 g6f6 f4g4 f6g7 g4g5 g7f7 e1e2 f7g7 e2f2 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 19 seldepth 36 multipv 1 score mate 17 nodes 107542 nps 1208337 hashfull 7 tbhits 0 time 89 pv f8e8 d4d3 c1d1 d3c4 d1d2 c4d4 d2c2 d4c4 e8d8 c4b4 d8c8 b4a4 c2b2 a4b4 c8c1 b4a5 b2c3 a5b5 c3b3 b5a6 b3b4 a6b6 c1c2 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c2a2
info depth 20 seldepth 34 multipv 1 score mate 17 nodes 111021 nps 1206750 hashfull 7 tbhits 0 time 92 pv f8e8 d4d3 c1d1 d3c4 d1d2 c4d4 d2c2 d4c4 e8d8 c4b4 d8c8 b4a4 c2b2 a4b4 c8c1 b4a5 b2c3 a5b5 c3b3 b5a6 b3b4 a6b6 c1c2 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c2a2
info depth 21 seldepth 36 multipv 1 score mate 18 nodes 114992 nps 1197833 hashfull 7 tbhits 0 time 96 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d8c8 b3b2 d1d2 b2b3 d2d3 b3b4 d3c2 b4a4 c2b2 a4b4 c8c1 b4a5 b2c3 a5b5 c3b3 b5a6 b3a4 a6b6 a4b4 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 22 seldepth 36 multipv 1 score mate 18 nodes 118548 nps 1197454 hashfull 7 tbhits 0 time 99 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d8c8 b3b2 d1d2 b2b3 d2d3 b3b4 d3c2 b4a4 c2b2 a4b4 c8c1 b4a5 b2c3 a5b5 c3b3 b5a6 b3a4 a6b6 a4b4 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 23 seldepth 36 multipv 1 score mate 17 nodes 126136 nps 1167925 hashfull 8 tbhits 0 time 108 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3b4 d2d3 b4b5 d3c3 b5c5 c3b3 c5b5 d8d1 b5c5 d1d2 c5b5 d2c2 b5a6 b3b4 a6b6 c2c1 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 24 seldepth 36 multipv 1 score mate 18 nodes 138468 nps 1183487 hashfull 8 tbhits 0 time 117 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3b4 d8c8 b4b3 d2d3 b3b4 d3c2 b4a4 c2b2 a4b4 c8c1 b4a5 b2c3 a5b5 c3b3 b5a6 b3a4 a6b6 a4b4 b6a6 b4c5 a6b7 c5b5 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 25 seldepth 38 multipv 1 score mate 17 nodes 149914 nps 1189793 hashfull 10 tbhits 0 time 126 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 26 seldepth 34 multipv 1 score mate 17 nodes 163560 nps 1211555 hashfull 12 tbhits 0 time 135 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 27 seldepth 34 multipv 1 score mate 17 nodes 174867 nps 1214354 hashfull 12 tbhits 0 time 144 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 28 seldepth 34 multipv 1 score mate 17 nodes 190830 nps 1231161 hashfull 13 tbhits 0 time 155 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 29 seldepth 34 multipv 1 score mate 17 nodes 210915 nps 1248017 hashfull 14 tbhits 0 time 169 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 30 seldepth 34 multipv 1 score mate 17 nodes 235641 nps 1273735 hashfull 15 tbhits 0 time 185 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 31 seldepth 34 multipv 1 score mate 17 nodes 254557 nps 1285641 hashfull 16 tbhits 0 time 198 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 32 seldepth 34 multipv 1 score mate 17 nodes 289724 nps 1305063 hashfull 22 tbhits 0 time 222 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 33 seldepth 34 multipv 1 score mate 17 nodes 425178 nps 1436412 hashfull 31 tbhits 0 time 296 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 34 seldepth 34 multipv 1 score mate 17 nodes 524853 nps 1512544 hashfull 36 tbhits 0 time 347 pv c1d2 d4e4 f8e8 e4f3 d2d3 f3f4 d3e2 f4g4 e2e3 g4g5 e3f3 g5f5 f3g3 f5g5 e8f8 g5h6 g3g4 h6g7 f8f1 g7g6 f1f2 g6h6 g4f5 h6g7 f5g5 g7h7 g5f6 h7h8 f6g6 h8g8 f2f1 g8h8 f1f8
info depth 35 seldepth 34 multipv 1 score mate 16 nodes 674866 nps 1513152 hashfull 45 tbhits 0 time 446 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3b4 d2d3 b4b5 d8d5 b5b6 d3c4 b6c6 d5d1 c6b6 c4b4 b6c6 d1d2 c6b7 b4b5 b7c7 d2d1 c7b7 d1c1 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 36 seldepth 40 multipv 1 score mate 16 nodes 836218 nps 1583746 hashfull 53 tbhits 0 time 528 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6c7 c4c5 c7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
info depth 37 seldepth 38 multipv 1 score mate 16 nodes 929076 nps 1607397 hashfull 57 tbhits 0 time 578 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6c7 c4c5 c7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
info depth 38 seldepth 34 multipv 1 score mate 16 nodes 1008756 nps 1621794 hashfull 61 tbhits 0 time 622 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6c7 c4c5 c7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
info depth 39 seldepth 32 multipv 1 score mate 16 nodes 1150948 nps 1648922 hashfull 71 tbhits 0 time 698 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6c7 c4c5 c7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
info depth 40 seldepth 34 multipv 1 score mate 16 nodes 1295245 nps 1675608 hashfull 75 tbhits 0 time 773 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6b7 c4b5 b7c7 d6d1 c7b7 d1c1 b7a7 b5c6 a7a8 c6c7 a8a7 c1a1
info depth 41 seldepth 32 multipv 1 score mate 16 nodes 1462128 nps 1653990 hashfull 81 tbhits 0 time 884 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6a7 c4c5 a7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
info depth 42 seldepth 32 multipv 1 score mate 16 nodes 1660742 nps 1680912 hashfull 94 tbhits 0 time 988 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6a7 c4c5 a7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
info depth 43 seldepth 32 multipv 1 score mate 16 nodes 1678540 nps 1678540 hashfull 97 tbhits 0 time 1000 pv f8e8 d4d3 c1d1 d3c3 e8d8 c3b3 d1d2 b3c4 d2c2 c4b4 d8d4 b4c5 c2c3 c5b5 d4d5 b5c6 c3c4 c6b6 d5d6 b6a7 c4c5 a7b7 d6d7 b7c8 c5c6 c8b8 c6b6 b8c8 d7d2 c8b8 d2d8
bestmove c1b1 ponder d4e3

Anything else?

No response

Operating system

All

Stockfish version

Stockfish 17.1

[87flowers]

Side-note: Providing a FEN for each new position is not ideal, because that destroys three-fold repetition information.

You should instead:

position fen R7/8/8/3k4/8/8/8/K7 w - - 0 1
go movetime 1000
position fen R7/8/8/3k4/8/8/8/K7 w - - 0 1 moves a1b1 d5d4
go movetime 1000
position fen R7/8/8/3k4/8/8/8/K7 w - - 0 1 moves a1b1 d5d4 b1b2 d4c5
go movetime 1000
position fen R7/8/8/3k4/8/8/8/K7 w - - 0 1 moves a1b1 d5d4 b1b2 d4c5 a8d8 c5c6
go movetime 1000
position fen R7/8/8/3k4/8/8/8/K7 w - - 0 1 moves a1b1 d5d4 b1b2 d4c5 a8d8 c5c6 d8d1 c6c5
go movetime 1000
...

[dav1312]

Tested it with the position that you used (R7/8/8/3k4/8/8/8/K7 w - - 0 1).
1600 Elo can't mate (0/80 games), but 3000 can (80/80 games).
So it all comes down to what you believe should be the minimum Elo at which a player should know how to mate with king and rook.

Setup used:

.\fastchess.exe `
-engine name="Stockfish 17.1" cmd="stockfish_17.1_x64_avx2.exe" `
-engine name="Stockfish 17.1 UCI_Elo 1600" cmd="stockfish_17.1_x64_avx2.exe" option.UCI_Elo=1600 option.UCI_LimitStrength=true `
-engine name="Stockfish 17.1 UCI_Elo 3000" cmd="stockfish_17.1_x64_avx2.exe" option.UCI_Elo=3000 option.UCI_LimitStrength=true `
-tournament gauntlet `
-openings file=.\books\KRvK.epd format=epd -noswap -reverse `
-each st=0.5 timemargin=50 `
-rounds 50 -concurrency 3

[asdfjkl]

I would imagine that limiting Elo usually is intended for playing against the engine. From my own expeirence - very subjective of course -, players with a rating of approx. 900 and above are able to checkmate with king and rook. Hence I would assume, that the expected behavior of most players playing against Stockfish is that even at the lowest possible setting of Elo 1320 Stockfish can mate with king and rook. The overall playing strength when playing with 1320 also does not fit with someone not being able to mate with rook and king.

[vdbergh]

Tested it with the position that you used (R7/8/8/3k4/8/8/8/K7 w - - 0 1). 1600 Elo can't mate (0/80 games), but 3000 can (80/80 games). So it all comes down to what you believe should be the minimum Elo at which a player should know how to mate with king and rook.

I am a weak player but I can easily mate with KR.

[Disservin]

The problem here is that we can't accurately mimic a human at a certain strength in stockfish. Any alpha beta engine playstyle vastly differs from human play. Engines will not hang a piece in one move, humans do.. at all skill levels.
The way we mimic strength is to pick a random move according to a distribution which over many games on average performs the same as an engine at that strength. This is the simplest approach we can choose. What this means is that sometimes a strength limited stockfish will play a move which only a grandmaster would play, and sometimes chooses a move which blunders completely, i.e. not recapturing a queen.
I don't think we will change the way this works any time soon.

[vondele]

I think the problem here is that SF can actually not mate with KRvK at very low depth. There is no particular logic for pushing the king to the edge. All positions are essentially 'won' and SF needs a deeper search to find a mate.

[dav1312]

As additional context, this seems to be the commit that introduced the time to pick = 1 + skill level
2e6839c

[RogerThiede]

This is illustrating a disconnect between what many users expect and how Stockfish actually behaves. Users generally interpret the UCI_Elo number as "play like a human of that rating". Treating UCI_Elo like a human emulation of that Elo is a misunderstanding.

One potential solution is to better educate users about UCI_LimitStrength and UCI_Elo because if we just close this issue as not a problem or close it as won't fix, it won't reduce repeated reports on UCI_Elo behavior continually being submitted in the future.
A much harder solution is to actually implement UCI_Elo in a manner that always reflects human play from a human at that Elo, but I worry this isn't in-line with any goals of the Stockfish developers.

Stockfish focuses on strength, and UCI_LimitStrength is a feature that can limit strength but limiting strength does not make it human-like and this needs to be communicated better. Such a solution may already exist in alternative engines that were made exclusively for that purpose which I usually see by using training data of human against human and engine against human, but essentially serve a purpose counter to the goals of Stockfish where the training data is engine against engine.

UCI_LimitStrength introduces a skill-dependent/probabilistic choice of the move after performing a normal search and this type of implementation would exacerbate that probabilistic choice to be worse and worse if the winning move required a consistent multi-move strategy like box-shrinking to mate with KR against K.

I think the problem here is that SF can actually not mate with KRvK at very low depth.

Are we sure that this is true regardless of UCI_LimitStrength and UCI_Elo? Because if it is true, then it might be beneficial to file a separate issue to focus on that in training data because a human can mate at move depth 1 or at least move depth 2 (not to be confused with engine depth or plies searched) in KRvK and therefore the best engine should as well. I would have expected training data that included tablebases that only rewarded shortest distance-to-mate to settle on that kind of behavior.

[ulthiel]

Why keep UCI_Elo at all? As you said as well, I think it is very difficult to implement an engine that plays like a human at a certain level. If it is that random and misunderstood, I wouldn't bother. (However, I think this would be an interesting task after succeeding to produce the chess engine that can beat everything).

The way we mimic strength is to pick a random move according to a distribution which over many games on average performs the same as an engine at that strength.

What is "an engine at that stength"?

[dav1312]

What is "an engine at that stength"?

An engine that plays at that strength. Maia 1500 for example, is an engine that plays at 1500 Lichess strength.
You can mimic Maia's 1500 strength by playing like a 1500 rated player, or by playing like Stockfish but make random one move blunders to lose the same amount of games you win.

[vondele]

This is related to the low depth used in the skill level, at this point not much that can be done.
Probably would need a substantial overhaul of the of the skill approach.

[vondele]

It actually could be that #6742 is related to this issue. I tried to test this issue with the likely fix of the other issue, and at least it mates (albeit not with the shortest mate).