Dev Builds » 20260409-1956

Use this dev build

NCM plays each Stockfish dev build 20,000 times against Stockfish 15. This yields an approximate Elo difference and establishes confidence in the strength of the dev builds.

Summary

Host Duration Avg Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo
ncm-dbt-01 06:45:22 581908 3998 1737 353 1908 +125.45 ± 4.56 0 37 569 1365 28 +286.99 ± 14.27
ncm-dbt-02 06:43:45 584885 4000 1736 369 1895 +123.71 ± 4.56 0 41 573 1364 22 +283.26 ± 14.23
ncm-dbt-03 06:44:27 583895 4000 1750 352 1898 +126.77 ± 4.46 0 24 584 1362 30 +290.66 ± 14.04
ncm-dbt-04 06:44:42 567751 4006 1753 344 1909 +127.65 ± 4.66 1 31 575 1350 46 +288.7 ± 14.18
ncm-dbt-05 06:45:37 581538 3996 1759 370 1867 +126.02 ± 4.49 0 34 564 1377 23 +290.46 ± 14.33
20000 8735 1788 9477 +125.92 ± 2.03 1 167 2865 6818 149 +288.0 ± 6.35

Test Detail

ID Host Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo CLI PGN
463524 ncm-dbt-04 567680 6 3 0 3 +190.46 ± 18.51 0 0 0 3 0 +1199.83 ± 276.48
463523 ncm-dbt-05 583740 496 217 54 225 +118.57 ± 13.06 0 6 75 165 2 +268.88 ± 39.66
463522 ncm-dbt-01 583321 498 206 52 240 +111.07 ± 13.26 0 5 89 151 4 +242.14 ± 36.09
463521 ncm-dbt-03 581610 500 222 49 229 +125.38 ± 12.7 0 3 75 168 4 +285.49 ± 39.5
463520 ncm-dbt-02 586181 500 220 49 231 +123.81 ± 13.81 0 9 65 172 4 +280.42 ± 42.65
463519 ncm-dbt-04 567363 500 223 44 233 +130.14 ± 14.9 0 5 76 154 15 +273.0 ± 39.35
463518 ncm-dbt-05 585084 500 214 37 249 +128.55 ± 13.01 0 5 67 174 4 +295.94 ± 42.08
463517 ncm-dbt-03 583154 500 210 45 245 +119.11 ± 12.43 0 2 84 161 3 +268.17 ± 36.99
463516 ncm-dbt-01 583196 500 216 39 245 +128.55 ± 12.43 0 3 70 174 3 +298.62 ± 41.01
463515 ncm-dbt-02 583740 500 226 39 235 +136.56 ± 11.97 0 2 62 183 3 +327.18 ± 43.69
463514 ncm-dbt-04 568156 500 213 41 246 +124.6 ± 13.45 0 7 68 171 4 +282.94 ± 41.76
463513 ncm-dbt-05 581943 500 219 45 236 +126.17 ± 12.49 0 4 70 174 2 +293.29 ± 41.07
463512 ncm-dbt-03 586266 500 208 30 262 +129.35 ± 11.81 0 2 69 178 1 +306.84 ± 41.23
463511 ncm-dbt-01 582945 500 217 55 228 +116.77 ± 13.36 0 8 74 166 2 +263.42 ± 39.97
463510 ncm-dbt-02 586223 500 217 51 232 +119.89 ± 12.42 0 4 77 168 1 +275.45 ± 39.01
463509 ncm-dbt-04 567918 500 215 43 242 +124.6 ± 12.71 0 4 73 170 3 +285.49 ± 40.16
463508 ncm-dbt-05 582235 500 233 38 229 +143.07 ± 11.91 0 3 52 192 3 +352.8 ± 48.05
463507 ncm-dbt-03 587155 500 227 47 226 +130.94 ± 13.69 0 5 68 169 8 +293.29 ± 41.75
463506 ncm-dbt-01 580282 500 216 41 243 +126.97 ± 12.85 0 7 62 180 1 +298.62 ± 43.77
463505 ncm-dbt-04 567205 500 226 43 231 +133.34 ± 13.08 0 2 71 169 8 +301.33 ± 40.6
463504 ncm-dbt-02 585126 500 215 47 238 +121.45 ± 12.58 0 4 76 168 2 +277.93 ± 39.29
463503 ncm-dbt-05 579744 500 231 48 221 +133.34 ± 12.09 0 2 66 179 3 +315.35 ± 42.24
463502 ncm-dbt-04 567284 500 221 40 239 +131.74 ± 12.34 0 3 66 178 3 +309.64 ± 42.33
463501 ncm-dbt-03 584369 500 218 46 236 +124.6 ± 12.71 0 4 73 170 3 +285.49 ± 40.16
463500 ncm-dbt-01 580904 500 217 40 243 +128.55 ± 12.04 0 3 68 178 1 +304.07 ± 41.65
463499 ncm-dbt-02 585000 500 216 49 235 +120.67 ± 13.5 0 6 76 163 5 +268.17 ± 39.39
463498 ncm-dbt-05 579042 500 215 56 229 +114.45 ± 13.38 0 7 80 160 3 +254.16 ± 38.36
463497 ncm-dbt-04 567165 500 213 50 237 +117.55 ± 13.87 1 5 79 160 5 +261.07 ± 38.58
463496 ncm-dbt-01 581277 500 215 41 244 +126.17 ± 12.3 0 2 75 170 3 +290.66 ± 39.4
463495 ncm-dbt-03 584622 500 225 39 236 +135.76 ± 12.01 0 1 66 179 4 +321.19 ± 42.12
463494 ncm-dbt-02 585126 500 223 46 231 +128.55 ± 12.43 0 3 70 174 3 +298.62 ± 41.01
463493 ncm-dbt-05 580365 500 214 49 237 +119.11 ± 12.8 0 5 77 166 2 +270.57 ± 39.07
463492 ncm-dbt-04 568196 500 219 40 241 +130.14 ± 12.78 0 3 70 172 5 +298.62 ± 41.01
463491 ncm-dbt-01 581028 500 221 41 238 +130.94 ± 14.39 0 7 66 167 10 +288.06 ± 42.4
463490 ncm-dbt-02 583447 500 210 47 243 +117.55 ± 13.0 0 5 80 162 3 +263.42 ± 38.27
463489 ncm-dbt-03 579496 500 216 42 242 +126.17 ± 12.49 0 3 73 171 3 +290.66 ± 40.08
463488 ncm-dbt-05 580157 500 216 43 241 +125.38 ± 12.51 0 2 77 167 4 +285.49 ± 38.83
463487 ncm-dbt-04 568792 500 220 43 237 +128.55 ± 12.24 0 2 72 173 3 +298.62 ± 40.29
463486 ncm-dbt-01 582318 500 229 44 227 +134.95 ± 12.24 0 2 65 179 4 +318.25 ± 42.59
463485 ncm-dbt-02 584243 500 209 41 250 +121.45 ± 13.14 0 8 67 174 1 +280.42 ± 42.05
463484 ncm-dbt-03 584495 500 224 54 222 +123.02 ± 12.93 0 4 76 166 4 +277.93 ± 39.29

Commit

Commit ID d3a4587fe881a531d08b17d45d9c12ded9680ee4
Author Robert Nurnberg @ elitebook
Date 2026-04-09 19:56:05 UTC
Simplify uci pv output logic The uci pv suppression and PV roll-back logic in master is a bit convoluted, which makes it hard to reason about the code. In fact, subtle bugs that led to wrong mated-in scores in game play or a mismatch between bestmove and first PV move were only recently fixed. Moreover, in master the uci pv output through `pv()` is called in four different places. This PR proposes to simplify this logic. In this patch, the PV is sent to the GUI from within `iterative_deepening()` only (a) for fail highs/lows or (b) when an iteration for a root move is completed. All other PV outputs are now handled by `start_searching()`, just before the bestmove extraction. This easily ensures that bestmove (and ponder move) will always be in sync with the final PV output. The only noticeable change to master is for multi-threaded searches that do not involve `limits.depth`. Here master would show both the PV from the aborted search in main thread, as well as the new PV from the selected best thread. This patch would only show the latter. While at it, we also remove the requirement to finish at least a depth 1 search and simplify the logic around stalemates/checkmates at root and in particular avoid any PVs that start with `Move::none()`. Passed STC non-reg: LLR: 2.96 (-2.94,2.94) <-1.75,0.25> Total: 72416 W: 18784 L: 18609 D: 35023 Ptnml(0-2): 200, 7762, 20127, 7901, 218 https://tests.stockfishchess.org/tests/view/69d3ef0c33584dad27b3c85a closes https://github.com/official-stockfish/Stockfish/pull/6704 No functional change
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