Stockfish Development Versions are build automatically if there are changes on the master branch in the git repository (https://github.com/official-stockfish/Stockfish). Use it at your own risk.
They are compiled with gcc 11.2/mingw 10 on Ubuntu 22.04.

!! latest version !!


Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: sscg13
Date: Wed Feb 18 21:46:57 2026 +0100
Timestamp: 1771447617

Update NNUE architecture to SFNNv13 and net nn-5227780996d3.nnue

Since the introduction of Threat Inputs in SFNNv10 and its refinements, the
accumulator/L1 size has significantly decreased. This has made it more
computationally favorable to double the L2 size from 16 to 32.

Failed STC:
LLR: -2.98 (-2.94,2.94) <0.00,2.00>
Total: 189184 W: 49649 L: 49635 D: 89900 Elo +0.03
Ptnml(0-2): 881, 22479, 47812, 22585, 835
https://tests.stockfishchess.org/tests/view/69928ef7bfe62dc95a624d5c

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 37902 W: 9833 L: 9509 D: 18560 Elo +2.97
Ptnml(0-2): 35, 4074, 10408, 4400, 34
https://tests.stockfishchess.org/tests/view/69937936ff782f8eeef611e3

Passed VLTC SMP:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 20576 W: 5455 L: 5191 D: 9930 Elo +4.46
Ptnml(0-2): 6, 1837, 6338, 2101, 6
https://tests.stockfishchess.org/tests/view/6994df0586e4a32314116399

closes https://github.com/official-stockfish/Stockfish/pull/6619

bench: 2396996
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: mstembera
Date: Wed Feb 18 21:44:20 2026 +0100
Timestamp: 1771447460

Minor cleanups in bitboard.h

closes https://github.com/official-stockfish/Stockfish/pull/6618

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: mstembera
Date: Wed Feb 18 21:40:01 2026 +0100
Timestamp: 1771447201

Don't process kings after #6609

https://github.com/official-stockfish/Stockfish/pull/6617

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: rn5f107s2
Date: Wed Feb 18 21:39:06 2026 +0100
Timestamp: 1771447146

Add en passant santization tests to the CI and pos is ok

closes https://github.com/official-stockfish/Stockfish/pull/6615

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Carlos Esparza
Date: Wed Feb 18 05:58:44 2026 +0100
Timestamp: 1771390724

speed up update_piece_threats after SFNNv12

with the removal of all king-related threats in SFNNv12 we can avoid some work in update_piece_threats

STC for anematode's swan:
https://tests.stockfishchess.org/tests/view/6986b920b0f3ca5200aaf80a
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 262880 W: 68379 L: 67747 D: 126754 Elo +0.84
Ptnml(0-2): 808, 29001, 71223, 29567, 841

STC of further speedups on top of swan:
https://tests.stockfishchess.org/tests/view/698d7f8362a8f472da3a8a35
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 65920 W: 17126 L: 16781 D: 32013 Elo +1.82
Ptnml(0-2): 186, 7084, 18105, 7369, 216

closes https://github.com/official-stockfish/Stockfish/pull/6614

No functional change

Co-Authored-By: Timothy Herchen <>
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Wed Feb 18 05:54:55 2026 +0100
Timestamp: 1771390495

VVLTC tune

Passed VVLTC with stc bounds:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 21424 W: 5638 L: 5387 D: 10399 Elo +4.07
Ptnml(0-2): 2, 1925, 6607, 2176, 2
https://tests.stockfishchess.org/tests/view/69938fbcff782f8eeef612a9

Passed VVLTC with ltc bounds:
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 33410 W: 8784 L: 8499 D: 16127 Elo +2.96
Ptnml(0-2): 5, 2968, 10474, 3253, 5
https://tests.stockfishchess.org/tests/view/69923ea872254723ef22c6fa

Verify Elo loss at STC:
LLR: -2.93 (-2.94,2.94) <-1.75,0.25>
Total: 17504 W: 4420 L: 4704 D: 8380 Elo -5.64
Ptnml(0-2): 56, 2259, 4420, 1947, 70
https://tests.stockfishchess.org/tests/view/69946e4186e4a3231411625b

closes https://github.com/official-stockfish/Stockfish/pull/6616

bench: 3074962
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Daniel Monroe
Date: Fri Feb 13 07:22:36 2026 +0100
Timestamp: 1770963756

Simplify probCutDepth term

Passed STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 139392 W: 36003 L: 35897 D: 67492 Elo +0.26
Ptnml(0-2): 451, 16383, 35911, 16511, 440
https://tests.stockfishchess.org/tests/view/697ebb4d5f56030af97b5aa5

Passed LTC
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 266934 W: 67822 L: 67851 D: 131261 Elo -0.04
Ptnml(0-2): 175, 29579, 73955, 29616, 142
https://tests.stockfishchess.org/tests/view/6980e5a26362aee5c8a55398

closes https://github.com/official-stockfish/Stockfish/pull/6607

Bench: 2515956
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Daniel Monroe
Date: Fri Feb 13 07:15:35 2026 +0100
Timestamp: 1770963335

Simplify malus formula

Passed non-regression STC
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 51936 W: 13490 L: 13283 D: 25163 Elo +1.38
Ptnml(0-2): 161, 6128, 13184, 6333, 162
https://tests.stockfishchess.org/tests/view/698120e06362aee5c8a55412

Passed non-regression LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 233772 W: 59502 L: 59499 D: 114771 Elo +0.00
Ptnml(0-2): 144, 25753, 65086, 25762, 141
https://tests.stockfishchess.org/tests/view/69827426889c3a4c31c8db52

closes https://github.com/official-stockfish/Stockfish/pull/6606

bench 2739355
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Daniel Monroe
Date: Fri Feb 13 07:12:04 2026 +0100
Timestamp: 1770963124

Simplify malus decay formula

Passed non-regression STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 93600 W: 24165 L: 24007 D: 45428 Elo +0.59
Ptnml(0-2): 325, 11021, 23958, 11163, 333
https://tests.stockfishchess.org/tests/view/698121d46362aee5c8a55414

Passed non-regression LTC
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 83232 W: 21236 L: 21077 D: 40919 Elo +0.66
Ptnml(0-2): 46, 9147, 23083, 9282, 58
https://tests.stockfishchess.org/tests/view/698336dc473df9d1d24a90e8

closes https://github.com/official-stockfish/Stockfish/pull/6600

Bench: 2666284
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: anematode
Date: Fri Feb 13 07:06:33 2026 +0100
Timestamp: 1770962793

avoid modify_and_replicate for first load

We call modify_and_replicate in load_networks, but this is quite inefficient.

closes https://github.com/official-stockfish/Stockfish/pull/6574

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: lemteay
Date: Fri Feb 13 07:03:17 2026 +0100
Timestamp: 1770962597

Add constexpr specifier back to conthist_bonuses

Passed STC
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 60288 W: 15668 L: 15331 D: 29289 Elo +1.94
Ptnml(0-2): 159, 6490, 16532, 6781, 182
https://tests.stockfishchess.org/tests/view/698c835762a8f472da3a88e1

closes https://github.com/official-stockfish/Stockfish/pull/6611

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Maxim Masiutin
Date: Fri Feb 13 07:01:15 2026 +0100
Timestamp: 1770962475

Prefetch threat weight rows during append_changed_indices

Passed STC (first run):
https://tests.stockfishchess.org/tests/view/698030ee6362aee5c8a552c7
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 120800 W: 31336 L: 30912 D: 58552 Elo +1.22
Ptnml(0-2): 330, 13084, 33172, 13460, 354

Passed LTC:
https://tests.stockfishchess.org/tests/view/6983946d473df9d1d24a916d
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 86850 W: 22352 L: 21951 D: 42547 Elo +1.60
Ptnml(0-2): 45, 8506, 25934, 8883, 57

Passed STC SMP (after changes made after opening the PR):
https://tests.stockfishchess.org/tests/view/6987b4c1b0f3ca5200aaf9da
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 84480 W: 21994 L: 21627 D: 40859 Elo +1.51
Ptnml(0-2): 98, 9378, 22932, 9723, 109

Passed STC (second run, as a sanity check made after changes made after opening the PR -- these changed, however, didn't change assembly code produced by the compiler):
https://tests.stockfishchess.org/tests/view/6987ad21b0f3ca5200aaf9c9
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 132192 W: 34526 L: 34083 D: 63583 Elo +1.16
Ptnml(0-2): 421, 14511, 35759, 15014, 391

GCC maps __builtin_prefetch locality=1 to PREFETCHT2 instruction, targeting L2
cache. To make things clear, added template-based approach as suggested by
Disservin.

PREFETCHT2 should be the appropriate choice for the 78 MB threat weight table:
avoids L1d pollution, parks data in L2 where it is promoted to L1d on actual
load.

With 200-500 cycle lead time from make_index, data has time to arrive in L2.

suggestions by Disservin and anematode included

closes https://github.com/official-stockfish/Stockfish/pull/6602

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Joost VandeVondele
Date: Fri Feb 13 06:57:08 2026 +0100
Timestamp: 1770962228

Introduce timeout for wget/curl in net download

ensures the download terminates after 5min, even if the server stalled.

closes https://github.com/official-stockfish/Stockfish/pull/6608

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: sscg13
Date: Fri Feb 13 06:56:10 2026 +0100
Timestamp: 1770962170

Update NNUE architecture to SFNNv12 and net nn-7e1657811c6d.nnue

This net is trained with https://github.com/sscg13/nettest/blob/no-king-attacker/threats.yaml.

Passed non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 92640 W: 24371 L: 24209 D: 44060 Elo +0.61
Ptnml(0-2): 389, 11047, 23322, 11137, 425
https://tests.stockfishchess.org/tests/view/6986345fa259e26d2c32e9c5

Passed non-regression LTC:
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 198636 W: 50960 L: 50919 D: 96757 Elo +0.07
Ptnml(0-2): 176, 22218, 54511, 22215, 198
https://tests.stockfishchess.org/tests/view/6987ee29b0f3ca5200aafa51

closes https://github.com/official-stockfish/Stockfish/pull/6609

bench: 2465828
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Daniel Monroe
Date: Sun Feb 8 15:22:29 2026 +0100
Timestamp: 1770560549

Simplify away main history default

Passed non-regression STC
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 130752 W: 33725 L: 33605 D: 63422 Elo +0.32
Ptnml(0-2): 421, 15472, 33460, 15612, 411
https://tests.stockfishchess.org/tests/view/697eb9e35f56030af97b5a9e

Passed non-regression LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 53352 W: 13697 L: 13509 D: 26146 Elo +1.22
Ptnml(0-2): 36, 5804, 14811, 5986, 39
https://tests.stockfishchess.org/tests/view/6980e5846362aee5c8a55396

closes https://github.com/official-stockfish/Stockfish/pull/6590

Bench: 2375860
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Dieter Dobbelaere
Date: Sun Feb 8 15:22:21 2026 +0100
Timestamp: 1770560541

Replace FNV-1a hash by faster and better MurmurHash64A.

Replace FNV-1a hash algorithm by public domain MurmurHash64A, by Austin
Appleby, which is faster and has better hash properties. This is also
the default hash algorithm of GNU C++ Standard Library.

Startup time on a given system (with x86-64-avx2 binaries) reduces from
378ms to 332ms (46ms faster). Hashing of the largest data input (46.1MB)
goes from 44.2ms to 6.2ms, so about 7x faster.

No functional change

closes https://github.com/official-stockfish/Stockfish/pull/6579

Bench: 2570943
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: lemteay
Date: Sun Feb 8 15:22:06 2026 +0100
Timestamp: 1770560526

Raise inline threshold for clang/llvm

Passed STC:
https://tests.stockfishchess.org/tests/view/696884a56d118e46e1731473
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 29952 W: 7843 L: 7549 D: 14560 Elo +3.41
Ptnml(0-2): 72, 3215, 8118, 3489, 82

.text area size:
```
master(eb5a65a): 455490
pr: 453250
```

Bench (clang 21.1.8):
```
Result of 100 runs
==================
base (...kfish-master) = 1719708 +/- 3473
test (./stockfish ) = 1770555 +/- 3284
diff = +50846 +/- 3949

speedup = +0.0296
P(speedup > 0) = 1.0000

CPU: 16 x AMD Ryzen 9 7945HX with Radeon Graphics
Hyperthreading: on
```

closes https://github.com/official-stockfish/Stockfish/pull/6550

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Sun Feb 8 15:22:06 2026 +0100
Timestamp: 1770560526

Simplify Triple Margin Formula

Passed STC:
LLR: 3.01 (-2.94,2.94) <-1.75,0.25>
Total: 517472 W: 133271 L: 133575 D: 250626 Elo -0.20
Ptnml(0-2): 1628, 61366, 133032, 61102, 1608
https://tests.stockfishchess.org/tests/view/69590175d844c1ce7cc7e9a2

Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 95430 W: 24242 L: 24098 D: 47090 Elo +0.52
Ptnml(0-2): 42, 10289, 26926, 10399, 59
https://tests.stockfishchess.org/tests/view/695f7f03ca95f52e4b85253c

Passed VVLTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 58828 W: 15299 L: 15135 D: 28394 Elo +0.97
Ptnml(0-2): 4, 5277, 18687, 5443, 3
https://tests.stockfishchess.org/tests/view/6961686c8709a8d27c0383f6

closes https://github.com/official-stockfish/Stockfish/pull/6546

Bench: 2570943
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Jakub Ciolek
Date: Sun Feb 8 15:22:06 2026 +0100
Timestamp: 1770560526

Remove prefetching in Position::do_null_move

Passed non-regression STC, Hash=16:

LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 60704 W: 15709 L: 15522 D: 29473 Elo +1.07
Ptnml(0-2): 169, 6589, 16649, 6776, 169
https://tests.stockfishchess.org/tests/view/6963d381f6d2e8deff76918f

Passed non-regression STC SMP, Hash=512:

LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 313512 W: 80151 L: 80231 D: 153130 Elo -0.09
Ptnml(0-2): 376, 35492, 85111, 35390, 387
https://tests.stockfishchess.org/tests/view/696e1684e5a70879bd3fe38f

closes https://github.com/official-stockfish/Stockfish/pull/6545

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: ppigazzini
Date: Sun Feb 8 15:22:06 2026 +0100
Timestamp: 1770560526

feat(build): use lld for clang if available

Also simplify the CI.

closes https://github.com/official-stockfish/Stockfish/pull/6592

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: mstembera
Date: Sun Feb 8 15:22:06 2026 +0100
Timestamp: 1770560526

Minor fixes for MSVC

closes https://github.com/official-stockfish/Stockfish/pull/6596

No functional change
see source
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Disservin
Date: Sun Feb 8 15:20:42 2026 +0100
Timestamp: 1770560442

Fix Strict Aliasing Violation

Even though this failed with non regression bounds on fishtest, merging
it as is to improve the current situation.

Failed Non Regression:
https://tests.stockfishchess.org/tests/view/6988814db0f3ca5200aafb50
LLR: -2.94 (-2.94,2.94) <-1.75,0.25>
Total: 185792 W: 48109 L: 48565 D: 89118 Elo -0.85
Ptnml(0-2): 553, 21228, 49811, 20730, 574

Previously we had code similar to this
```
alignas(64) std::uint8_t foo[1024];
const auto* int_ptr = reinterpret_cast<const std::int32_t*>(foo);
```

Which is a strict aliasing violation once we dereference int_ptr, which
invokes UB and causes newer gcc version to emit incorrect code.

fixes https://github.com/official-stockfish/Stockfish/issues/6598
fixes https://github.com/official-stockfish/Stockfish/issues/4932

This violation was introduced in PR #3287 and merged in commit 23c385e.
Due to aggressive compiler optimizations, users may need to include
CXXFLAGS=-fno-strict-aliasing as a build argument to ensure a correctly
functioning binary.

Also thanks to @anematode for writing parts of this and realizing this
strict aliasing violation.

closes https://github.com/official-stockfish/Stockfish/pull/6599

Bench: 2668754

Co-Authored-By: Timothy Herchen <>
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: sscg13
Date: Wed Feb 4 18:26:28 2026 +0100
Timestamp: 1770225988

Update NNUE architecture to SFNNv11 and net nn-3dd094f3dfcf.nnue

Removes threat features of the form piece -> king, thus saving 13MB of net
space and approximately 0.8 threat feature updates per incremental accumulator
update.

Passed non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 33664 W: 8864 L: 8636 D: 16164 Elo +2.35
Ptnml(0-2): 136, 3926, 8501, 4112, 157
https://tests.stockfishchess.org/tests/view/6981dcda4776a4e6e7fef2ac

Passed non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 46896 W: 12077 L: 11881 D: 22938 Elo +1.45
Ptnml(0-2): 41, 5118, 12924, 5334, 31
https://tests.stockfishchess.org/tests/view/69827c6beb87369ff4d0c7d5

closes https://github.com/official-stockfish/Stockfish/pull/6593

bench: 2668754
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Pieter te Brake
Date: Wed Feb 4 18:22:07 2026 +0100
Timestamp: 1770225727

Update castling rights unconditionally.

passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 163680 W: 42214 L: 42137 D: 79329 Elo +0.16
Ptnml(0-2): 454, 18054, 44734, 18157, 441
https://tests.stockfishchess.org/tests/view/697e6f4e5f56030af97b5a3c

closes https://github.com/official-stockfish/Stockfish/pull/6588

No functional change
see source
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Pieter te Brake
Date: Wed Feb 4 18:17:23 2026 +0100
Timestamp: 1770225443

Simplify en passant square update in Position::do_move().

Passed non-regression STC:

LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 119680 W: 31011 L: 30884 D: 57785 Elo +0.37
Ptnml(0-2): 354, 13231, 32575, 13294, 386
https://tests.stockfishchess.org/tests/view/6973b06c6cd60a8e97ca62e5

closes https://github.com/official-stockfish/Stockfish/pull/6565

No functional change
see source

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