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: 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
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: KazApps
Date: Wed Feb 4 18:09:00 2026 +0100
Timestamp: 1770224940

refactor update_piece_threats to reduce branching

Passed STC Non-Regression:
https://tests.stockfishchess.org/tests/view/696f1a398b64097dacd231c3
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 122272 W: 31587 L: 31466 D: 59219 Elo +0.34
Ptnml(0-2): 301, 13358, 33750, 13373, 354

slight speedup as well:

1 thread bench:
sf_base = 2238429 +/- 1221 (95%)
sf_test = 2248298 +/- 1371 (95%)
diff = 9869 +/- 1571 (95%)
speedup = 0.44090% +/- 0.070% (95%)

32 thread speedtest:
sf_base = 41016996 +/- 83654 (95%)
sf_test = 41185801 +/- 84269 (95%)
diff = 168805 +/- 79986 (95%)
speedup = 0.41155% +/- 0.195% (95%)

closes https://github.com/official-stockfish/Stockfish/pull/6559

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: disservin
Date: Wed Feb 4 18:00:54 2026 +0100
Timestamp: 1770224454

Don't push prerelease for release commits

Looks for the text "Official release version of Stockfish" in the commit
message to determine if something is a release.

closes https://github.com/official-stockfish/Stockfish/pull/6580

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: ppigazzini
Date: Wed Feb 4 17:58:55 2026 +0100
Timestamp: 1770224335

refactor(scripts): improve `get_native_properties.sh`

Improve `get_native_properties.sh` with a refreshed implementation.
The new version covers all Makefile ARCH variants and keeps the
script interface stable while improving portability and CPU feature
detection across supported platforms. Drop the asset file name to
avoid coupling outputs to a specific artifact naming scheme.

Refs: https://github.com/ppigazzini/get-native-properties (includes a
testing framework)

closes https://github.com/official-stockfish/Stockfish/pull/6552

No functional change.
see source
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 4 17:56:00 2026 +0100
Timestamp: 1770224160

Only record the ep square from a given FEN if ep is legal

When given a FEN with an ep square set, only actually set the ep square if there is a legal ep capture that can be played.

Fixes #6563

closes https://github.com/official-stockfish/Stockfish/pull/6564

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: disservin
Date: Wed Feb 4 17:46:47 2026 +0100
Timestamp: 1770223607

Improve usage of sf_assume

Make the sf_assume also have an effect with clang and help the compiler
proof it's side effect free by comparing against a variable.

https://tests.stockfishchess.org/tests/view/6979d14fa2c75f923be1e681
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 63488 W: 16530 L: 16188 D: 30770 Elo +1.87
Ptnml(0-2): 167, 6904, 17277, 7212, 184

closes https://github.com/official-stockfish/Stockfish/pull/6573

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: Maxim Masiutin
Date: Wed Feb 4 17:44:25 2026 +0100
Timestamp: 1770223465

Branchless correction history with to_sq_unchecked

Add Move::to_sq_unchecked() that bypasses the is_ok() assertion,
for use in branchless code paths where invalid moves are masked out.

passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 92384 W: 24052 L: 23665 D: 44667 Elo +1.46
Ptnml(0-2): 265, 10229, 24831, 10588, 279
https://tests.stockfishchess.org/tests/view/6974dfc798dc5fff1dba5b74

closes https://github.com/official-stockfish/Stockfish/pull/6569

No functional change
see source

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