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.

This server will shut down on March 30th. You can download development versions of Stockfish here https://github.com/official-stockfish/Stockfish/releases



!! 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: anematode
Date: Wed Mar 18 20:49:20 2026 +0100
Timestamp: 1773863360

Speedup splat_moves on avx512icl

STC
```
LLR: 5.45 (-2.94,2.94) <0.00,2.00>
Total: 612192 W: 158602 L: 157260 D: 296330 Elo +0.76
Ptnml(0-2): 1634, 67783, 166027, 68911, 1741
```

@Torom measured:
```
sf_base = 2380902 +/- 1016 (95%)
sf_test = 2391426 +/- 1065 (95%)
diff = 10524 +/- 1336 (95%)
speedup = 0.44203% +/- 0.056% (95%)
```

I've verified that `_mm512_slli_epi16(v, 0)` gets optimized out in GCC
9+ and clang 4+. Added constants to types.h so that people messing
around with the layout of `Move` don't have to know about this part of
the code.

closes https://github.com/official-stockfish/Stockfish/pull/6670

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: Wed Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

VVLTC Tune

Passed VVLTC with stc bounds:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 69810 W: 18119 L: 17814 D: 33877 Elo +1.52
Ptnml(0-2): 6, 6222, 22144, 6527, 6
https://tests.stockfishchess.org/tests/view/69b43f666c456d3a77a50a5d

Passed VVLTC with ltc bounds:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 52458 W: 13574 L: 13258 D: 25626 Elo +2.09
Ptnml(0-2): 5, 4632, 16636, 4954, 2
https://tests.stockfishchess.org/tests/view/69b16dfbd0c9228834e88e99

closes https://github.com/official-stockfish/Stockfish/pull/6669

Bench: 3164843
see source
Windows x64 for Haswell CPUs
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: Robert Nurnberg @ elitebook
Date: Wed Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

Improve multi-threaded go-mate searches

Ever since #5094 master only lets the main thread terminate `go mate`
searches, reverting the earlier improvement #1215.

This PR restores the old logic. So any thread that found a "mate in x"
can now stop the search.

To make this work robustly, we need to guard against inexact mate scores
in the best thread selection. In addition, in contrast to time limits,
the main thread may now not complete a d1 search for a mated-in
position.
In master an aborted d1 search may have a PV beginning with
`Move::none()`, in which case no thread selection is performed. See
#623. We fix this bug here by checking if `lastBestPV` is empty or not.
For interrupted d1 searches we now label mated-in scores as inexact.

While at it, we also simplify the logic for detecting if we can
terminate a go mate x search, using the fact that threads.stop can only
be false if we have a completed iteration with a valid score.

The PR has no effect on game play, but should slightly improve general
mate finding and speed up multi-threaded `go mate` searches.

We also add a corresponding matecheck run to the CI. This only involves
61 mates up to mate-in-2. Test runs with the first 50 or 100 mates from
`mates2000.epd` did at times not finish within 30 minutes on my fork or
in local tests, possibly due to search explosions for some mate-in-3
positions.

closes https://github.com/official-stockfish/Stockfish/pull/6668

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: Pieter te Brake
Date: Wed Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

Use existing function for removing and placing a piece.

Passed non-regression STC:
```
LLR: 3.33 (-2.94,2.94) <-1.75,0.25>
Total: 359712 W: 93077 L: 93175 D: 173460 Elo -0.09
Ptnml(0-2): 1088, 39816, 98144, 39722, 1086
```
https://tests.stockfishchess.org/tests/view/69af5e9a6b61ccc788710e31

closes https://github.com/official-stockfish/Stockfish/pull/6667

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: Tomasz Sobczyk
Date: Wed Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

Strict FEN parsing. Exit on setting invalid position via UCI.

fixes #6663, #6664, and a million others issues raised over the years.

This is similar to
https://github.com/official-stockfish/Stockfish/pull/4563/changes but
more conservative and errors are split between "Unsupported position"
and "Invalid FEN".

The FEN parser needs to be strict as a foundation for safety. It does
not specify much of the semantics, so this step is fairly simple. Parts
after the ep square are optional, however, since it's common, for
example in EPD notation.

Errors arising from positional semantics that were previously bucketed
under invalid FENs are now reported as "Unsupported position". Only
positions that are potentially problematic are designated as
unsupported. It is NOT guided by illegality of the position, but instead
by the ability of the engine to handle them correctly. This means that
some checks from the previous PR were removed.

std::exit is used instead of std::terminate so atexit handles will be
called.

Probably wise to run copilot on this or smth because I scribbled it
without much thought.

With these small changes and reduced, less controversial, scope I hope
this PR will finally make it and we will be done with these weekly
issues. I'll wait with putting it on fishtest until there's approval.

closes https://github.com/official-stockfish/Stockfish/pull/6665

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 Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

Don't recompile misc.cpp on every run

alternative to https://github.com/official-stockfish/Stockfish/pull/6660

closes https://github.com/official-stockfish/Stockfish/pull/6662

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: MARLIN-Tools
Date: Wed Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

Fix Depth 1 bug at very low time controls, some fishtesting workers, and delayed move senders like Arena.

Non-Regression STC:

LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 98208 W: 25423 L: 25276 D: 47509 Elo +0.52
Ptnml(0-2): 271, 10713, 26994, 10850, 276
https://tests.stockfishchess.org/tests/view/69ad43c21d849c824c6afe82

-

Hell VVSTC (0.2+0.02)
LLR: 2.70 (-2.94,2.94) <0.00,2.00>
Total: 688 W: 660 L: 11 D: 17 Elo +614.03
Ptnml(0-2): 1, 0, 10, 15, 318
https://tests.stockfishchess.org/tests/view/69ae4bea1d849c824c6b00b0

-

Sudden Death (1+0)

LLR: 2.19 (-2.94,2.94) <-1.75,0.25>
Total: 538 W: 536 L: 0 D: 2 Elo +1091.99
Ptnml(0-2): 0, 0, 0, 2, 267
https://tests.stockfishchess.org/tests/live_elo/69ae6c031d849c824c6b00dc

-

Sudden Death (5+0)

LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 22248 W: 6058 L: 5802 D: 10388 Elo +4.00
Ptnml(0-2): 214, 2420, 5583, 2710, 197
https://tests.stockfishchess.org/tests/view/69ae6dd01d849c824c6b00ee

-

Fixes #6639

closes https://github.com/official-stockfish/Stockfish/pull/6659

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Ryan Hirsch
Date: Wed Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

Speed up update_accumulator_refresh_cache with AVX512ICL

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 212960 W: 55550 L: 54991 D: 102419 Elo +0.91
Ptnml(0-2): 583, 23688, 57393, 24219, 597
https://tests.stockfishchess.org/tests/view/69ab916ccb31ee884aed62ea

closes https://github.com/official-stockfish/Stockfish/pull/6657

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: ZlomenyMesic
Date: Wed Mar 18 20:49:06 2026 +0100
Timestamp: 1773863346

Disable IIR and quiet shallow pruning in PV lines

Disable IIR and quiet shallow pruning in nodes that are part of the PV
line from the previous search iteration. This is done by storing the PV
in Worker and adding a followPV flag to Stack. The new flag may also be
used in other pruning techniques, allowing further improvement.

Passed STC:
```
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 63776 W: 16679 L: 16323 D: 30774 Elo +1.94
Ptnml(0-2): 169, 7441, 16377, 7667, 234
```
https://tests.stockfishchess.org/tests/view/69aad1a7d0f65de95886e289

Passed LTC:
```
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 87342 W: 22421 L: 22000 D: 42921 Elo +1.67
Ptnml(0-2): 40, 9443, 24299, 9834, 55
```
https://tests.stockfishchess.org/tests/view/69ab5993cb31ee884aed629d

closes https://github.com/official-stockfish/Stockfish/pull/6656

Bench: 2434614
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: Sat Mar 7 22:28:06 2026 +0100
Timestamp: 1772918886

Fix avx512icl update_piece_threats bug

Thanks to MinetaS for discovering this and finding the culprit commit,
specific to this architecture. 9f42980 was subtly incorrect, leading to
spurious wrong benches on avx512icl. Because this piece of code has twice been
the source of wrong benches, I also added a brief comment explaining why it
needs to be this way, and added a sample position to bench.

closes https://github.com/official-stockfish/Stockfish/pull/6654

Bench: 2288704
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: Shawn Xu
Date: Sat Mar 7 22:20:46 2026 +0100
Timestamp: 1772918446

Requantize smallnet to nn-47fc8b7fff06.nnue

Passed Non-regression STC:
LLR: 3.01 (-2.94,2.94) <-1.75,0.25>
Total: 340384 W: 88165 L: 88274 D: 163945 Elo -0.11
Ptnml(0-2): 1145, 40248, 87571, 40027, 1201
https://tests.stockfishchess.org/tests/view/69a4c49ab4a714eaaa196bc0

Passed Non-regression LTC:
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 125922 W: 32222 L: 32106 D: 61594 Elo +0.32
Ptnml(0-2): 100, 13815, 35002, 13957, 87
https://tests.stockfishchess.org/tests/view/69a9d5f489704e42c5e3a35d

closes https://github.com/official-stockfish/Stockfish/pull/6655

Bench: 2171643
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: Sat Mar 7 22:16:22 2026 +0100
Timestamp: 1772918182

Counter-Move History Continuity (CMHC)

Currently, the engine updates each level of the continuation history stack (ply -1, -2, -3, etc.) with fixed weights that are independent of one another. The idea behind CMHC is to scale the magnitude of these updates based on the consistency of the move's performance across the stack.
By tracking how often a move has historically performed well (positive history) within the current continuation context, we can adjust the update magnitude dynamically. Moves that demonstrate "continuity" (appearing as strong candidates across multiple historical contexts) receive more significant updates, while unproven or inconsistent moves are dampened.

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 103264 W: 26954 L: 26541 D: 49769 Elo +1.39
Ptnml(0-2): 338, 11910, 26728, 12313, 343
https://tests.stockfishchess.org/tests/view/69a81702fac54339cf435a87

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 47406 W: 12259 L: 11920 D: 23227 Elo +2.48
Ptnml(0-2): 22, 5052, 13237, 5349, 43
https://tests.stockfishchess.org/tests/view/69aab480bd35724e4b290498

closes https://github.com/official-stockfish/Stockfish/pull/6653

Bench: 2356418

Co-Authored-By: Daniel Samek <>
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: Shawn Xu
Date: Sat Mar 7 22:12:51 2026 +0100
Timestamp: 1772917971

Update main network to nn-9a0cc2a62c52.nnue

network with new hash encoding.

closes https://github.com/official-stockfish/Stockfish/pull/6651

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: Robert Nurnberg @ elitebook
Date: Sat Mar 7 22:10:14 2026 +0100
Timestamp: 1772917814

[CI] add multithreaded matetrack runs that simulate gameplay

closes https://github.com/official-stockfish/Stockfish/pull/6641

No functional change
see source
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: maximmasiutin
Date: Sat Feb 28 12:10:50 2026 +0100
Timestamp: 1772277050

Simplify attackers_to_exist function

test based on #6586 by maximmasiutin

https://tests.stockfishchess.org/tests/view/69977d58e2562aa5bc1e09c4
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 225056 W: 58208 L: 58195 D: 108653 Elo +0.02
Ptnml(0-2): 677, 25001, 61196, 24940, 714

closes https://github.com/official-stockfish/Stockfish/pull/6633

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: anematode
Date: Sat Feb 28 12:07:38 2026 +0100
Timestamp: 1772276858

skip setting threatByLesser[KING]

It doesn't make sense for a king to move to a square threatened by a lesser
piece, since that move would be illegal.

closes https://github.com/official-stockfish/Stockfish/pull/6640

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: Sat Feb 28 12:06:39 2026 +0100
Timestamp: 1772276799

Simplify threat by lesser

STC https://tests.stockfishchess.org/tests/view/699da988eaae015cd278ede4
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 141184 W: 36647 L: 36541 D: 67996 Elo +0.26
Ptnml(0-2): 511, 16620, 36237, 16700, 524

LTC https://tests.stockfishchess.org/tests/view/699f4bee2be03365d5073c71
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 99852 W: 25463 L: 25322 D: 49067 Elo +0.49
Ptnml(0-2): 47, 10997, 27721, 11090, 71

Removes a constant and a branch(for the price of a subtract) and treats the
from and to squares symmetrically.

closes https://github.com/official-stockfish/Stockfish/pull/6637

bench: 2460547
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: ByteBuf
Date: Sat Feb 28 12:00:08 2026 +0100
Timestamp: 1772276408

CI: Fix typo in error message

closes https://github.com/official-stockfish/Stockfish/pull/6624

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: Ryan Hirsch
Date: Sat Feb 28 11:58:49 2026 +0100
Timestamp: 1772276329

More NMP when improving

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 89472 W: 23291 L: 22895 D: 43286 Elo +1.54
Ptnml(0-2): 317, 10389, 22942, 10757, 331
https://tests.stockfishchess.org/tests/view/699f070c3ece4c464328a26f

Passed LTC:
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 95880 W: 24537 L: 24098 D: 47245 Elo +1.59
Ptnml(0-2): 55, 10259, 26880, 10684, 62
https://tests.stockfishchess.org/tests/view/699fb9be44b9136df1165ded

closes https://github.com/official-stockfish/Stockfish/pull/6638

bench: 2534375
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: Robert Nurnberg
Date: Sat Feb 28 11:55:03 2026 +0100
Timestamp: 1772276103

prevent unproven mated-in scores in game play

This PR removes the variable threads.abortedSearch introduced in #4990 and
relies on threads.stop and completedDepth instead.

The logic in master is only guaranteed to work in single threaded search. For
multiple threads, as soon as threads.stop is set, some of the threads may abort
their search, and so their mated-in scores are not reliable.

Compared to master, this patch prevents unproven mated-in scores in these
multi-threaded scenarios:

in game play (when time management is used)
when the uci commands quit or stop are received
when maximum depth is reached
for go mate commands

The patch will change the bestmove in those very rare situations where the bug
occurs in master. This is because bestmove is taken from rootMoves[0].pv[0],
which will now no longer contain unproven mated-in PVs. In that sense the patch
is "functional". But of course, it does not change bench.

While at it, we also fix a bug in master that suppressed PV output for inexact
mated-in scores on receiving threads.stop. In cases where uciScore < score with
score not being a proven loss, and where the new bestmove was different from
the last completed iteration, this led to a bestmove output that did not match
the final PV (which was for an exact score).

Fixes #6293.

Fixes #6626.

closes https://github.com/official-stockfish/Stockfish/pull/6636

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: 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

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