Category: Engine

Release Date: 2024-12-30
Language(s): C#
Repo Owner: Dragjon
Repo URL: https://github.com/Dragjon/Nectar

Score of NectarV0.2.2 vs NectarV0.2.1: 151 - 63 - 40  [0.673] 254
...      NectarV0.2.2 playing White: 74 - 28 - 25  [0.681] 127
...      NectarV0.2.2 playing Black: 77 - 35 - 15  [0.665] 127
...      White vs Black: 109 - 105 - 40  [0.508] 254
Elo difference: 125.6 +/- 41.5, LOS: 100.0 %, DrawRatio: 15.7 %
SPRT: llr 2.96 (100.7%), lbound -2.94, ubound 2.94 - H1 was accepted

https://github.com/Dragjon/Nectar/releases/download/V0.2.2/NectarV0.2.2-linux.zip
https://github.com/Dragjon/Nectar/releases/download/V0.2.2/NectarV0.2.2.zip
https://github.com/Dragjon/Nectar/archive/refs/tags/V0.2.2.zip

Author(s): Semih Özalp (AUT)
Release Date: 2024-12-28
Language(s): C++
Repo Owner: h1me01
Repo URL: https://github.com/h1me01/Astra

Release Notes

History Updates

  • Added 6-Ply Continuation History
  • Added Capture History
  • Added Correction Histories
  • Improved overall move history tracking and updating

Search Improvements

  • Removed Check Extension
  • Improved static evaluation
  • Added history pruning
  • Improved null move pruning
  • Improved singular extension
  • Improved late move pruning
  • Improved delta pruning in quiescence search

Miscellaneous

  • Introduced a new, more flexible move generation
  • More efficient move picker

https://github.com/h1me01/Astra/releases/download/4.1/astra-4.1-avx2.exe
https://github.com/h1me01/Astra/releases/download/4.1/astra-4.1-avx512.exe
https://github.com/h1me01/Astra/releases/download/4.1/nn-768-2×1024-1.nnue
https://github.com/h1me01/Astra/archive/refs/tags/4.1.zip

Author(s): Volodymyr Shcherbyna (UKR)
Release Date: 2024-12-28
Languages: C/C++
Repo Owner: vscherbyna
Repo URL: https://github.com/vshcherbyna/igel

What’s new:

  • extend by 2 in singular extension on non pv move
  • improve low bound condition in singular extension
  • check beta score in probcut condition
  • store in TT in standing pat in qsearch
  • implement iid
  • tune null move depth
  • tune razor depth
  • remove instant moves handling

Regression run against Igel 3.5.0:

Long Time Control With Increment (60s+0.6s)

Elo   | 21.28 +- 3.60 (95%)
Conf  | 60.0+0.60s Threads=1 Hash=64MB
Games | N: 8860 W: 2461 L: 1919 D: 4480
Penta | [7, 798, 2299, 1298, 28]

Short Time Control With Increment (10s+0.1s)

Elo   | 20.07 +- 3.21 (95%)
Conf  | 10.0+0.10s Threads=1 Hash=8MB
Games | N: 13918 W: 3953 L: 3150 D: 6815
Penta | [76, 1392, 3306, 2023, 162]

https://github.com/vshcherbyna/igel/releases/download/3.6.0/igel-x64_bmi2_avx2_3_6_0.exe
https://github.com/vshcherbyna/igel/releases/download/3.6.0/igel-x64_popcnt_avx2_3_6_0.exe
https://github.com/vshcherbyna/igel/archive/refs/tags/3.6.0.zip

Release Date: 2024-12-28
Language: C
Repo Owner: Jakob256
Repo URL: https://github.com/Jakob256/PurplePanda

Score against Version 18: 64% (+100 Elo)

  • moveordering refactored and considers “defended by a pawn” for own pieces
  • if depth2go>=4 and no hashmove is available, a shallow search is used to find the most promising move
  • beta-pruning at depth2go=1,2,3 with margins 0cp, 250cp and 500cp
  • 4 captures extend the search by 2 ply
  • repetition detection: if a position occures twice in the search tree, it is evaluated as drawn

https://github.com/Jakob256/PurplePanda/releases/download/v19/PurplePanda19.exe
https://github.com/Jakob256/PurplePanda/archive/refs/tags/v19.zip

Author(s): Rei Meguro (USA)
Release Date: 2024-12-27
Language: C++
Repo Owner: Orbital-Web
Repo URL: https://github.com/Orbital-Web/Raphael

  • Used GediminasMasaitis’s Texel Tuner to tune evaluation parameters
  • Switched to fully tapered evaluation (not just a select few parameters)
  • Added bishop-colored corner distance boost
  • Added bishop pair bonus
  • Added early draw evaluation evaluation scaling to avoid premature captures that result in draws

ELO Increase: 118

https://github.com/Orbital-Web/Raphael/releases/download/v1.8.0/Raphael1.8.0.0.exe
https://github.com/Orbital-Web/Raphael/archive/refs/tags/v1.8.0.zip

Author: Eduardo Cáceres
Release Date: 2024-12-20
Language: C#
Protocol: UCI
Repo Owner: lynx-chess
Repo URL: https://github.com/lynx-chess/Lynx

Full Changelog: v1.7.0…v1.8.0

https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-linux-arm.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-linux-arm64.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-linux-musl-x64.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-linux-x64.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-osx-arm64.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-osx-x64.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-win-arm64.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/Lynx-1.8.0-win-x64.zip
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/LynxChess.Lynx.1.8.0.nupkg
https://github.com/lynx-chess/Lynx/releases/download/v1.8.0/LynxChess.Lynx.1.8.0.snupkg
https://github.com/lynx-chess/Lynx/archive/refs/tags/v1.8.0.zip
https://github.com/lynx-chess/Lynx/archive/refs/tags/v1.8.0.tar.gz

Author(s): Norman Schmidt (BEL)
Release Date: 2024-12-17
Language: C++
Protocol: UCI
Repo Owner: FireFather
Repo URL: https://github.com/FireFather/ippolit

Here is source code for the original revolutionary & ground-breaking chess engine from 2009. Now ported to C++. Includes Visual studio project files… For clarity, the source code (which originally incorporated one single file)…has been re-organized to include logical header files.

Many (all) bugs have been removed, source code has been formatted, and the project has been configured to compile both 32-bit and 64-bit binaries.

ippolit 121724     3095 :  16384 (+8129,=2083,-6172),  56.0 %
vs.                     :  games (    +,    =,    -),   (%) :   Diff,  SD, CFS (%)
berserk-8               :   2048 (   47,  107, 1894),   4.9 :   -520,  12,    0.0
fire-8242022            :   2048 (   47,  237, 1764),   8.1 :   -426,  10,    0.0
fizbo-2                 :   2048 (  840,  318,  890),  48.8 :     -9,   5,    5.1
senpai-2.0              :   2048 (  763,  508,  777),  49.7 :     -2,   5,   31.6
hakkapeliitta-3.22      :   2048 ( 1150,  366,  532),  65.1 :   +109,   5,  100.0
quazar-0.4              :   2048 ( 1584,  293,  171),  84.5 :   +297,   6,  100.0
leorik-2.2              :   2048 ( 1776,  172,  100),  90.9 :   +404,  10,  100.0
coiled-1.1              :   2048 ( 1922,   82,   44),  95.8 :   +551,  14,  100.0

https://github.com/FireFather/ippolit/releases/download/121724/ippolit_121724.exe
https://github.com/FireFather/ippolit/archive/refs/tags/121724.zip
https://github.com/FireFather/ippolit/archive/refs/tags/121724.tar.gz

Author(s): Rei Meguro (USA)
Release Date: 2024-12-16
Language: C++
Protocol: UCI
Repo Owner: Orbital-Web
Repo URL: https://github.com/Orbital-Web/Raphael

Raphael is a UCI Chess Engine built using C++ and Disservin’s Chess Library. It also comes with a GUI built using SFML.

Changelog

Compiled with -O3 and -DNDEBUG flag for considerably faster code. Reduced size of transposition table, effectively increasing hash table entry count by 1.5x.

Note: there is no comparison with previous versions as the above changes affect all versions (roughly) equally, though the playing strength of the engine should have improved (will test soon).

https://github.com/Orbital-Web/Raphael/releases/download/v1.7.6/main
https://github.com/Orbital-Web/Raphael/releases/download/v1.7.6/main.exe
https://github.com/Orbital-Web/Raphael/releases/download/v1.7.6/Raphael1.7.6.1
https://github.com/Orbital-Web/Raphael/releases/download/v1.7.6/Raphael1.7.6.1.exe
https://github.com/Orbital-Web/Raphael/archive/refs/tags/v1.7.6.zip
https://github.com/Orbital-Web/Raphael/archive/refs/tags/v1.7.6.tar.gz

Author(s): Jon Dart (USA)
Release Date: 2024-12-16
Language: C++
Protocol: UCI/XB
Repo Owner: jdart1
Repo URL: https://github.com/jdart1/arasan-chess
Repo URL: https://www.arasanchess.org/old_downld.shtml

Changes in Arasan 25.0:

  1. Use a single “Book variety” option to control move selection from the book
  2. Some changes to book move selection logic
  3. Fix Intel oneAPI compiler support. Add support for CSSPGO with Intel/clang.
  4. Fixes/updates to selfplay utility. Support output in the format used by bullet.
  5. Add SyzygyUse50MoveRule and SyzygyProbeDepth options for CECP
  6. Make NNUE usage non-optional. Fail on startup if network cannot be loaded.
  7. arasan.rc is no longer loaded by the engine, by default. Auto-loading (the prior behavior) can be enabled via the -a command-line option, or use -r to select a specific file.
  8. Make eval command evaluate current position, like Stockfish
  9. Change SyzygyTbPath option to SyzygyPath, for conformity to Stockfish and most other engines
  10. New network architecture and network
  11. Changes to history score computation
  12. Use capture history for move ordering
  13. Implement a parameter tuning framework for search parameters, tune some using Lakas (https://github.com/jdart1/Lakas)
  14. Changes to static null pruning, adjust margins
  15. Windows GUI sources are now included in the repo
  16. GUI can set some options formerly only settable via arasan.rc

There is also an update to the Arasan test suite, available here: https://arasanchess.org/testsuite.shtml.

Test results of version 25.0 against version 24.2, tc 1:0+0.8, 512MB, 8moves_v3.pgn book:

Elo: 19.13 +/- 6.86, nElo: 42.52 +/- 15.23
LOS: 100.00 %, DrawRatio: 79.50 %
Games: 2000, Wins: 260, Losses: 150, Draws: 1590, Points: 1055.0 (52.75 %)

https://github.com/jdart1/arasan-chess/archive/refs/tags/v25.0.zip
https://github.com/jdart1/arasan-chess/archive/refs/tags/v25.0.tar.gz
https://arasanchess.org/arasan25.0.exe
https://arasanchess.org/arasan25.0.zip
https://arasanchess.org/arasan-linux-binaries-25.0.tar.gz
https://arasanchess.org/arasan25.0-m1.dmg
https://arasanchess.org/arasan25.0-intel.dmg

Author(s): Aron Petkovski (USA)
Release Date: 2024-12-16
Language: C++
Protocol: UCI
Repo Owner: aronpetko
Repo URL: https://github.com/aronpetko/integral

This update should let Integral breach into the top 15, maybe even top 10 if it scales well enough. It’s genuinely crazy seeing where this project is now.

Notable things in this update are:

  • Support for Multi-PV
  • Many search improvements and an SPSA tune
  • Bug fixes for wrong scores returned when using Syzygy tablebases

And of course, special thanks to everyone in my OpenBench instance and the kind, helpful people in the Stockfish discord.

Progression Tests

STC

Elo   | 48.98 +- 6.48 (95%)
Conf  | 8.0+0.08s Threads=1 Hash=16MB
Games | N: 3006 W: 946 L: 525 D: 1535
Penta | [5, 197, 700, 574, 27]
https://chess.aronpetkovski.com/test/6574/

LTC

Elo   | 52.95 +- 6.17 (95%)
Conf  | 40.0+0.40s Threads=1 Hash=32MB
Games | N: 3002 W: 963 L: 509 D: 1530
Penta | [1, 185, 679, 631, 5]
https://chess.aronpetkovski.com/test/6601/

https://github.com/aronpetko/integral/releases/download/v6/integral_avx2.exe
https://github.com/aronpetko/integral/releases/download/v6/integral_avx2_bmi2.exe
https://github.com/aronpetko/integral/releases/download/v6/integral_avx512.exe
https://github.com/aronpetko/integral/releases/download/v6/integral_sse41_popcnt.exe
https://github.com/aronpetko/integral/releases/download/v6/integral_vnni512.exe
https://github.com/aronpetko/integral/archive/refs/tags/v6.zip
https://github.com/aronpetko/integral/archive/refs/tags/v6.tar.gz

Author: Evan Fung
Release Date: 2024-12-16
Language: C++
Protocol: UCI
Repo Owner: 0mn1verze
Repo URL: https://github.com/0mn1verze/Maestro-Chess-Engine

Fix Logs

  • Added singular extension search
  • Fixed capture move bug in late move reductions
  • Refactored files like hash.cpp and eval.cpp
  • Improved staged move generation
  • Fixed other search bugs

Match Results

Maestro vs Rybka 2.3.2a 64bit:

  • 0.30/0.3 time controls on a i7-10750H with turbo boost on
  • WDL ratio: 23 – 3 – 4

Use Tips

  • Put the exe file, nnue file, and the bin file in the same folder for it to run correctly.
  • Please see the manual for UCI Commands
  • Website Demo

Custom commands

  • “b” – print board
  • “bench” – benchmarking move generation using positions from bench.csv

Performance

  • Rough estimate of 3000 elo

https://github.com/0mn1verze/Maestro-Chess-Engine/releases/download/V1.3/bench.csv
https://github.com/0mn1verze/Maestro-Chess-Engine/releases/download/V1.3/Maestro.exe
https://github.com/0mn1verze/Maestro-Chess-Engine/releases/download/V1.3/nn-eba324f53044.nnue
https://github.com/0mn1verze/Maestro-Chess-Engine/releases/download/V1.3/OPTIMUS2403.bin
https://github.com/0mn1verze/Maestro-Chess-Engine/archive/refs/tags/V1.3.zip
https://github.com/0mn1verze/Maestro-Chess-Engine/archive/refs/tags/V1.3.tar.gz

Author(s): Mattia Giambirtone
Release Date: 2024-12-13
Language: Nim
Protocol: UCI
Repo Owner: nocturn9x
Repo URL: https://git.nocturn9x.space/nocturn9x/heimdall

This release addresses a bug that I had inadvertently introduced while refactoring Heimdall’s SMP functionality. For simplicity (and my own sanity), I have reverted the change and switched back to the old way of spawning threads, which means they are re-created at every go command (inefficient, but at least it works!)

Please refer to 1.2’s release notes for an accurate changelog and strength improvements

https://git.nocturn9x.space/nocturn9x/heimdall/archive/1.2.2.zip
https://git.nocturn9x.space/nocturn9x/heimdall/archive/1.2.2.tar.gz
https://git.nocturn9x.space/nocturn9x/heimdall/releases/download/1.2.2/heimdall-linux-amd64
https://git.nocturn9x.space/nocturn9x/heimdall/releases/download/1.2.2/heimdall-linux-amd64-modern
https://git.nocturn9x.space/nocturn9x/heimdall/releases/download/1.2.2/heimdall-windows-amd64.exe
https://git.nocturn9x.space/nocturn9x/heimdall/releases/download/1.2.2/heimdall-windows-amd64-modern.exe

Author(s): Alcides Schulz (USA)
Release Date: 2024-12-12
Language: C
Protocol: UCI
Repo Owner: alcides-schulz
Repo URL: https://github.com/alcides-schulz/Tucano

It now returns to the version 10.00 neural network architecture but with the incremental evaluation update, and other search improvements.

In this release you will find the network file “tucano_nn03.bin” that has to be saved to the same folder as the executable file, or can be indicated in the parameters. Please review the readme.md file for more information.

Also includes executables for windows and linux (centos).
This version is stronger than previous 11.00 version.

https://github.com/alcides-schulz/Tucano/releases/download/12.00/tucano.1200.zip
https://github.com/alcides-schulz/Tucano/archive/refs/tags/12.00.zip
https://github.com/alcides-schulz/Tucano/archive/refs/tags/12.00.tar.gz