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Official release version of Stockfish 17 Bench: 1484730 --- Stockfish 17 Today we have the pleasure to announce a new major release of Stockfish. As always, you can freely download it at https://stockfishchess.org/download and use it in the GUI of your choice. Don’t forget to join our Discord server[1] to get in touch with the community of developers and users of the project! *Quality of chess play* In tests against Stockfish 16, this release brings an Elo gain of up to 46 points[2] and wins up to 4.5 times more game pairs[3] than it loses. In practice, high-quality moves are now found in less time, with a user upgrading from Stockfish 14 being able to analyze games at least 6 times[4] faster with Stockfish 17 while maintaining roughly the same quality. During this development period, Stockfish won its 9th consecutive first place in the main league of the Top Chess Engine Championship (TCEC)[5], and the 24th consecutive first place in the main events (bullet, blitz, and rapid) of the Computer Chess Championship (CCC)[6]. *Update highlights* *Improved engine lines* This release introduces principal variations (PVs) that are more informative for mate and decisive table base (TB) scores. In both cases, the PV will contain all moves up to checkmate. For mate scores, the PV shown is the best variation known to the engine at that point, while for table base wins, it follows, based on the TB, a sequence of moves that preserves the game outcome to checkmate. *NUMA performance optimization* For high-end computers with multiple CPUs (typically a dual-socket architecture with 100+ cores), this release automatically improves performance with a `NumaPolicy` setting that optimizes non-uniform memory access (NUMA). Although typical consumer hardware will not benefit, speedups of up to 2.8x[7] have been measured. *Shoutouts* *ChessDB* During the past 1.5 years, hundreds of cores have been continuously running Stockfish to grow a database of analyzed positions. This chess cloud database[8] now contains well over 45 billion positions, providing excellent coverage of all openings and commonly played lines. This database is already integrated into GUIs such as En Croissant[9] and Nibbler[10], which access it through the public API. *Leela Chess Zero* Generally considered to be the strongest GPU engine, it continues to provide open data which is essential for training our NNUE networks. They released version 0.31.1[11] of their engine a few weeks ago, check it out! *Website redesign* Our website has undergone a redesign in recent months, most notably in our home page[12], now featuring a darker color scheme and a more modern aesthetic, while still maintaining its core identity. We hope you'll like it as much as we do! *Thank you* The Stockfish project builds on a thriving community of enthusiasts (thanks everybody!) who contribute their expertise, time, and resources to build a free and open-source chess engine that is robust, widely available, and very strong. We would like to express our gratitude for the 11k stars[13] that light up our GitHub project! Thank you for your support and encouragement – your recognition means a lot to us. We invite our chess fans to join the Fishtest testing framework[14] to contribute compute resources needed for development. Programmers can contribute to the project either directly to Stockfish[15] (C++), to Fishtest[16] (HTML, CSS, JavaScript, and Python), to our trainer nnue-pytorch[17] (C++ and Python), or to our website[18] (HTML, CSS/SCSS, and JavaScript). The Stockfish team [1] https://discord.gg/GWDRS3kU6R [2] https://tests.stockfishchess.org/tests/view/66d738ba9de3e7f9b33d159a [3] https://tests.stockfishchess.org/tests/view/66d738f39de3e7f9b33d15a0 [4] https://github.com/official-stockfish/Stockfish/wiki/Useful-data#equivalent-time-odds-and-normalized-game-pair-elo [5] https://en.wikipedia.org/wiki/Stockfish_(chess)#Top_Chess_Engine_Championship [6] https://en.wikipedia.org/wiki/Stockfish_(chess)#Chess.com_Computer_Chess_Championship [7] https://github.com/official-stockfish/Stockfish/pull/5285 [8] https://chessdb.cn/queryc_en/ [9] https://encroissant.org/ [10] https://github.com/rooklift/nibbler [11] https://github.com/LeelaChessZero/lc0/releases/tag/v0.31.1 [12] https://stockfishchess.org/ [13] https://github.com/official-stockfish/Stockfish/stargazers [14] https://github.com/official-stockfish/fishtest/wiki/Running-the-worker [15] https://github.com/official-stockfish/Stockfish [16] https://github.com/official-stockfish/fishtest [17] https://github.com/official-stockfish/nnue-pytorch [18] https://github.com/official-stockfish/stockfish-web |
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Stockfish
A free and strong UCI chess engine.
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Overview
Stockfish is a free and strong UCI chess engine derived from Glaurung 2.1 that analyzes chess positions and computes the optimal moves.
Stockfish does not include a graphical user interface (GUI) that is required to display a chessboard and to make it easy to input moves. These GUIs are developed independently from Stockfish and are available online. Read the documentation for your GUI of choice for information about how to use Stockfish with it.
See also the Stockfish documentation for further usage help.
Files
This distribution of Stockfish consists of the following files:
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README.md, the file you are currently reading.
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Copying.txt, a text file containing the GNU General Public License version 3.
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AUTHORS, a text file with the list of authors for the project.
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src, a subdirectory containing the full source code, including a Makefile that can be used to compile Stockfish on Unix-like systems.
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a file with the .nnue extension, storing the neural network for the NNUE evaluation. Binary distributions will have this file embedded.
Contributing
See Contributing Guide.
Donating hardware
Improving Stockfish requires a massive amount of testing. You can donate your hardware resources by installing the Fishtest Worker and viewing the current tests on Fishtest.
Improving the code
In the chessprogramming wiki, many techniques used in Stockfish are explained with a lot of background information. The section on Stockfish describes many features and techniques used by Stockfish. However, it is generic rather than focused on Stockfish's precise implementation.
The engine testing is done on Fishtest. If you want to help improve Stockfish, please read this guideline first, where the basics of Stockfish development are explained.
Discussions about Stockfish take place these days mainly in the Stockfish Discord server. This is also the best place to ask questions about the codebase and how to improve it.
Compiling Stockfish
Stockfish has support for 32 or 64-bit CPUs, certain hardware instructions, big-endian machines such as Power PC, and other platforms.
On Unix-like systems, it should be easy to compile Stockfish directly from the
source code with the included Makefile in the folder src. In general, it is
recommended to run make help to see a list of make targets with corresponding
descriptions. An example suitable for most Intel and AMD chips:
cd src
make -j profile-build ARCH=x86-64-avx2
Detailed compilation instructions for all platforms can be found in our documentation. Our wiki also has information about the UCI commands supported by Stockfish.
Terms of use
Stockfish is free and distributed under the GNU General Public License version 3 (GPL v3). Essentially, this means you are free to do almost exactly what you want with the program, including distributing it among your friends, making it available for download from your website, selling it (either by itself or as part of some bigger software package), or using it as the starting point for a software project of your own.
The only real limitation is that whenever you distribute Stockfish in some way, you MUST always include the license and the full source code (or a pointer to where the source code can be found) to generate the exact binary you are distributing. If you make any changes to the source code, these changes must also be made available under GPL v3.