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Official release version of Stockfish 17.1 Bench: 2030154 --- Stockfish 17.1 Today, we have the pleasure to announce Stockfish 17.1. As always, you can **freely** download it at [stockfishchess.org/download][1] and use it in the [GUI of your choice][2]. Join our [Discord server][3] to get in touch with the community of developers and users of the project! Quality of chess play In our testing against its predecessor, Stockfish 17.1 shows a consistent improvement in performance, with an [Elo gain of up to 20 points][4] and winning close to 2 times more game pairs than it loses. Update highlights New speedtest command The new `speedtest` command benchmarks your computer's performance (measured in nodes per second) using a realistic and stable test. To run it, you'll need [command line access][5]—give it a try and share your results with the community! Improved hardware support Stockfish is [no longer limited to 1024 threads][6] and will allow users to specify whatever their system is capable of. Additionally, hardware such as ppc64 and Loongson is now better supported at build time. Bug fixes for tablebase support Our previous release introduced improved engine lines (principal variations) ending in mate as soon as a mate score is announced. A side effect of this improvement was a [rare corner case][7] involving cursed tablebase wins, only relevant in correspondence chess when the 50-move rule does not apply, which has now been fixed. Relatedly, [time management][8] has also been improved to avoid potential time losses. Shoutouts Download page redesign We've redesigned the [download page][1] to address unclear wording and simplify a previously cluttered experience. The page now features a modernized layout, streamlined navigation, and clearer guidance to help you select the right binary for your system. Fishtest framework Our testing framework has been improved in various ways, both on the worker side, including the adoption of [Fastchess][9] as a new game manager, and on the server side, such as streamlined configuration. The reliable availability of testing resources is key for the progress of the engine. 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 [12k stars][10] 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][11] to contribute compute resources needed for development. Programmers can contribute to the project either directly to [Stockfish][12] (C++), to [Fishtest][13] (HTML, CSS, JavaScript, and Python), to our trainer [nnue-pytorch][14] (C++ and Python), or to our [website][15] (HTML, CSS/SCSS, and JavaScript). The Stockfish team [1]: https://stockfishchess.org/download [2]: https://official-stockfish.github.io/docs/stockfish-wiki/Download-and-usage.html#download-a-chess-gui [3]: https://discord.gg/GWDRS3kU6R [4]: https://tests.stockfishchess.org/tests/view/67e7d2fd6682f97da2178fbd [5]: https://official-stockfish.github.io/docs/stockfish-wiki/UCI-&-Commands.html#speedtest [6]:652a8874b5[7]:6c7c5c7e47[8]:0f9ae0d11c[9]: https://github.com/Disservin/fastchess [10]: https://github.com/official-stockfish/Stockfish/stargazers [11]: https://official-stockfish.github.io/docs/fishtest-wiki/Running-the-Worker.html [12]: https://github.com/official-stockfish/Stockfish [13]: https://github.com/official-stockfish/fishtest [14]: https://github.com/official-stockfish/nnue-pytorch [15]: https://github.com/official-stockfish/stockfish-web
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
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.
Acknowledgements
Stockfish uses neural networks trained on data provided by the Leela Chess Zero project, which is made available under the Open Database License (ODbL).