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an [[UCI]] compatible [[:Category:Open Source|open source]] chess engine developed by [[Tord Romstad]], [[Marco Costalba]], [[Joona Kiiski]] and [[Gary Linscott]] <ref>[http://www.talkchess.com/forum/viewtopic.php?t=58779 Stockfish 7] by [[Joona Kiiski]], [[CCC]], January 02, 2016</ref>, licensed under the [[Free Software Foundation#GPL|GPL v3.0]]. Marco forked the project from version 2.1 of Tord's engine [[Glaurung]], first announced by Marco in November 8, 2008 <ref>[http://www.talkchess.com/forum/viewtopic.php?t=24675 Stockfish 1.0] by [[Marco Costalba]], [[CCC]], November 02, 2008</ref>, and in early 2009 Joona's [[Smaug]], a further Glaurung 2.2 derivative, was incorporated <ref>[http://www.talkchess.com/forum/viewtopic.php?t=26971&start=1 Re: Smaug: a new chess engine based on glaurung] by [[Marco Costalba]], [[CCC]], March 12, 2009</ref> . Starting out among the top twenty engines, Stockfish has quickly climbed in [[Playing Strength|strength]] to become the world strongest chess entity as of 2018 - at least concerning the [[AlphaZero]] hype <ref>[[David Silver]], [[Thomas Hubert]], [[Julian Schrittwieser]], [[Ioannis Antonoglou]], [[Matthew Lai]], [[Arthur Guez]], [[Marc Lanctot]], [[Laurent Sifre]], [[Dharshan Kumaran]], [[Thore Graepel]], [[Timothy Lillicrap]], [[Karen Simonyan]], [[Demis Hassabis]] ('''2017'''). ''Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm''. [https://arxiv.org/abs/1712.01815 arXiv:1712.01815]</ref>, public available chess entity. The name "Stockfish" reflects the ancestry of the engine. Tord is Norwegian and Marco Italian, and there is a long history of [https://en.wikipedia.org/wiki/Stockfish stockfish] trade from Norway to Italy (to Marco's home town of [https://en.wikipedia.org/wiki/Vicenza Vicenza], in fact). Stockfish also referred another famous "little fish", the then strongest chess engine [[Rybka]]. In 2011, Marco Costalba and Joona Kiiski stepped down as Stockfish maintainers <ref>[http://www.talkchess.com/forum/viewtopic.php?t=40610 Stockfish on github] by [[Marco Costalba]], [[CCC]], October 02, 2011</ref>. From that, the project is being developed and maintained by the [[:Category:Stockfish Contributor|Stockfish community]].

A synergy effect with the [[Shogi]] community led to the promising branch of [[Stockfish NNUE]], courtesy of [[Hisayori Noda|Nodchip]], who introduced [[NNUE]] to Stockfish in 2019 <ref>[http://www.talkchess.com/forum3/viewtopic.php?f=2&t=74059 Stockfish NN release (NNUE)] by [[Henk Drost]], [[CCC]], May 31, 2020</ref>. On September 02, 2020, '''Stockfish 12''' was released with a huge jump in [[Playing Strength|playing strength]] due to NNUE and further [[Automated Tuning|tuning]] of the engine <ref>[https://stockfishchess.org/blog/2020/stockfish-12/ Stockfish 12], The Stockfish Team, [https://blog.stockfishchess.org/ Stockfish Blog], September 02, 2020</ref>. The release of '''Stockfish 13''' on February 19, 2021, has been triggered by the start of sales of the [[Fat Fritz#Fat Fritz 2|Fat Fritz 2]] engine by [[ChessBase]], based on a recent development version of Stockfish with minor modifications <ref>[https://stockfishchess.org/blog/2021/stockfish-13/ Stockfish 13], The Stockfish Team, February 19, 2021</ref>. '''Stockfish 14''', released on July 02, 2021, further improved due to efforts by [[Tomasz Sobczyk]] and [[Gary Linscott]] in designing a new NNUE architecture in conjunction with a [[GPU]] accelerated trainer written in [https://en.wikipedia.org/wiki/PyTorch PyTorch]. Further, the collaboration with the [[Leela Chess Zero]] team payed off, in providing billions of positions to train the new NNUE <ref>[https://stockfishchess.org/blog/2021/stockfish-14/ Stockfish 14], The Stockfish Team, July 02, 2021</ref>.