What is Stockfish?
Stockfish is a freely accessible chess engine and can be downloaded free of charge as a Open Source be used. In 2008, Marco Costalba developed Stockfish 1.0 from Ford Romstad's open source engine Glaurung. Soon after, Romstad and Joona Kiiski joined the Stockfish project. Through their efforts, together with a strong developer community, it quickly became the strongest open source chess program. Since then, Stockfish has continued to evolve, with new versions and offshoots being created all the time.
Also in 2022, the programme repeatedly tops the most rankings for computer chess in the world. The current version Stockfish 15 was released in April 2022 and is ranked number 1 on the Computer Chess Rating List (CCRL) with an Elo rating of 3542.
How does the chess programme work?
Stockfish is a "classic" chess engine that draws on a huge database of human-made moves and learns by playing against human players. It uses the Alpha Beta search algorithm to make decisions.
A significant Increasing the playing strength is possible through the cooperation with Leela Chess Zero since version Stockfish 12 to see. From now on, it uses the "Efficiently Updatable Neural Network" (NNUE) for position evaluation. In this way, Stockfish combines the immense computing power of "traditional" chess programmes with the superhuman evaluation possibilities of an artificial intelligence such as AlphaZero or Leela Chess Zero.
Stockfish against AlphaZero
Although Stockfish 8 was the strongest chess program in the world in 2017, it was clearly beaten by Google DeepMind's AlphaZero. This was to prove the superiority of AlphaZero's self-learning algorithm over Stockfish's human-trained algorithm.
AlphaZero's victory can be put into perspective, however, as immense computing power was spent on its training. As a result, it was able to play about 44 million chess games against itself in 9 hours. In addition, an outdated version of Stockfish 8 competed against AlphaZero.
Stockfish against Komodo
Komodo has been going toe-to-toe with Stockfish for several years. From 2016 to 2019, Komodo was the World Computer Chess Championship (WCCC) World Computer Chess Champion. The current version Dragon by Komodo 3, with an Elo rating of 3535, is only just behind Stockfish 15 (Elo rating 3542).
The playing style of both programmes differs somewhat. While Stockfish focuses on a precise and very tactical way of playing, Komodo is popular for its human style of play and its rating system. That is why many chess players support the developers of Komodo by buying the engine from them instead of just using Stockfish for free.
Stockfish can be downloaded as open source software free of charge from GitHub can be downloaded. Since the source code is openly available to everyone, new variants and offshoots of the chess programme are also constantly being created by the developer community.
Stockfish is not a complete chess programme, but a UCI (Universal Chess Interface). Therefore a graphical user interface (GUI) is also needed. Recommended are for example Scid, Cute Chess, eboard, Arena, Sigma Chess, Chess Partner or Fritz.
Stockfish 15 and other older versions are also available for Windows, Linux, macOS, Android and Apple iOS. official page of the project is available. This is also a UCI, so a GUI is needed again.