Editing Computer chess (section)

{{Short description|Computer hardware and software capable of playing chess}}
{{about||the film|Computer Chess (film)|chess played over the Internet|Online chess}}
[[Image:RS Chess Computer.JPG|thumb|1990s pressure-sensory chess computer with LCD screen]]
{{Chess programming series}}

'''Computer chess''' includes both hardware (dedicated computers) and [[software]] capable of playing [[chess]]. Computer chess provides opportunities for players to practice even in the absence of human opponents, and also provides opportunities for analysis, entertainment and training. Computer chess applications that play at the level of a [[Chess title|chess grandmaster]] or higher are available on hardware from [[supercomputer]]s to [[Smartphone|smart phones]]. Standalone chess-playing machines are also available. [[Stockfish (chess)|Stockfish]], [[Leela Chess Zero]], [[GNU Chess]], [[Fruit (software)|Fruit]], and other free open source applications are available for various platforms.

Computer chess applications, whether implemented in hardware or software, use different strategies than humans to choose their moves: they use [[Heuristic (computer science)|heuristic methods]] to build, search and evaluate [[Tree (data structure)|trees]] representing sequences of moves from the current position and attempt to execute the best such sequence during play. Such trees are typically quite large, thousands to millions of nodes. The computational speed of modern computers, capable of processing tens of thousands to hundreds of thousands of nodes or more per second, along with extension and reduction heuristics that narrow the tree to mostly relevant nodes, make such an approach effective.

The first chess machines capable of playing chess or reduced chess-like games were software programs running on digital computers early in the [[vacuum-tube computer]] age (1950s). The early programs played so poorly that even a beginner could defeat them.  Within 40 years, in 1997, [[chess engine]]s running on super-computers or specialized hardware were capable of [[Deep Blue versus Garry Kasparov|defeating even the best human players]]. By 2006, [[Human–computer chess matches|programs running on desktop PCs]] had attained the same capability. In 2006, [[Monty Newborn]], Professor of Computer Science at [[McGill University]], declared: "the science has been done". Nevertheless, [[solving chess]] is not currently possible for modern computers due to the [[Game complexity|game's extremely large number of possible variations]].<ref>{{cite web |last1=Sreedhar |first1=Suhas |title=Checkers, Solved! |url=https://spectrum.ieee.org/checkers-solved |website=IEEE Spectrum |date=2 July 2007 |publisher=Institute of Electrical and Electronics Engineers}}</ref>

Computer chess was once considered the "[[Drosophila]] of AI", the edge of [[knowledge engineering]]. The field is now considered a scientifically completed paradigm, and playing chess is a mundane computing activity.<ref>{{Cite journal|url=https://pubmed.ncbi.nlm.nih.gov/22530382/|pmid = 22530382|year = 2012|last1 = Ensmenger|first1 = N.|title = Is chess the drosophila of artificial intelligence? A social history of an algorithm|journal = Social Studies of Science|volume = 42|issue = 1|pages = 5–30|doi = 10.1177/0306312711424596|s2cid = 968033}}</ref>