<P> Over time, other improvements have been suggested, and indeed the Falphabeta (fail - soft alpha - beta) idea of John Fishburn is nearly universal and is already incorporated above in a slightly modified form . Fishburn also suggested a combination of the killer heuristic and zero - window search under the name Lalphabeta ("last move with minimal window alpha - beta search"). </P> <P> Stockfish (chess) is a C++ open source chess program that implements the Alpha Beta pruning algorithm . Stockfish is a mature implementation that is rated as one of the strongest chess engines available today as evidenced by it winning the Top Chess Engine Championship in 2016 and 2017 . </P> <P> Since the minimax algorithm and its variants are inherently depth - first, a strategy such as iterative deepening is usually used in conjunction with alpha--beta so that a reasonably good move can be returned even if the algorithm is interrupted before it has finished execution . Another advantage of using iterative deepening is that searches at shallower depths give move - ordering hints, as well as shallow alpha and beta estimates, that both can help produce cutoffs for higher depth searches much earlier than would otherwise be possible . </P> <P> Algorithms like SSS *, on the other hand, use the best - first strategy . This can potentially make them more time - efficient, but typically at a heavy cost in space - efficiency . </P>

Where does the value of alpha-beta search get updated