In abstract strategy board games, candidate moves are moves which, upon initial observation of the position, seem to warrant further analysis. Although in theory the idea of candidate moves can be applied to games such as Checkers, Go, and Xiangqi, it is most often used in the context of chess. An abstract strategy game is a board game with perfect information, no chance, and (usually) two players or teams. ... A board game is a game played with counters or pieces that are placed on, removed from, or moved across a board (a premarked surface, usually specific to that game). ... starting position on a 10×10 draughts board Draughts, also known as checkers, is a group of mental sport board games between two players which involve diagonal moves of uniform pieces and mandatory captures by jumping over the enemys pieces. ... Go is a board game for two players. ... Xiangqi (Chinese: 象棋; Pinyin: xiàngqí; Wade-Giles: hsiang4-chi2; ), is a two-player Chinese game in a family of strategic board games of which Western chess, Indian chaturanga, Japanese shogi, and the more similar Korean janggi are also members. ... Chess is an abstract strategy board game and mental sport for two players. ...

History

The idea of candidate moves was first put forth by Grandmaster Alexander Kotov in his book Think Like a Grandmaster. In it, Kotov recommended looking for several moves that seemed feasible- the so-called candidate moves- and then analyzing those moves one at a time. Although this idea had been practiced by expert chess players for some time, it had never been explicitly articulated, and was relatively unknown to players at the amateur level. The title Grandmaster is awarded to world-class chess masters by the world chess organization FIDE. Apart from World Champion, Grandmaster is the highest title a chess player can attain. ... Alexander Kotov (Александр Александрович Котов) (August 12, 1913 – January 8, 1981) was a chess grandmaster and author. ...

The idea quickly caught on, and is now considered standard doctrine among chess players at all levels. Many beginning players are taught about candidate moves as soon as they learn to play the game, and the idea is often referenced in other chess books.

Finding Candidate Moves

Finding the correct candidate moves is often one of the most difficult aspects of becoming a better chess player. Kotov, as well as other teachers, recommend using a system of pattern recognition, looking at the elements of the current position to determine what might be a feasible move. For example, if a player notices that his opponent's King is on the h8 square, and that his Knight is on f3, then a candidate move might be Ng5, a fairly common beginning to a sacrifice. Pattern recognition is a field within the area of machine learning. ... The King (♔♚) is the most important piece in the game of chess. ... Algebraic chess notation is the method used today by all competition chess organizations and most books, magazines, and newspapers to record and describe the play of chess games. ... The knight moves in an L shape. ... In chess, a tactic refers to a short sequence of moves which limits the opponents options and which results in tangible gain. ...

Once a player has found a good number of candidate moves (every position is different, although four to six moves is usually the norm), a player may then begin to systematically analyze these moves. The idea behind candidate moves is to help structure one's analysis and prevent it from becoming jumbled; inexperienced players who do not carefully consider candidate moves will often find themselves jumping between lines of analysis haphazardly.

Candidate Moves in Computer Chess

The ability of humans to find candidate moves remains one of the main differences between them and computers. Although early chess programmers made admirable efforts to make computers able to select candidate moves (see Type A versus Type B programs), they never played particularly well, and were soon supplanted by computers using brute-force algorithms (Shenk, 2006). The addition of Alphabeta algorithms made the latter type even more feasible. Many acknowledged that computers were simply not capable of performing the complex pattern recognition that was required to find appropriate candidate moves, and that it was easier to have computers perform simple exhaustive searches. 1990s Pressure-sensory Chess Computer with LCD screen The idea of creating a chess-playing machine dates back to the eighteenth century. ... 1990s Pressure-sensory Chess Computer with LCD screen The idea of creating a chess-playing machine dates back to the eighteenth century. ... In computer science, a brute-force search consists of systematically enumerating every possible solution of a problem until a solution is found, or all possible solutions have been exhausted. ... Alphabeta were a group of Israeli singers who won the Eurovision Song Contest in 1978 with Izhar Cohen. ...

Today, most chess programs still rely mainly on brute-force searches, but as search algorithms have improved, today's chess engines seem more and more to be using candidate moves in their analysis. Hydra, for example, is widely considered to be a "Type B" (candidate move finding) computer. A chess engine is a computer program that can play the game of chess. ... Hydra is a chess machine, designed by a team with Dr. Christian Chrilly Donninger, Ulf Lorenz, GM Christopher Lutz and Muhammad Nasir Ali. ...