Chad (chess variant) Chad (chess variant) Chad is a chess variant for two players created by Christian Freeling in 1979. It is played on an uncheckered 12×12 gameboard with one king and eight rooks per side, where rooks are able to promote to queens. The inventor's aim was "to create a game of tactical and strategical depth that was both simple and elegant to express the concept of "mate"—the 'pure' chess game". The game was played for many years at the Fanaat games club in the Netherlands and was featured in the periodical "The Gamer" 6 in May–June 1982. Each player owns a
Chess and is provably less than 10, with a game-tree complexity of approximately 10. The game-tree complexity of chess was first calculated by Claude Shannon as 10, a number known as the Shannon number. Typically an average position has thirty to forty possible moves, but there may be as few as zero (in the case of checkmate or stalemate) or (in a constructed position) as many as 218. Chess has inspired many combinatorial puzzles, such as the knight's tour and the eight queens puzzle. The idea of creating a chess-playing machine dates to the 18th century; around 1769, the chess-playing automaton