El Ajedrecista
El Ajedrecista is a chess-playing automaton designed by the Spanish engineer and inventor Leonardo Torres Quevedo. First demonstrated in 1913 and later exhibited in Paris in 1914, it played a simplified chess endgame with three chess pieces on a dedicated board without any human operator. A second, more compact electromechanical version was completed around 1920.
After developing several algebraic calculators, Torres Quevedo began experimenting with automation and remote control during the first decade of the 20th century, developing a series of electromechanical "automaton" devices he collectively termed automática. In 1901 he presented his wireless remote-control system, the Telekine, which influenced his later work on chess automation, to remotely testing airships of his own creation without risking human lives. El Ajedrecista was completed in 1912 and exhibited for the first time in Valladolid, Spain in 1913. It created great excitement when it made its debut, at the French Academy of Sciences in 1914. The device could be considered the first computer game in history. It was widely mentioned in Scientific American as "Electric Automaton" on 16 May 1914 and as "Torres and His Remarkable Automatic Devices" on November 6, 1915. A second version, constructed in 1920 and presented in 1923, improved the reliability of the piece-movement system and eliminated visible mechanical supports through the use of electromagnets installed under a standard chessboard. In 1951, El Ajedrecista was presented at the influential French symposium Les Machines à calculer et la pensée humaine, where it mated Savielly Tartakower. The Austrian computer pioneer Heinz Zemanek played against the second version at the 1958 Brussels World's Fair. Both automatons are still in working condition and are on display at the Museo Torres Quevedo in the Escuela de Ingenieros de Caminos, Canales y Puertos in Madrid.
Its internal construction was published by Henri Vigneron. The pieces had a metallic mesh at their base, which closed an electric circuit that encoded their position in the board. When the black king was moved by hand, an algorithm calculated and performed the next best move for the white player. Torres defined two zones for use in his algorithm, the first consisting of the a-, b-, and c-files, and the second consisting of the f-, g-, and h-files. The algorithm is as follows: Torres Quevedo's automaton was built to play a fixed rook-and-king versus king endgame (white to move and win). The following diagrams and annotated line illustrate a complete forced mate in 21 moves from a typical starting position. This line is not necessarily the fastest mate, but it illustrates the type of deterministic endgame algorithm that El Ajedrecista implemented mechanically: restricting the opposing king with the rook, bringing the white king closer, driving the black king to the corner, and delivering a supported rook mate to the black King, who performs the best defense according to a chess endgame tablebase, recorded in Portable Game Notation.
