Not to be nitpicky (well, maybe a little)... El Ajedrecista [1], a chess machine designed by Spanish engineer Leonardo Torres Quevedo in in 1912 and later impr

Not to be nitpicky (well, maybe a little)... El Ajedrecista [1], a chess machine designed by Spanish engineer Leonardo Torres Quevedo in in 1912 and later improved in 1915, defeated chess Grandmaster Savielly Tartakower in 1951 [2], a few years earlier than the unnamed lab assistant who lost to Los Alamos Chess. This would make Savielly the first human player defeated in a chess-like game. The lab assistant loss must have occurred sometime after 1956. To be fair, El Ajedrecista played a very limited game, only capable of playing a white king and rook against a black king moved by a human opponent. Still, I think it qualifies as a "chess like game" As a matter of casual trivia, El Ajedrecista inspired Claude Shannon, the founder of information theory, to build his own chess machine [3], which he named Caissac (after the goddess of chess Caissa [4]) in 1950. [1]. https://www.chessprogramming.org/El_Ajedrecista https://www.chessprogramming.org/El_Ajedrecista [2]. https://en.wikipedia.org/wiki/El_Ajedrecista https://en.wikipedia.org/wiki/El_Ajedrecista [3]. https://www.chess.com/article/view/the-man-who-built-the-chess-machine https://www.chess.com/article/view/the-man-who-built-the-che... [4]. https://en.wikipedia.org/wiki/Ca%C3%AFssa https://en.wikipedia.org/wiki/Ca%C3%AFssa