Modern chess is a chess variant played on a 9×9 board. The game was invented by Gabriel Vicente Maura in 1968. Besides the usual set of chess pieces, each player has an additional piece with a corresponding pawn:
The first match was played in Madrid at Escuela de Bellas Artes de San Fernando's cafe on March 18, 1968. The players were Gabriel Vicente Maura himself (White), and Bonifacio Pedraz Cabezas (Black).
The starting setup is as shown. All the standard rules of chess apply, along with the following special rules:
- A player can castle either ministerside (notated "0-M-0") or queenside (notated "0-Q-0"); in either case the king slides two squares toward the castling rook.
- When reaching the final rank, pawns promote as normal, and can also promote to prime minister.
In response to criticism that bishops are restricted to only one square color, the inventor proposed an optional new rule, if the players agree:
- One bishop may switch its position with a piece adjacent to it, provided that the bishop and the piece adjacent have not yet moved in the game. The switch is counted as a normal move.
- Pritchard, D. B. (1994). "Modern Chess (II)". The Encyclopedia of Chess Variants. Games & Puzzles Publications. ISBN 0-9524142-0-1.
- Pritchard, D. B. (2007). "Modern Chess [Maura]". In Beasley, John (ed.). The Classified Encyclopedia of Chess Variants. John Beasley. ISBN 978-0-9555168-0-1.