Marseillais chess (also called Double-Move chess) is a chess variant in which each player moves twice per turn. The rules of the game were first published in Marseillais local newspaper Le Soleil in 1925. This chess variant became quite popular in the late 1930s with such chess grandmasters as Alexander Alekhine, Richard Réti, Eugene Znosko-Borovsky, and André Chéron playing it.
A player can either move one piece twice or move two different pieces on his turn. Castling is considered as a single move.
When a player gives a check on the first move, he loses the second move of his turn. If a player is in check, he must move out of check on the first move of the turn. It is not allowed to move the king into the check on the first move of the turn and then move out of the check on the second one.
En passant capture is allowed even if the opponent moved the corresponding pawn on the first move of the previous turn. However, en passant capture must be made on the first move of the turn. When two pawns can be captured en passant after opponents move, both of them can be captured.
To avoid too much advantage for White, usually a balanced version of the game is played. In the balanced version, White makes only one move on the first turn. The moves are made in the following order: White, Black, Black, White, White, Black, Black, etc. This rule was introduced in 1963 by Robert Bruce and since then gained a wide acceptance.
- Progressive chess—a chess variant in which players, rather than just making one move per turn, play progressively longer series of moves. The game starts with White making one move, then Black makes two consecutive moves, White replies with three, Black makes four, and so on.
- Pritchard, D. B. (1994). The Encyclopedia of Chess Variants. Games & Puzzles Publications. pp. 187–90. ISBN 0-9524142-0-1.
- Pritchard, D. B. (2000). "§5 Marseillais Chess". Popular Chess Variants. B.T. Batsford Ltd. ISBN 0-7134-8578-7.
- Pritchard, D. B. (2007). Beasley, John, ed. The Classified Encyclopedia of Chess Variants. John Beasley. pp. 21–23. ISBN 978-0-9555168-0-1.