2 | Move twice at every turn.
7 li Chessboard: standard.
9 li Non-capturing moves: standard.
10 li Special moves: standard.
11 li Captures: standard.
12 li End of game: standard.
15 The only difference with orthodox chess is the double-move rule,
16 but this affects the game a lot.
21 TODO: explain, every turn twice except if check on 1st turn, or
22 very first move in game.
23 En-passant: possible in any order if 2 ep squares,
24 otherwise has to be the first move.
25 OK even if opponent moved his pawn at subturn 1.
28 PGN game notation: since there are two moves at each turn except on move 1,
29 a double move in the game is indicated as two comma-separated (ordered) moves,
30 as in 3.Na5,Bd3 e6,f4 (the two first are white moves,
31 the two others are black moves).
32 Sometimes a move gives check, or stalemate occurs after subTurn 1 :: just one move
34 figure.diagram-container
36 | fen:r1bqkbnr/pppp1p1p/2n5/4p2p/4P3/5N2/PPPP1PPP/RNB1KB1R:
37 figcaption After the moves 1.e4 e5,Nc6 2.Qh5,Nf3 g6,gxh5
43 a(href="https://www.chessvariants.com/multimove.dir/marseill.html")
45 | page on chessvariants.com.