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.
27 figure.diagram-container
29 | fen:r3kbnr/pp3ppp/3p4/4p3/8/8/PPPPPPPP/R1BQKBNR:
30 figcaption After the moves 1.Nc3 d6?? 2.Nd5 e5 3.Nxc7
35 Possible starting point Wikipedia page ?