Editing Alice chess (section)

==Move rules==
At the beginning of the game, pieces start in their normal positions on board '''A''', while board '''B''' starts empty. At each turn, a player can choose whether to move on board '''A''' or '''B'''. Pieces move the same as they do in standard chess, but, at the completion of its move, a piece goes "through the looking-glass", transferring to the corresponding square on the opposite board. This simple change has dramatic impact on gameplay.

{{alice chess diagram
| tright
|
|rd|nd|bd|qd|kd|  |nd|rd
|pd|pd|pd|pd|  |pd|pd|pd
|  |  |  |  |  |  |  |
|  |  |  |  |nl|  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|pl|pl|pl|pl|pl|pl|pl|pl
|rl|nl|bl|ql|kl|bl|  |rl
<!-- Board A -->
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |pd|  |  |
|  |  |bd|  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
<!-- Board B -->
| Position after 1.Nf3 e6 2.Ne5 Bc5
}}
For example, after the opening moves '''1. Nf3 e6''', the white knight and black pawn transfer after moving on board '''A''' to their corresponding squares on board '''B'''. If the game continued '''2. Ne5 Bc5''', the knight returns to board '''A''' and the bishop finishes on board '''B''' (see diagram).

A move in Alice chess has two basic stipulations: the move must be legal on the board on which it is played, and the square transferred to on the opposite board must be vacant. Consequently, a piece can capture only on the board upon which it currently stands; it then transfers to the opposite board, as for a non-capturing move.

{{alice chess diagram
| tleft
|
|rd|nd|bd|qd|kd|  |nd|rd
|pd|pd|pd|pd|  |  |pd|pd
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|pl|pl|pl|pl|pl|pl|pl|pl
|rl|nl|bl|ql|kl|bl|bd|rl
<!-- Board A -->
|  |  |  |  |  |  |  |
|  |  |  |  |  |nl|  |
|  |  |  |  |pd|  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |
<!-- Board B -->
| Position after 3.Nxf7 Bg1
}}
To demonstrate, if the above game continued '''3. Nxf7''', the knight transfers to board '''B'''. Then with Black to move, both 3...Kxf7 and 3...Bxf2+ are not possible. Black cannot play 3...Qd4 either, since the queen may not hop over the pawn on d7. But the move '''3... Bg1''' ''is'' possible (see diagram), even a white pawn is on f2 on board '''A'''.  (The bishop move on board '''B''' is legal, and the square transferred to, g1 on board '''A''', is vacant.)

While making a move on the first board, the player is allowed to remain in [[Check (chess)|check]] on the second board, if the transferred piece then interposes to block the check.

A player must not be in check on the first board after making the move but before the transfer; thus the king cannot transfer out of check.

A player must also not be in check on either board after the transfer; thus they must not put themself in discovered check on the first board by making the transfer, and the king cannot transfer into check on the second board.

[[Castling]] is largely regarded as permitted in Alice chess; both king and rook would then transfer to the second board.

The ''[[en passant]]'' capture is normally excluded, but it can be included. In most such games, the target square is considered to be the square passed over on the first board, though opinions differ.<!-- {{efn|As in standard chess, moving into discovered check by capturing ''[[en passant]]'' is not allowed. In Alice chess, it is also not allowed if transfer either is blocked, or puts the player in discovered check.}} -->