Alice chess
Alice chess is a chess variant invented in 1953 by V. R. Parton which employs two chessboards rather than one, and a slight alteration to the standard rules of chess. The game is named after the main character "Alice" in Lewis Carroll's work Through the Looking-Glass, where transport through the mirror into an alternative world is portrayed on the chessboards by the after-move transfer of chess pieces between boards A and B.
This simple transfer rule is well known for causing disorientation and confusion in players new to the game, often leading to surprises and amusing mistakes as pieces "disappear" and "reappear" between boards, and pieces interposed to block attacks on one board are simply bypassed on the other. This "nothing is as it seems" experience probably accounts for Alice chess remaining Parton's most popular and successful variant among the numerous others he invented.
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.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.
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.
To demonstrate, if the above game continued 3. Nxf7, the knight transfers to board B. Then with Black to move, neither 3...Kxf7 nor 3...Bxf2+ are 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, even though a white pawn is on f2 on board A.
While making a move on the first board, the player is allowed to remain in 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.
Early mates
Fool's mate
Several exist; one is as follows: 1. e4 d5 2. Be2 dxe4 3. Bb5.At first glance, it might seem that Black can simply interpose a piece between White's bishop and his king to block the check. But any piece so interposed immediately "disappears" when it transfers to board B. And Black cannot escape check by fleeing to the opposite board via 3...Kd7, because the move is not a legal move on board A. Therefore, it is checkmate.
Another form of fool's mate: 1. e4 d6 2. Bc4 Qxd2? 3. Bb5#
And another: '''1. e4 e5 2. Qh5 Nf6? 3. Qxe5#'''
Scholar's mate
1. e4 h5 2. Be2 Rh4 3. Bxh5 Rxe4+ 4. Kf1 d5 5. Qe2? '5... Bh3#.1. d4 e6 2. Qd6 Be7? 3. Qe5+ Kf8 4. Bh6#'.
Example game
Paul Yearout vs. George Jelliss, 1996 AISE Grand Prix1. d3 Nf6 2. Nc3 c5 3. Qd2 Nc6 '''4. d4/A Rb8 5. e3 g5 6. f4 Rbg8/A 7. Nd5/A h6 8. Nf3 gxf4/A 9. Bxf4 Rg4 10. Be5/A Rh5 11. 0-0-0 11... Ne4/A 12. Bc7 Ra4/A 13. Ba6 Bg7 14. Bb5/A Rc4+ 15. Kb1/A Rf5/A 16. Ba5/A 16... Rxd5 17. Qxd5/A Qxa5 18. a3 Qd2/A 19. Qxd7+ Kf8 20. Qxg7/A Qc3 21. Rd8/A '''
Variations
Rule modifications have sprouted a number of variations of Alice chess.Looking glass Alice chess
The black army starts out on the opposite board.Ms. Alice chess
Null or zero moves are permitted. A king cannot escape check with a zero move, and castling is denied if either king or rook have made a zero move. By John Ishkan.O'Donohue chess
Alice chess rules, except that a move is permitted even though the square normally transferred to on the opposite board is occupied. By Michael O'Donohue.Duo chess
Black starts out on board B; transfers are optional; non-pawn pieces may make zero moves ; a king is checked when an opposing piece sits on the king's zero square; mate must cover the king's ability to flee via a zero move. By Jed Stone.Parton also introduced a smaller, 8×4 version of Alice chess. He also observed that Alice chess can be played using three boards instead of two.
Alice chess rules can be adopted by practically any other chess variant too, by simply doubling the number of gameboards in the variant and applying the piece transfer policy.