Alice 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.
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.
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.
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.
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.
At first glance, it might seem that Black can simply interpose a piece between White's bishop and his king to block the check (for example, 3...Bd7 or 3...Nc6 or 3...c6).
But any piece so interposed immediately "disappears" when it transfers to board B.
Paul Yearout vs. George Jelliss, 1996 AISE Grand Prix [Annotations by George Jelliss; moves returning to board A are notated "/A".]
0-0-0 [diagram] (Perhaps judging that the activated black force now being on the second board the king might be safer there.
Qxd7+ Kf8 (I put these two moves in as an 'if...then' clause, but it seems Paul may not have noticed the discovered check, so perhaps I should have kept quiet!)
Rule modifications have sprouted a number of variations of Alice chess.
(A move consisting of piece transfer only – from the current square a piece sits on, to the corresponding square, if vacant, on the opposite board.)
Alice chess rules, except that a move is permitted even though the square normally transferred to on the opposite board is occupied.
Black starts out on board B; transfers are optional; non-pawn pieces may make zero moves (and may capture in so doing); 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.
Parton also introduced a smaller, 8×4 version of Alice chess (see diagram).
(Players then having a choice between two boards when transferring pieces.)
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 (for example, Raumschach using two 5×5×5 boards).
