Alice's ArmyIn Alice's Chess, every time a piece moves it moves through the looking glass, and changes from one alternate universe to another.
For example, before the first move the alternate board is empty, but after 1. e2-e4, there is a single White Pawn on the alternate board. After 1. e4 e5 2. Qh5 Nc6 3. Qh5:e5, the White Queen comes back to the original board and it is checkmate.
In the context of Chess Variants with Different Armies, we have to wonder if Alice's Chess is stronger than FIDE Chess.
The Alician Army has a whole extra board to play with, a board where its pieces cannot be threatened or blocked by the FIDE pieces; but on the other hand, when the Alician pieces are on the extra board, they can neither threaten nor block the FIDE pieces.
The Rule of IdentityThe usual rule is that both armies must use the same Kings and Pawns. This seems like a good rule in this case, because the player of Alice's Army could simply put the King on the alternate board and leave it there "forever", immune to check.
However, it is not certain that this rule is necessary! Certainly it would be a wilder variant to play flat-out Alice on one side, with Alician Pawns and an Alician King.
Later on, I give a Sample Game with Alician King, which seems to demonstrate that the Alician King is too strong.
The Rule Of SimultaneityIn addition, one further rule needs to be clarified. In an example where White plays FIDE and Black plays Alice's Army, after 1. e4 e5, is the move 2. e4-e5 a legal move?
In Alice's Chess, you could reach this Pawn formation with 1. e3 e5 2. e4 Nc6 and 3. e4-e5 is not a legal move because the Pawn would first arrive on e5 of the original board and then it would need to step through the looking glass onto the square e5 of the alternate board -- but the destination is occupied and so the move is illegal!
However, in our example, the Pawn that goes to e5 does not need to go onto the other board, and so perhaps there is no reason for the move to be illegal.
Surprise! The White Pawn at e5 would be immune from capture! This would be unfair, and so it is illegal for White to play a piece to any square that is occupied on the other board.
The Rule of SubstitutionOf course, instead of playing a game where one side uses the FIDE-chess army and the FIDE rules, but the other side uses the FIDE-chess army and Alician rules, it might be considerably more interesting to play a game where one side uses the non-Alician Nutty Knights and the other side uses the Alician Colorbound Clobberers!
En PassantPhilidor explained that the reason for the en passant capture is that it is not fair for a Pawn to avoid another Pawn's threat to capture it by making its 2-step move.
Therefore, the rule must be that Alician Pawns are immune to en passant capture, but FIDE Pawns are vulnerable!
This rule, like the whole game, is deliciously complex and arcane.
Sample Game with Alician KingI was never very good at Alice's Chess, so this sample game might not be very strong.
White plays FIDE, Black plays Alician, both use the FIDE army.
1. e4 e5 2. Qh5 Qh4!
Maybe not a good move, but a surprising one.
3. Bc4 Nf6
Note that 3...Qe7 4. B:f7+ Q:f7 is illegal because the Queen disappears onto the other board and leaves the King in check.
4. Q:f7+ Kd8 5. Nf3 Qg4!
Threatens to take the Knight and run away to safety on the other board.
6. Nd4!? Q:e4 7. Nb5 Nc6 8. N:c7 Rb8 9. O-O Bc5!? 10. Q:g7 Rg8 11. Q:h7 Rb4
Black could not keep all his Pawns, but now plans to use the extra board to develop a smashing attack. White cannot defend any pieces against the hit-and-run attack.
12. Bd5 Rg5 13. d4 R:g2 14. Nc3 Rg2-g4+ 15. Kh1 Rb4:d4
The threat is Rd4-h4, Rh4:h2, and Rh2-h3 mate. Although there are defenses, the position feels to me like Black is winning, and mainly because the Black King is so safe that there is no counterplay.
Sample Game with FIDE King and Alician Pawns1. e4 e5 2. Qh5 Qh4 3. Bc4 Nf6 4. Q:f7+ Kd8 5. d4
Threat 6. Bc1-g5 mate.
5. d4 Qg4 6. h3!
Summary of Sample GamesI was never very good at Alice's Chess.
In the second game, quite possibly my choice of Black's moves was awful and deserved to lose fast. Anyway, it did lose fast.
However, it certainly looks like having an Alician King with an Alician army is very strong, and also that having a normal King with an Alician army makes it hard to defend yourself.
Let's Try AgainThe first attempts indicated that Alician pieces are powerful attackers, but poor defenders.
The natural thing to try next would be to have a non-Alician King and Pawns, several non-Alician pieces for defense, and a few Alician pieces for offense; but the Alician pieces should not be *too* strong!
The result of this should be a game where both sides race to see who can give mate the faster.