Through the Looking-Glass

This variant was inspired by few games of Alice Chess where I played with wrong rules. It come out a different game where two players struggle in an interdimensional mostly blind fight.

Perhaps it is impossible to play, but maybe it is actually interesting. So here it is.

Setup

The equipment needed is two FIDE Chess boards and one set of pieces. The players should be in front of a different board and not being able to see the other player board, but they have to be able to hear each other clearly. To make the communication easier boards with numbered rows and columns are preferable.

Since there is hidden information players will probably need some extra equipment to take notes, remember position of pieces, and whatnot. Possibly even an extra board can be useful, but it's not part of the game it is just a way to help players to keep track of the game situation. The point is that this is not just permitted, but encouraged. If you keep track of all the information given you should always be able to know where your pieces are, even in the other world.

The two battle fields are rules-wise identical, but we will call one the Real world the other the Mirror world. Each player prepares his army in his board. So, the Black will have the pieces in row 7 and 8 of the Mirror world, the White in row 1 and 2 of the Real world.

The starting position is fluid and decided autonomously by the two players. Players place the Pawns in the second rank and pieces in the first rank. They start with a Bishop in one of the black squares, the second Bishop in one of the white squares, the two Knights and Queen anywhere in the remaining six squares, and finally Rook, King, and second Rook in this order in the remaining three squares. Of course, this idea is inspired by Chess 960, but unlike the original the two players might have different setups.

The fact players do not see the other board and the starting position is non-standard is the source of the hidden information.

To be comfortable a possible playing position is having the two players one sitting near the other with the boards in front of them, flipped so White keeps the row 1 nearby, and Black keep row 8. Just add a panel that covers the boards. However the players are nearby, so the can easily pass pieces, communicate, and use the clock. Don't glance!

Here is a little scheme to explain, the "I" between the two boards represent a panel:

--------------------
   ---   I  ---
  I   I  I I   I
  I   I  I I   I
   ---   I  ---
  Real   I  Mirror
         I
       clock
--------------------
Mr.White   Mr.Black

Rules

Most of the rules are the same of FIDE Chess, the main differences are that the pieces fall between worlds, a player can see only his world and get fragmentary information about the other, and there is no check or checkmate.

A player loses when his King is captured or when he shows that he lost control of his army.

Portals connect the same numbered cells between the two worlds; for example, the square A1 in the Real world is connected to the square A1 in the Mirror world and vice versa.

Moves

Players move like in FIDE Chess, but when the piece arrive in his final square you ask the other player if there is already a piece in the relative square of the other world. If there are no pieces the player give the piece to the adversary and the piece get placed on the other world connected square.

When a piece changes world, the player who see the board has to state the name and position of any adversary piece that the newly arrived piece attacks. For Pawns the players state also the content of the square in front of the Pawn. This happens even if a friendly piece has come back and attacks an adversary piece in your world.

To move pieces on the other world the moving player has to ask the adversary to move for him; in order to do so the moving player have to tell the starting square and the destination square. After the move the piece can fall back in the other world as explained before.

However the move might not be possible for few reasons: the piece can move in the expected direction but it cannot reach the final square, a piece of the correct color is not in the starting square, or it cannot move at all in that direction.

In the former case the adversary player executes the move as long as possible and, depending what stopped it, the piece will stop with a capture or just stop before a piece of the same color.

In the other cases the player failed to give a meaning order and shown he lost control of the situation. He gets a Strike, the adversary mention that the move is impossible and the player tries again.

If during the game a player gets a third Strike, the game is lost for him.

Strike example

White see the Real world and Black see the Mirror world. There is a Black Knight in Real world F4. White moves a Pawn from Real D2 to Real D4, the piece falls in Mirror D4. Black moves (asking the White player to move) the Knight to Real D5 and the Knight also falls in Mirror D5 so it's now in front of the Pawn.

The two players continue a bit and White ask the other player to move the Pawn from D4 to D5 in the Mirror world. However this move it's not possible as there is a Knight in front. The black player mention the move it's impossible and White gets a Strike.

If if you write down your moves and all the information you get from the adversary player and never do mistakes the Strikes won't happen. This is intended, the hidden information comes from the unusual setup. Pieces will appear in your world in unpredictable ways, but slowly you should get grip of where everything is.

Notes

After castling the moving player asks about both portals, the King, the Rook, or both pieces might change world.

En passant capture is possible only if the two involved Pawns are in the same board. The fact that the Pawn that did the double move changes world is irrelevant as the other Pawn would capture it when it passes. The capturing Pawn might change world after the capture, as usual.

Knights, the King, and Pawns (a part of the starting move) cannot make a shorter move because they got interrupted by an unexpected piece.

The captured pieces should be somewhere both players can easily see.

A player can ask anytime if there are any legal move for his pieces in the other board, the player has simply to answer "yes" or "no," no need to give more details. If there are no legal moves in both boards the game is a draw by stalemate.

Since players cannot see the opponent board and the starting setup is unusual cheating is well possible, for example exchanging two pieces you did not move yet. However, if you really consider to cheat at unknown Chess variants please go very far away.

The basic idea is fairly general. If it works works for FIDE Chess, it should also works for other Fairy pieces variants like Seirawan Chess or for faster games like Extinction Chess.

If you don't like the Strike idea, there is an alternative. If the asked move has no meaning (i.e., it's impossible even partially) the player lost the chance to move. However, zugzwang is enforced so the adversary will move for you, if the adversary also fails, you can try again. This idea emulates that the impossible order was misinterpreted by your army in the worst possible way.