By James Lummel
Played with 3 boards (1 common board and 1 hidden board each per player), referee and tokens to represent unmasking pieces (ideal would be software implementation).
Standard Chess setup.
Standard Chess pieces.
Standard Chess rules except as follows.
Masking = moving in stealth (transferred to stealth, or hidden, board).
You can only mask or unmask any piece (except for the King) that was just moved, at the end of the move.
King can't mask, all other pieces can.
While in stealth, pieces MUST move in normal fashion on their stealth board.
Masked pieces move on a stealth board that is empty of the other player's pieces. So the other player's pieces don't get in the way, but they cannot be taken while you are masked either. On the main board masked pieces DO NOT count and cannot block (i.e. - they are not there to block because they are on the stealth board).
A piece can't be unmasked in an occupied square, only in an empty square (at the END of
that piece's move).
Upon unmasking, a piece can be represented as and move as a Pawn (though not necessary). But once a piece moves regularly, the piece is represented as itself until masked again. NOTE - unless the piece was originally a Pawn it can't be turned into a Queen on reaching the other side, only REAL Pawns can do that.
For Pawns to be turned into Queens they must not be masked when reaching the other side. A Pawn reaching the other side while masked and then unmasking is prohibited from being turned into a Queen - only Pawns reaching the other side while unmasked can be Queened.
Any number of pieces can be masked at any one time.
Standard Chess equipment.