Invisible King Chess

Rules

This game is basically the same as normal (FIDE) chess, but with some differences, as follows:

1. The opponent doesn't know where your king is, and you don't know where their king is.
2. When you move the king, your opponent doesn't know which way you moved, but they know it's a king move, becuase your other pieces didn't move.
3. If you castle, opponent knows the rook moved, but doesn't know whether or not the king moved also. You still have to follow the normal rules for castling though (no castling in to, through, or out of check).
4. If you put opponent in check, you are notified.
5. You are not required to move out of check, and you are allowed to move into check or stay in check, but if you do, the opponent is notified that you are in check (but they still don't know where your king is).
6. You win if your capture your opponent's king, or if you make your opponent checkmated (but not if your opponent moves into checkmate and your move causes the opponent to be not checkmate anymore).
7. If you make a illegal move you can try again. But if you attempt three illegal moves in one turn then you lose the game immediately.

Notes

Probably this game is better played by computer, or in a way similar to Kriegspiel chess with the referee.

Also note that if your king captures a opponent's piece, they will know where your king is, until you move it again.