I invented a similar chess variant that doesn't require a referee. All the pieces are one color, but on the bottom of the pieces you mark the true color (black

I invented a similar chess variant that doesn't require a referee. All the pieces are one color, but on the bottom of the pieces you mark the true color (black or white). When it's your turn, you can either move, or challenge your opponent that their last move was false. If you challenge, they turn over the piece they just moved. If it was their color, you lose your turn. If it was your color, they move the piece back and you get to move. Don't even get me started on Go Chess, a hybrid of Go and Chess played on a chess board with both Go and Chess pieces, where in the Go world even Chess pieces are treated as Go pieces.