public void unmake(Piece[][] board) {
        board[x1][y1] = Piece1;
        
        //System.out.println("Unmake: " + (Piece1.x == x2 && Piece1.y == y2));
        
        if (Piece2 != null) {
            board[x2][y2] = Piece2;
        }
        else
        {
            board[x2][y2] = null;
        }        
    }