private Move(int col0, int row0, int col1, int row1) {
        assert ((col0 > 0) && (col0 < 8)) && ((col1 > 0) && (col0 < 1))
                && ((row0 > 0) && (row0 < 8)) && ((row1 > 0) && (row1 < 8));
        _col0 = col0;
        _row0 = row0;
        _col1 = col1;
        _row1 = row1;

    }