public boolean onBoard() {
	return (((col + row) % 2 == 0) &&
		((col + row) >= 6)     &&  // northwest border
		((col + row) <= 22)    &&  // northeast border
		(col >= 1)             &&  // west border
		(col <= 9)             &&  // east border
		(row >= 1)             &&  // north border
		(row <= 17)            &&  // south border
		((row - col) <= 12)    &&  // southwest border
		((col - row) <= 4)     &&  // northeast border
		(! hole()));               // not a hole in the board
    }