private char scanDiagonal(Diagonal diagDirection) {
		final boolean isLeftDiagonal = diagDirection == Diagonal.Left;

		final char startToken = _board[0][isLeftDiagonal ? 0 : _board.length - 1];

		int row = 1;
		int col = isLeftDiagonal ? 1 : _board.length - 2;

		while (row < _board.length && col >= 0) {
			if (_board[row][col] != startToken) {
				return NO_WINNER_CHAR;
			}

			++row;
			col = col + (isLeftDiagonal ? 1 : -1);
		}

		return startToken;
	}