private boolean checkVertical(int x, int y){
		// Find the minimum and maximum y values for this x which have the same mark
		int minY = y;
		while (minY > 0 && boardCells[x][minY - 1].equals(boardCells[x][y]))
			minY--;
		int maxY = y;
		while ((maxY + 1) < boardCells.length && boardCells[x][maxY + 1].equals(boardCells[x][y]))
			maxY++;
		// If the difference is larger than 4, we have 5 in a row
		return maxY - minY >= 4;

	}