A list of hints in any cell represents the variety of possible candidates for this cell. If one of the possible candidates in the cell (a hint) has the same value as any cell in the same box, row, or column, this hint is a conflicting candidate, and it should be removed from the list. A picture on the left represents an example of the conflicting candidates. There is a number 1 in the cell H7. According to Sudoku rules, number 1 can appear only once in a box (3*3), in a row H, and in a column 7. All hints '1'
marked with red are the Conflicting Candidates, and they should be removed from the list of potential candidates.