sudokUI › Sudoku techniques › Naked Triple
Naked Triple in sudoku
flip side of a hidden subset · in a line: Swordfish sideways · how it fits
Three empty cells in the same unit whose candidates, taken together, are exactly three digits X, Y and Z, though no single cell needs to hold all three.
Why it works
Three cells in one unit need three different digits, and only X, Y and Z are available, so those cells use up all three. Remove X, Y and Z from all other cells of each unit that contains all three cells.
How to spot it
In one unit, gather the cells with only two or three candidates and test whether three of them hold just three digits between them.
Worked example
Naked Triple: cells r7c4, r8c6, r9c4 contain only 2/6/7, removing those digits from the cells they all see. So 2 is removed from r9c6; 6 is removed from r7c5.
Practise it on a real puzzle. sudokUI generates a puzzle that needs Naked Triple and takes you straight to the position where it applies. Hints draw the pattern on the board and explain the step.
In a puzzle's rating
Each time the solver needs Naked Triple, the puzzle's difficulty rating grows by 80. Its class is Medium. It is needed in 1 in 10 puzzles that sudokUI generates. How the rating works.
More subsets
Naked Pair · Hidden Pair · Hidden Triple · Naked Quadruple · Hidden Quadruple