- Row 2: the highlighted cells can hold only 5 and 7.
- Each of 5 and 7 must take one of these cells.
- Row 2: so 5 and 7 can go nowhere else.
Naked Pair in sudoku
A Naked Pair is two cells of one row, column or box whose notes are the same two numbers and nothing else. The two numbers will fill those two cells, in one order or the other, so they can be removed from the notes of every other cell of that row, column or box.
Or scan with your phone
How to spot it
Look for cells with exactly two notes. When two of them in one row, column or box show the same two numbers, you have a pair. If the two cells share both a box and a line, the removal works in both.
Why it works
Two cells and two numbers: whichever cell takes the first number, the other takes the second. Both numbers are used up inside the pair, so no other cell of the unit can hold either.
On a real puzzle
This is Naked Pair on its practice puzzle, at the first step that needs it. The game's hint explains the step like this:
Practice it
This Master puzzle calls for Naked Pair. Fill in the singles first. When no number is obvious any more, look for the pattern, or ask for the hint: each game has one.