Sudoku HintHow it works
Consider the candidate numbers that could fit in an empty cell.
By excluding numbers already present in the same row, column, or block, only one possibility remains.
That number is then determined for the cell.
Example
1
2
3
4
5
6
7
8
9
Common mistakes
A lone note is reliable only if no candidates have been left out. Check the notes before confirming the number.
Practice · 2
Naked Single · Practice
Find a cell with just one candidate.
Two examples let you practise just one technique without solving a whole puzzle.