Stage 1 — Naked Single
The simplest move in sudoku: a cell with only one digit it can hold.
A naked single is a cell whose row, column, and 3×3 box have already used eight of the nine digits — leaving exactly one digit that can legally go there. Every sudoku starts with at least one of these, and most easy puzzles solve almost entirely from naked singles. Spotting them is the foundation of every other technique you'll learn.
Read the technique guide →Practice
Puzzle 1 of 3Finding a puzzle that uses this technique…