How to Play Sudoku: Rules, Strategy & Free Puzzles

Sudoku is a logic puzzle played on a 9×9 grid divided into nine 3×3 boxes. The goal is to fill every cell with a digit from 1 to 9 so that each row, each column, and each 3×3 box contains all nine digits exactly once. No arithmetic is needed — only deduction.

• Skill: Logical deduction & pattern recognition
• ·
• Difficulty: Beginner to Advanced

How to play Sudoku

1. Read the givens. Each puzzle starts with some cells already filled. These clues are fixed and guarantee a single solution.
2. Fill rows, columns and boxes. Place digits 1–9 so every row, every column and every 3×3 box contains each digit exactly once.
3. Never repeat a digit. A digit may not appear twice in the same row, column or box. If it does, the solution is wrong.
4. Use elimination. For each empty cell, rule out digits already present in its row, column and box. When only one digit remains, place it.
5. Finish the grid. The puzzle is solved when every cell is filled and all three constraints hold with no conflicts.

Sudoku strategy & tips

• Scan for "naked singles" — cells where only one digit is possible.
• Look for "hidden singles" — a digit that can only legally go in one cell of a row, column or box.
• Pencil in candidate digits for tricky cells, then eliminate as you place others.
• Work the most-constrained areas first (boxes/rows that are nearly full).

Sudoku FAQ

Related puzzles

Reference: Sudoku on Wikipedia