How to Play Sudoku Step by Step: Complete Beginner's Guide
By Michel ·
Standard Sudoku uses a 9×9 grid divided into nine 3×3 boxes. Fill the empty cells with digits 1–9 so each row, column and box contains each digit once. Keep the printed givens unchanged. The digits are labels; no arithmetic is needed.
1. Check a nearly complete unit
A row, column or box is a unit. If eight digits are filled, identify the missing digit and check the crossing units before placing it. For example, 1,2,3,4,5,6,7,8 leaves 9. If the empty cell’s column already contains 9, inspect earlier entries instead of creating a duplicate.
2. Scan one digit at a time
Choose a digit and inspect a unit where it is missing. Existing copies in crossing rows, columns and boxes rule out cells. If exactly one position remains in that unit, place the digit there: that is a hidden single. One digit having several possible positions does not justify choosing one.
3. Check a cell’s candidates
For an empty cell, exclude digits already in its row, column or box. If the combined exclusions are 1,2,3,4,5,6,7,8, only 9 remains: a naked single. If no candidate remains, there is an error in the entries or notes; that is not a valid placement example.
4. Use notes when they help
Candidate notes record remaining possibilities, not final answers. You can place an obvious forced digit without filling every cell with notes first. For more involved patterns, make the relevant notes complete and current. Remove a placed digit from its peers and check why each later elimination follows.
5. Repeat, or ask for an explanation
After a placement, recheck its row, column and box. If no move appears, inspect another unit and verify recent entries. The stuck guide suggests a next step. An answer key checks the result; a worked lesson explains the deduction.
Choose your first practice puzzle
Try the interactive beginner course, then an Easy puzzle or generated Easy printable pack. Paper and digital play are both valid choices. There is no required first-solve time or fixed number of puzzles before you move up.
Difficulty labels vary by publisher and are not determined by clue count alone. Use the difficulty guide to choose a comfortable challenge and the strategy library when you want another technique.