How to Play Sudoku: A Beginner's Step-by-Step Guide

Sudoku looks intimidating — a 9×9 grid full of numbers — but it runs on a single rule and a little logic. This guide takes you from a blank grid to your first confident solve, with no jargon and no guessing.

The one rule of Sudoku

A Sudoku grid is 9 rows, 9 columns, and nine 3×3 boxes. Your job is to fill every cell with a digit from 1 to 9 so that each digit appears exactly once in every row, once in every column, and once in every 3×3 box. That's it — one rule, applied three ways.

The puzzle starts with some numbers already filled in (the "givens"). A proper Sudoku has exactly one solution, which means you never have to guess — every number can be worked out with logic.

Solve your first cell, step by step

1. 1

   Pick a busy box, row, or column

   Look for a 3×3 box, row, or column that already has lots of numbers. The more that's filled, the fewer possibilities remain — and the easier it is to place the next digit.

2. 2

   Choose a digit and ask 'where can it go?'

   Take a digit, say 5. Scan its row, column, and box. Every cell that already shares a row, column, or box with an existing 5 is ruled out.

3. 3

   Find the cell with only one option

   If a box has just one empty cell where the 5 is allowed, that's where the 5 goes. Write it in with confidence — this is a logical certainty, not a guess.

4. 4

   Repeat and let the grid open up

   Each number you place removes options elsewhere, which reveals the next placement. Keep rotating between boxes, rows, and columns.

The two techniques that solve most easy puzzles

You only need two ideas to finish nearly every easy Sudoku. They're two sides of the same coin:

Naked single

Look at a single empty cell. If eight of the digits 1–9 already appear in its row, column, or box, then only one digit is left — that digit must go in the cell. This is a naked single.

Hidden single

Now flip your thinking. Instead of looking at a cell, look at a digit inside one box and ask where it can go. If there's only one cell in that box where the digit is allowed, place it there — even if that cell could technically hold other numbers too. That's a hidden single.

When to use pencil marks

On easy puzzles, plain scanning is enough. When you move up to medium and hard, you'll start pencilling small candidate numbers into empty cells to track what's still possible. Don't do this too early on easy puzzles — it just adds clutter before you need it.

Do you need to be good at math to play Sudoku?

No. Sudoku uses digits, but no arithmetic — you never add, subtract, or multiply. It's a pure logic puzzle; the numbers could be any nine symbols.

Should beginners guess in Sudoku?

No. A well-made Sudoku has a single solution reachable by logic. If you feel the urge to guess, there's almost always a placement you've missed — recheck your rows, columns, and boxes.

What's the best way to get better at Sudoku?

Play easy puzzles until naked and hidden singles feel automatic, then move up a level. Consistent daily practice beats occasional long sessions.

That's everything you need to start. The best next step is to play — pick an easy grid and try to reach your first full solve using only the two techniques above.