How to Play Sudoku: A Complete Guide for Beginners

发布于 2025-01-15 · 阅读约 6 分钟

Sudoku is one of the most popular logic puzzles in the world. It looks intimidating at first, but once you understand the three basic rules, you can start solving your first puzzle within minutes.

This guide walks you through everything a beginner needs to know — from what sudoku is, to how to make your very first move.

What is sudoku?

Sudoku is a number-placement puzzle. You are given a grid partially filled with digits, and your job is to fill in the empty cells so that every row, every column, and every box contains each digit exactly once.

The most common sudoku is a 9×9 grid divided into nine 3×3 boxes, using digits 1 through 9. There are also smaller variants: 4×4 for kids, 6×6 for beginners, and others.

The three basic rules

Every sudoku puzzle follows the same three rules, no matter the grid size:

1. Each row must contain every digit exactly once.
2. Each column must contain every digit exactly once.
3. Each box must contain every digit exactly once.

That's it. No math, no guessing — pure logic.

A simple 4×4 example

Let's start with a tiny 4×4 sudoku. Digits are 1–4, and the boxes are 2×2.

Look at the top-left box. It already contains 1 and 4. That means the two empty cells in this box must be 2 and 3.

Now look at the first column. It already has 1 and 4. So the remaining two cells must also be 2 and 3. But the top-left cell is in both the top-left box and the first column — both of which already have 1 and 4. So we know the top-left cell is either 2 or 3.

This kind of cross-referencing is how every sudoku is solved. You narrow down possibilities until only one digit fits.

Your first technique: the naked single

The easiest way to make progress is to look for cells where only one digit can possibly go. This is called a naked single.

Here's how to find one:

1. Pick an empty cell.
2. Look at its row, column, and box.
3. Cross out any digit that already appears in any of those three areas.
4. If only one digit remains, that's the answer.

Tip: In a 9×9 puzzle, scanning for naked singles is the fastest way to get started. Once you find a few, the puzzle starts to open up.

Common beginner mistakes

• Guessing. Every sudoku puzzle has exactly one solution and can be solved by logic alone. If you're guessing, you've missed something.
• Forgetting to check the box. Beginners often check the row and column but forget the 3×3 box.
• Starting with the hardest cells. Start with the most constrained cells — the ones with the fewest candidates.

Ready to start?

Now that you know the rules, try your first puzzle on our online sudoku. Start with a 4×4 or 6×6 printable puzzle if you want something easier, or jump straight to 9×9 when you feel ready.

Once you can solve easy puzzles comfortably, move on to our guide on basic sudoku strategies to learn how to solve medium puzzles.