What Is Sudoku? A Beginner's Guide
One rule. Nine numbers. Millions of players. Everything you need to know to start solving today — explained in plain English.
The One Rule
Every row, every column, and every 3×3 box must contain the numbers 1 through 9 exactly once.
No arithmetic. No addition. No multiplication. Only logic. Every technique you will ever learn is just a clever way of applying this one sentence.
How to Play
No strategy required — just the rule and a little patience.
Look at the grid
Find a row, column, or box where only a few numbers are missing. Those are your easiest wins.
Ask: what can go here?
Check the row, column, and box of an empty cell. Cross off any number already used in those three units.
Place the number
When a cell has only one legal option left, fill it in. That is the sudoku feeling — and it is addictive.
Repeat
Every placed number removes options from other cells. The puzzle opens up step by step until the grid is full.
Why “Sudoku”?
From Japanese sū (number) + doku (single). Popularized in Japan in the 1980s, though its ancestor — called Number Place — first appeared in an American puzzle magazine in the late 1970s.
Pick Your Level
Same rule, different challenge. Start easy and work your way up.
Easy & Medium
Plenty of given numbers — most cells resolve with a single look.
Hard & Evil
Fewer clues. You’ll need pencil notes and multi-step logic.
Kids 4×4 & 6×6
Smaller grids for young players — same logic, less overwhelm.
Mega 16×16
A giant grid with 4×4 boxes — a serious workout for experienced solvers.
Common Questions
Is sudoku math?
No. It uses numbers as symbols — you could swap them for letters or shapes and the puzzle would work exactly the same. There is zero calculation involved.
Do I need to guess?
On a well-made puzzle, never. Every move can be found by logic alone. If you find yourself guessing, there is a technique you have not spotted yet.
Can I get better?
Yes — and faster than you think. Beginners improve fastest by learning a few core solving techniques and practising regularly. Our beginner’s guide walks you through your first finished puzzle step by step.
Ready to Start?
Reading about the rule is one thing — feeling it click is another. No sign-up, just the grid and the rule.