How to play Sudoku

The goal

Fill every empty cell in a 9×9 grid with a digit from 1 to 9, so that:

• Each row contains 1–9 with no repeats.
• Each column contains 1–9 with no repeats.
• Each 3×3 box contains 1–9 with no repeats.

That's it. The whole puzzle is just those three rules applied at once.

You never need to guess

A real Sudoku has exactly one solution, and that solution can be found purely by logic. If you find yourself guessing, you've probably missed a deduction. Slow down, look again, and consider the two techniques below.

Technique 1 — Naked Single

Look at one empty cell and ask: "Which digits would conflict with this cell's row, column or box?" If only one digit is left over, write it in.

Technique 2 — Hidden Single

Pick a digit, say 5. Look at one box. If 5 can only go in one cell of that box — even if that cell has other candidates — then it must be 5.

You can solve an easy Sudoku using just these two ideas. Read the Hidden Single page when you're ready for more detail.

Your first solve — a five-move walkthrough

Once the rules and the two techniques above are internalised, most players can solve an Easy board in under three minutes. The shape of every solve looks roughly like this:

1. Look at the givens. Sit for ten seconds and just see the board. Which digits appear the most? A digit that already appears seven or eight times is one hidden-single scan away from being fully placed.
2. Scan the most-used digit. Pick a digit that appears often in the givens — say 7. Look at each 3×3 box in turn: is there a box where 7 has only one legal home? Place it. Repeat across the grid.
3. Rotate through the other digits. Once you've done a full Hidden Single sweep for one digit, move to the next. Order doesn't matter — most Easy boards fall in two or three sweeps.
4. Fill Naked Singles as they appear. Any cell that has only one candidate digit left (based on its row, column and box) can be filled immediately. Cell-by-cell scanning is slower than digit-by-digit scanning, but does the last-mile work.
5. Verify. The moment the board is full, check each row, column and box once for repeats. On a well-formed board with a unique solution, if you never guessed, you can't be wrong — but the muscle memory of checking is worth building.

Common beginner mistakes (and how to avoid them)

• Guessing when you feel stuck. Random guesses are hard to recover from. Slow down, verify your candidates and try a structured technique before using search.
• Placing a digit "because it fits here." Half of it fitting isn't enough — a placement is only justified when no other cell in its row, column and box can hold that digit. If you can't articulate why you placed it, don't place it.
• Skipping the mental sweep. New players often place the obvious cells and then drift into staring. A structured digit-by-digit sweep beats staring every time — usually by an order of magnitude.
• Starting on Hard. Skipping Easy feels efficient but wastes a week. Easy boards are where Hidden Single scans become automatic; without that, Hard is unplayable.

How long should it take?

Rough sanity check for a beginner:

• First-ever Easy: 8–15 minutes. That's normal.
• Fifth Easy: 4–6 minutes. Hidden Singles are becoming visible.
• Twentieth Easy: 2–3 minutes. Time to try Medium.

If you're still taking 15 minutes on your tenth Easy, you're probably not doing a structured sweep. Read the two-technique section above once more and try to name the technique for every cell you place.

Where to go next

• Read the 10 essential tips for absolute beginners — the ones that turn a 15-minute solve into a 3-minute one.
• Study the 5 named beginner strategies that solve every Easy puzzle.
• Read the 10 essential tips for absolute beginners — the ones that turn a 15-minute solve into a 3-minute one.
• Study the 5 named beginner strategies that solve every Easy puzzle.
• Play today's Easy Sudoku to practice — the daily board rotates at midnight UTC.
• Read the full Sudoku rules for variants (4×4, 6×6, Killer) and edge cases.
• Browse the techniques library — Hidden Single, Naked Pair, Pointing Pair, X-Wing.
• Try a beginner's Sudoku walkthrough with worked examples.
• Prefer paper? Grab a free easy printable PDF pack.