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Fundamentals

Sudoku help: find a logical next move

A checklist for getting unstuck, one certain example move and the three stages of Unisu’s hints.

View the example grid
Unisu lesson on Full House, showing the explained grid

When no move stands out, start with a smaller question. Which digit is missing from a nearly full row? Which candidates remain valid after the last move?

Check the basics first

Look for a row, column or box with one gap, then check Naked Single and Hidden Single. Update notes in the areas affected by your last move. An incorrect entry or missing possibility can hide the next deduction.

One certain move

For a simple example, a row already contains 1, 2, 3, 4, 5, 6, 8 and 9. Only 7 is missing, so it belongs in the last empty cell: a Full House. With several gaps, also check the positions allowed by columns and boxes.

Read a hint in Unisu

A hint first points to the relevant area, then explains the reasoning and finally names the move. Open the stages in order and check the idea against the grid. All stages for the same move use only one of the three hints per puzzle. You enter numbers yourself and explicitly accept suggested candidate eliminations.

Keep learning from the move

After reading a hint, try spotting a similar pattern yourself. Each linked guide explains one principle. In the app you can follow guided examples and attempt independent tasks. This page is not a solver for arbitrary puzzles entered from elsewhere.

Frequently asked questions

What should I check before opening a hint?

Look at nearly full areas, check Singles and update affected notes. An incorrect entry can also hide a valid next move.

How many hints do I get per puzzle?

Three. The explanation stages of the same move count as one hint. You can reopen an explanation you have already viewed.

Does a hint enter the answer automatically?

You enter digits yourself. Candidate eliminations require your confirmation; reading the explanation does not apply the move for you.

Why does a hint sometimes only remove a candidate?

In harder puzzles, an elimination may be the next justified step. It can lead to a definite placement later.

Can I submit another puzzle to be solved here?

This website is not a solver for imported puzzles. The guides explain reasoning; the app’s hints work from its current game state.

Keep practicing in Unisu

Download Unisu for iPhone or Android. Solve a puzzle or work through a guided lesson on the technique.

Example grid

Unisu lesson on Full House, showing the explained grid

Useful before this guide

An explanation in stages
Start with the relevant area, then read the reasoning and the specific move. You still enter the number yourself.
Download app

Ready for a puzzle? Take a moment.

Download Unisu on your phone. Start a Sudoku or choose a lesson on the technique you want to understand.

The daily challenge in Unisu
A classic Sudoku game in Unisu