Sudoku strategies for beginners: from first move to finish

A practical beginner method for solving sudoku: cross-hatching, naked singles, and why you should never guess. Works on the easy and medium grids on this site.

Logic puzzles · Updated 2026-10-08

Sudoku looks like a maths puzzle and is not one. The digits 1 through 9 are symbols with no numerical meaning—you could replace them with nine colours and the puzzle would be identical. What you are actually doing is elimination: each row, column, and box must contain every symbol exactly once, and every placement you make narrows what can go everywhere else.

This guide covers the small set of techniques that carries you through the easy and medium grids on this site. None of them require guesswork.

Start with cross-hatching

Cross-hatching is the fastest way to make early placements, and it is the technique that makes the first half of a puzzle feel easy. Pick a digit and choose one 3×3 box that is missing it. Then look at the rows and columns crossing that box: any row or column that already contains your digit rules out every cell it passes through inside the box.

Usually two or three cells are ruled out immediately, and if only one cell remains, that digit must go there. Work digit by digit—1 through 9, then start again. Two passes of cross-hatching typically fill most of the obvious cells in a beginner grid.

The habit worth building is to scan a whole box before moving on, rather than hunting for one digit across the entire board. Your eyes find conflicts faster when the search area is small and consistent.

Candidate lists: write small, erase often

When a cell is not yet forced, note which digits could still legally go there. In a paper puzzle these are pencil marks; in our sudoku they are the note cells. Keep them short—usually three or four candidates per cell—and update them the moment a neighbour is filled in, because stale notes are the single most common source of apparent contradictions.

The payoff is what solvers call a naked single: a cell whose candidate list has shrunk to one digit. When you see one, place it immediately and then check what it unlocks nearby. A large share of a beginner puzzle is nothing but a chain of naked singles.

Hidden singles: the other easy win

A hidden single is the mirror case. A box might have four empty cells, all with three or four candidates each—but if only one of them can possibly hold a 7, then a 7 goes there regardless of what else could also fit. The digit has exactly one home, even though the cell has several occupants available.

To spot these, stop scanning cells and start scanning digits. Ask “where can 7 go in this box?” rather than “what goes in this cell?” That small flip in perspective is what separates a stuck beginner from a solver who keeps finding moves.

Why you should never guess

Guessing feels productive because it produces a move, but it converts a logic puzzle into a search tree. A wrong guess often stays invisible for twenty or thirty more placements, and when the contradiction finally appears you cannot tell which earlier choice caused it. You end up undoing everything and starting over—which takes longer than the patient route you avoided.

If you genuinely cannot find a next move, the honest conclusion is that you have not yet learned the technique the puzzle needs. On hard grids that might be a naked pair; on expert grids, a pointing pair or a box/line reduction. The puzzle is never asking you to gamble.

A working order for the whole puzzle

Cross-hatch each digit once across every box. Fill everything forced.
Build candidate lists for the remaining cells, keeping them accurate.
Sweep for naked singles and hidden singles, filling and updating as you go.
Look for pairs: two cells in a unit sharing exactly the same two candidates. Those two digits are locked into those two cells and can be removed from the rest of the unit.
Repeat. Most beginner and intermediate puzzles resolve completely in this loop.

Where to practise next

Start on easy sudoku and stay there until cross-hatching is automatic—that usually takes three or four puzzles. Then move to medium, where candidate lists start to matter. When medium grids consistently finish without guessing, hard introduces pairs and forces you to scan digits instead of cells.

When you want the theory behind the harder techniques, our advanced sudoku guide covers pointing pairs, naked pairs, and how to recognise them quickly. You can also play today's daily sudoku to compare your time against a fixed, shared grid.

Frequently asked questions

Do I need to be good at maths to play sudoku?

No. Sudoku uses only the digits 1 to 9 as symbols; no arithmetic appears anywhere in the game. It is a pattern and deduction puzzle, closer to a logic grid than to a sums puzzle.

Should I guess when I get stuck?

Almost never. Guessing turns a deduction puzzle into a trial-and-error exercise, and a wrong guess is usually only discovered many moves later. If you cannot find a logical next step, you have missed a technique rather than run out of luck.

What is the easiest way to start a sudoku puzzle?

Pick a digit, usually 1, and look at the three boxes that do not yet contain it. Cross-hatch the rows and columns that already hold that digit to see which cells are forced. Then repeat with 2, 3, and so on.

How long should an easy sudoku take?

For a beginner, an easy grid usually takes five to fifteen minutes. Speed comes from scanning technique rather than from thinking faster—most of the time saved is in noticing placements you would otherwise re-check.

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