Strategy

Sudoku tips and tricks

None of these tips needs talent. They are habits you can start using on your next puzzle.

Scanning

1. Scan one digit at a time. Find every place where, say, 4 must go.
2. Start with the digits that appear most often in the grid. They have the fewest places left.
3. Start with the fullest rows, columns and boxes.
4. Re-scan after every placement. New digits create new singles.

Notes

1. Write notes only when singles run out. Writing them too early wastes time on easy puzzles.
2. Write notes small and in the same positions in each cell (1 in the top left and so on). See how to use notes.
3. Update notes immediately after you place a digit.
4. Start your search for pairs with cells that have exactly two candidates.

Techniques

1. Learn techniques in order. See the techniques page.
2. Learn each technique on a real position, not just by reading about it.
3. Do not try a hard technique while an easier one still applies.
4. When stuck, check the box-line and pointing techniques before anything fancier.

Accuracy and mindset

1. Never guess. If you must, you are missing a technique.
2. If a cell has no candidates left, you made a mistake earlier. Undo until it is fixed.
3. Do not chase speed at the start. Accuracy first, then speed.
4. Take a break when you are stuck for 10 minutes. A fresh look often finds the move.
5. Move up a level when the current one feels routine.

The one tip behind all the others

Be systematic. Solvers who go through the same short list every time find more moves than solvers who wait for an idea. The full list is in how to solve Sudoku.