How to solve Mini Sudoku

01 · Mini Sudoku

Start by scanning

Pick a digit, say 1, and look at where it already appears. Each 1 rules out its row, its column and its box for the other 1s. If that leaves only one empty cell in some box, row or column, the 1 goes there. Then do the same for 2, 3 and so on.

On a 6×6 grid a full scan takes seconds, and on an easy day it can solve most of the puzzle on its own.

02 · Mini Sudoku

Naked and hidden singles

Scanning finds hidden singles: a digit that has only one possible home in a row, column or box. The other kind is a naked single: a cell where five of the six digits are already used by its row, column and box, so only one digit is left for it.

• Look for naked singles in crowded areas, where a row and a column both have several givens.
• Look for hidden singles in boxes, which are small enough to check at a glance.
• Every digit you place can create new singles nearby, so look around the cell you just filled.

03 · Mini Sudoku

Use notes for pairs

When scanning stalls, write candidates into the cells as notes. If two cells in the same row hold only the same two candidates, say 2 and 5, those two digits must go in those two cells, so you can remove 2 and 5 from every other cell in the row. This is a naked pair, and it is usually all a Mini Sudoku needs.

Keep notes small and tidy. Once you place a digit, clear it from the notes in its row, column and box right away, or stale notes will mislead you later.

04 · Mini Sudoku

Moving up to full Sudoku

Everything here works the same way on the 9×9 grid; there are simply more cells to scan. If you can finish Mini Sudoku without guessing, try the full Sudoku next and use the same order: scan, singles, then notes.