SIZE GUIDE · 6×6
6×6 Sudoku complete guide
6×6 uses digits 1–6 and 2×3 rectangular boxes. Each round takes 3–8 minutes — enough room to practice real techniques without the commitment of a full 9×9.
The 2×3 box shape
Unlike the square boxes of 4×4 and 9×9, 6×6 boxes are 2 rows by 3 columns. This asymmetry creates more cross-checking opportunities and introduces the feel of Locked Candidates early.
Start using notes
On 4×4 you can hold candidates in your head, but 6×6 often leaves 3–4 candidates per cell on Normal or harder. Turn on note mode and write them down.
- For each blank, eliminate digits already in its row, column, and box.
- Focus on cells with only two candidates — resolving one triggers a chain.
- If a candidate in a box is confined to one row, remove it from that row outside the box.
When to move to 9×9
If you can finish 6×6 Normal in under five minutes and use notes naturally, you are ready for 9×9 Easy.
Practice order
- Enable notesPress N or tap the memo button to switch to candidate mode.
- Reduce candidatesWrite possible digits in each blank and cross off impossibles.
- Check 2×3 boxesWhen candidates line up inside one box row, apply Locked Candidates.
- Chain solvesEach placement narrows nearby candidates — look for cascades.
Walk through a 6×6 solve
Step 1 of 4
A nearly complete 6×6. Only row 1, column 1 is empty. Combining the row, column, and 2×3 box rules narrows the answer quickly.