SIZE GUIDE · 9×9
9×9 Sudoku complete guide
9×9 uses digits 1–9 and 3×3 boxes — the classic Sudoku board. Easy rounds take 5–10 minutes; Expert can exceed 20 minutes of focused solving.
Systematic solving order
With many blanks, guessing stalls quickly on 9×9. Apply named techniques in a fixed order and repeat until the board is complete.
- Pass 1: Naked Singles — fill every cell with one remaining candidate
- Pass 2: Hidden Singles — place digits that fit only one cell in a unit
- Pass 3: Locked Candidates — use box-line interactions to eliminate
- Pass 4: Naked / Hidden Pairs — break stalled sections with pair logic
Techniques by difficulty
Easy and Normal can be solved with Singles alone. Hard needs Locked Candidates, and Expert may require Pairs or beyond.
Ranking strategy
Guessing for speed costs mistake penalties and the ×1.2 clean-run bonus. Reliable technique application is more efficient for final score.
Practice order
- Full scanStart with rows, columns, and boxes that have the fewest blanks.
- Write candidatesAfter the scan, fill remaining blanks with candidate lists.
- Cycle techniquesApply Singles → Locked → Pairs in order to reduce candidates.
- RepeatEach placement opens new singles — loop back to pass 1.
Walk through a Hidden Single
Step 1 of 4
Focus on row 1. Pencil 9 as a candidate in every empty cell of that row.