Sudoku is a logic puzzle: each row, column, and 3×3 box must contain 1–9 exactly once. The goal isn’t speed at first — it’s building a repeatable process so you don’t guess.
What Is Sudoku? (Quick Rules)
- Digits 1–9 appear once per row, column, and box.
- Given numbers are fixed; you fill the blanks.
- If a move causes duplicates in a unit, it’s a conflict.
The 3 Most Common Beginner Mistakes
- Guessing too early instead of narrowing candidates.
- Not using Notes (pencil marks) when a cell has multiple options.
- Ignoring structure — Sudoku is about units (row/column/box), not isolated cells.
Core Techniques
Scanning (Row/Column/Box)
Repeatedly scan units for what’s missing. When a row is missing only one number, that cell is forced.
Candidate Notes (Pencil Marks)
When a cell isn’t forced, write down its candidates. Notes turn “maybe” into something you can eliminate systematically.
Elimination Mindset (Don’t Guess)
Each placement should be justified by “this is the only possible number here” (a forced move), not by chance.
Intermediate Patterns (Optional)
- Naked singles: a cell has only one candidate.
- Hidden singles: within a unit, a number can go in only one place.
- Pairs/Triples: a small set of candidates locked into a small set of cells.
Advanced Strategy (Teaser)
X‑Wing (High level)
Some patterns work across multiple rows/columns at once. X‑Wing is one example: it eliminates candidates by finding a repeating constraint pattern.
Practice Plan (7 Days)
- Days 1–2: focus on scanning + singles only.
- Days 3–4: add Notes consistently.
- Days 5–7: review mistakes and try harder puzzles.
Try It Now
Use the in‑game Notes and Hint controls to learn faster, then challenge yourself with a Hard puzzle.