Mini Sudoku 6×6 vs Sudoku 9×9 — how to choose
Grid sizes, box shapes, difficulty labels, session length, and touch size side by side, with a clear rule for picking one.
NoCharge publishes two Sudoku sizes. They share pencil marks, check/reveal tools, and a no-account, local-storage model — but they are different puzzles for different sessions.
The table
| Mini Sudoku 6×6 | Sudoku 9×9 | |
|---|---|---|
| Grid | 6×6, 3×2 boxes | 9×9, 3×3 boxes |
| Digits | 1–6 | 1–9 |
| Difficulty labels | Easy 12 / Medium 16 / Hard 20 removed | Easy 42 / Medium 34 / Hard 28 given |
| Typical session | 5–20 min | 8–25 min |
| Pencil marks | 6 candidates per empty cell | 9 candidates per empty cell |
| Current-puzzle resume | nocharge:sudoku:current-puzzle |
nocharge:sudoku9:current-puzzle |
| Solved count | nocharge:sudoku:puzzles-solved |
nocharge:sudoku9:puzzles-solved |
| Touch size | larger cells, one-thumb friendly | denser, needs more precision |
How the rule sets differ
Both require each digit once per row, column, and box. The 6×6 box shape is 3 columns × 2 rows; the 9×9 box is 3×3. The 6×6 therefore has six boxes and 36 cells; the 9×9 has nine boxes and 81 cells.
Which to pick
- One-thumb or a short break: 6×6. Its cells are roughly twice the area on a phone.
- A full sitting with cross-box reasoning: 9×9. Longer chains and hidden singles appear more often, though NoCharge does not claim one size is “smarter”.
- Learning the tools: start with 6×6; the Marks, Check, and Reveal controls work identically, and the shared pencil-marks preference carries over.
What NoCharge is not claiming
Difficulty labels are given counts (or removed counts), not grades. NoCharge does not state that either size trains anything, and both games are untimed. The session ranges are estimates from typical play, not limits.
Next step
Open Mini Sudoku 6×6 for a short session or Sudoku 9×9 for a longer one. Both are keyboard-complete and run without an account.