How to play Sudoku
Rules, modes, and shortcuts at a glance.
The rules
Fill every empty cell so that each row, each column, and each box contains every required digit exactly once. Morniura Sudoku supports 4×4 (2×2 boxes), 6×6 (2×3 boxes), and 9×9 (3×3 boxes) boards.
Two play modes
New Game
Choose a board size and difficulty (easy / normal / hard / expert) and the server generates a fresh, uniquely solvable puzzle.
Daily Sudoku
Everyone gets the same puzzle for the same UTC date and (board, difficulty) combination. Completed runs are recorded on the daily leaderboard.
Keyboard shortcuts
1–9: enter a number · Arrow keys: move · N: memo mode · H: hint · ⌘Z: undo · Space: pause · Backspace/Delete: clear
Scoring
Live score rises as you fill empty cells. On completion the server computes:
Final = (Live − Time penalty − Mistakes × 100) × Clean Run bonus
Live score
Empty cells × per-cell points. Per-cell value is set by difficulty and board size so every board carries a meaningful score range. Hint-filled cells count the same as any other.
| 4×4 | 6×6 | 9×9 | |
|---|---|---|---|
| Easy | 600 | 800 | 1000 |
| Normal | 900 | 1200 | 1500 |
| Hard | 1500 | 2000 | 2500 |
| Expert | 2400 | 3200 | 4000 |
Time penalty
Per second: easy 0.5 · normal 1 · hard 1.5 · expert 2 points. The total is capped at 50% of the live score, so a long game still keeps at least half.
Mistake penalty
Every wrong cell entry counts as one mistake and subtracts 100 points. Classic keeps wrong entries marked; Challenge shows them briefly after the server check, then clears them.
Clean Run bonus
Finish with zero mistakes and the final score is multiplied by ×1.2. Hint and memo usage do not affect the bonus.
Hints and score
Hints have no impact on the score. They are designed as a separate in-game item — earned through play or purchased — so the cost lives in the item economy rather than the score formula.
Fair play
Solutions never leave the server. Only the server verifies completion, and even failed submissions never return the correct values. Unusually fast completions are auto-flagged as suspicious and excluded from the ranking.