Sudoku

01 / Goal & rules

1. Fill every cell without repeating a digit in any row, column or outlined box.
2. Easy uses 4×4 with 2×2 boxes; normal 6×6 with 2×3 boxes; hard 9×9 with 3×3 boxes. Original givens cannot change.
3. Notes hold candidates, not answers. Check conflict markers and finish every cell.

02 / Controls & guided practice

1. Select a cell, then a digit. Clear removes an entry; note mode records candidates.
2. Hints mark a run as assisted and reduce its score. The interactive lesson demonstrates notes, protected givens and completion.

Choose Learn by doing above to try coached moves on a real practice board. Your current game is preserved; tutorial results are never recorded.

03 / How scoring works

1. On completion: max(0, 100,000 − moves×40 − hints×12,000). An unfinished grid scores 0.

Time is informational and is not part of this score formula. Scores are derived from game state; different games use different scales.

04 / A thought for your next move

1. Begin with a row or box that has few empty cells.
2. Resolve single candidates, then cross-check where each missing digit can go.