how to play
- Click a cell to select it, then type or tap a digit.
- 4×4: digits 1–4, 2×2 boxes. 6×6: digits 1–6, 2×3 boxes.
- Classic: standard 9×9. Diagonal: both main diagonals must contain 1–9.
- Jail: 4 extra overlapping 3×3 windows (shaded purple) must also contain 1–9.
- Conflicts are highlighted in red. Given clues are fixed.
- Use notes mode to pencil in candidates.
click = select · type digit · N = notes mode · arrows = navigate