An example Center Dot puzzle: the nine box-centre cells (shaded) form an extra region that must hold 1–9.
Center Dot Sudoku marks the middle cell of each of the nine 3×3 boxes with a dot. Those nine dotted cells form an extra region that must contain the digits 1–9 exactly once, on top of the usual rows, columns and boxes.
The rule: the nine box centres hold 1–9
Take the centre cell of every box — there are nine of them, one per box — and treat them as a tenth unit: together they hold 1–9 with no repeats. The shaded cells below are those box centres.
The nine box-centre cells form an extra region that must hold 1–9.
How to use the centres
The nine centre cells sit neatly one per box and one per band and stack, so the extra region overlaps every box in exactly one cell. That makes the centre region a powerful long-range link: a digit in one box centre bans it from all eight others. Scan it like any unit, and lean on it whenever a digit is already crowded across the grid.
Solving strategy
- Treat the centres as a region. Hunt hidden singles among the nine dots as in a box.
- Exploit the one-per-box overlap. Each dot is its box's centre, so a digit placed there helps both units.
- Finish near-full dot regions. Eight known centres force the ninth.
- Feed the grid. Each centre digit placed behaves like a given for its row, column and box.
Common mistakes
- Forgetting the dots are a unit. The nine centres need 1–9, not just "no repeats with their boxes".
- Marking the wrong cells. Only the exact box-centre cells carry the rule.
- Scanning the region alone. Its strength is the overlap with every box.
- Dropping the ordinary rules. Rows, columns and boxes still apply on top.
Can I play it here?
Not yet — Center Dot Sudoku isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile:
- Browse all the Sudoku variants we do offer.
- Or print free puzzles from the printable PDF page.