Hyper Sudoku
A Sudoku variant with four extra 3×3 regions overlaid on the standard grid, each obeying the uniqueness rule. Also called Windoku in continental European communities.
Hyper Sudoku is a Sudoku variant played on the standard 9×9 grid with one structural addition: four extra 3×3 regions, called hyper regions, are overlaid on the grid, and each one carries the same digit-uniqueness rule as a row, column, or standard box. The puzzle is also known as Windoku, the original Dutch name from NRC Handelsblad where the variant was first published; the two names refer to the same puzzle.
Where the hyper regions sit
The four hyper regions occupy 3×3 blocks at fixed positions inside the grid: rows 2–4 columns 2–4, rows 2–4 columns 6–8, rows 6–8 columns 2–4, and rows 6–8 columns 6–8. The four regions don't touch each other and don't touch the grid edges. They're offset by exactly one cell from each corner of the board, which places them in the middle of each quadrant.
The total number of cells inside the four hyper regions is 36 — nine per region, four regions, no overlap. Each cell inside a hyper region belongs to four units (its row, its column, its standard 3×3 box, and its hyper region) instead of the three units a classic Sudoku cell has.
For details on the positions and the geometric reasoning behind them, see the four hyper regions.
How it plays
The technique vocabulary is unchanged from classic Sudoku. Every move — naked single, hidden single, pairs, triples, locked candidates, X-wing — fires the same way; the hyper regions just give the moves a fourth unit to fire on for cells inside one. The moves specific to the variant are the hyper-only cell, the hyper pair, and cross-region deduction — all variants of standard techniques on a hyper region.
For a full introduction with worked examples, see Meet Hyper Sudoku. For the practical scan-pattern habit, see when hyper regions narrow it down.
See also
- Windoku— An alternate name for Hyper Sudoku — the 9×9 Sudoku variant with four extra 3×3 regions overlaid on the grid. The original Dutch name from NRC Handelsblad.
- Hyper region— One of the four extra 3×3 regions in a Hyper Sudoku (Windoku). Each region carries the same digit-uniqueness rule as a row, column, or standard 3×3 box.
- Hyper-only cell— A Hyper Sudoku (Windoku) deduction: a cell where row, column, and standard box together leave multiple candidates, and the hyper region alone forces the digit.
- Hyper pair— A naked pair where both cells lie in the same hyper region of a Hyper Sudoku (Windoku). Eliminates the two pair digits from every other cell of that region.
- Cross-region deduction— A Hyper Sudoku move using the overlap between a hyper region and a standard 3×3 box: locking a digit to a shared sub-region eliminates it from the rest of both units.
- Unit— Collective name for a row, column, or 3×3 box — the three groupings Sudoku's no-repeats rule applies to. Every cell sits in exactly three: its row, column, and box.
Read more
- The rules of Hyper Sudoku
Hyper Sudoku — also known as Windoku — is classic Sudoku with four extra 3×3 regions overlaid on the grid. Each of the four hyper regions obeys the uniqueness rule.
- Meet Hyper Sudoku
An introduction to Hyper Sudoku (also called Windoku) — what the four hyper regions add, why classic solvers tend to enjoy it, and how to know if it's for you.
- The four hyper regions
Where the four extra 3×3 regions sit inside a Hyper Sudoku (Windoku) board, why they're positioned that way, and how to spot them while solving.