Sudoku variant
Hyper Sudoku
Also called Windoku. Classic 9×9 with four extra 3×3 regions overlaid — each one carries the digits 1 through 9.
How Hyper Sudoku differs from Classic
Hyper Sudoku — also called Windoku — plays exactly like Classic Sudoku. Same 9×9 grid, same digits 1–9, same row, column, and 3×3 box uniqueness. The addition is four extra 3×3 regions, one inset from each corner of the board, each carrying the same uniqueness constraint as the standard boxes.
On the board the hyper regions are marked with solid coral outlines so they're clear at a glance. The four regions span rows 2–4 and 6–8 and columns 2–4 and 6–8 respectively (zero-indexed), which means each hyper region straddles parts of two standard boxes. That overlap is the source of the variant's extra deductive surface.
The trick of the variant is exactly that overlap. A digit blocked from one half of a hyper region by a row or column hit is forced into the other half — even when the standard box scan didn't make that obvious. When a puzzle feels stuck on standard scanning, the hyper regions are usually where the next deduction lives.
Tier calibration runs five givens tighter than Classic at each level — Easy 33, Medium 31, Hard 26, Expert 21. The four extra regions add more constraint than two diagonals do, so the same logical depth is reachable from fewer givens. Every puzzle is uniqueness-gated against the full hyper rule set.
Quick rules
- Every row contains each digit 1–9 exactly once.
- Every column contains each digit 1–9 exactly once.
- Every 3×3 box contains each digit 1–9 exactly once.
- Each of the four hyper regions (inset from each corner) contains each digit 1–9 exactly once.
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.
When hyper regions narrow it down
A practical tactic for Hyper Sudoku and Windoku: scan the hyper region as a fourth unit when row, column, and box reasoning runs out. Worked patterns and where they fire.
How Hyper Sudoku differs from classic
For solvers who already play classic Sudoku — what changes mentally when you switch to Hyper Sudoku (Windoku), and what carries over unchanged.
A short history of Windoku
Where Windoku (the original Dutch name for Hyper Sudoku) came from, how it spread, and why it's quietly maintained a thirty-year following in puzzle publishing.
Hyper Sudoku for beginners
Your first Hyper Sudoku puzzle, walked through end to end. Also known as Windoku — what to scan for, when the hyper regions help, and when you're ready for medium.