Playoku

HomeVariants › Hyper Sudoku (Windoku)

Hyper Sudoku (Windoku)

Play Hyper Sudoku, also called Windoku: classic rules plus four extra shaded 3×3 regions that must each contain 1–9.

Hyper Sudoku — also known as Windoku or NRC Sudoku — overlays four extra 3×3 regions on the classic grid, offset by one cell from the corners. Each of those shaded windows must also contain 1 to 9 exactly once.

Because the windows overlap the normal boxes, cells inside them gain powerful extra eliminations. Hyper rewards solvers who keep an eye on the overlay as well as the standard grid.

Rules

A sample Hyper Sudoku (Windoku) board — the highlighted cells show the variant's extra constraint.

Frequently asked questions

What is Hyper Sudoku?

Classic Sudoku plus four additional 3×3 regions, offset from the corners, that each must contain 1 to 9. It is also called Windoku.

Where are the extra regions?

They sit one cell in from each corner of the grid, overlapping the standard boxes — that overlap is what creates the extra deductions.

Want endless puzzles?

Classic Sudoku is ready to play right now, with four difficulties and three grid sizes. Explore more variants or sharpen up with the strategy guides.

Play Sudoku free →

How to play Sudoku on Playoku

Sudoku is a logic number puzzle played on a grid divided into boxes. Fill every empty cell so that each row, each column and each box contains every digit exactly once — 1 to 9 on the classic 9×9 grid, 1 to 4 on a 4×4 grid, and 1 to 6 on a 6×6 grid. Every puzzle on Playoku has exactly one solution and can be solved by logic alone, with no guessing required.

Features

Free to play, with no sign-up and no ads.

Frequently asked questions

Is Playoku free to play?

Yes. Playoku is completely free, with no sign-up and no ads. Just open the page and start solving.

How do you play Sudoku?

Fill every empty cell so that each row, each column and each box contains every digit exactly once. Every puzzle has exactly one solution and can be solved by logic alone.

What grid sizes and difficulties are available?

Playoku offers 4×4, 6×6 and 9×9 grids across four difficulty levels: Easy, Medium, Hard and Expert.

Can I share a Sudoku puzzle with a friend?

Yes. Use the Share button to copy a link that recreates the exact same board.