KOEN

Sudoku Online

PUZZLE · SUDOKU

Play freshly generated sudoku with exactly one solution in Easy, Medium or Hard, with pencil notes, mistake highlighting, number highlighting, undo and hints.

TIME0:00 MISTAKES0 HINTS0

HOW TO

How to use

  1. Choose Easy, Medium or Hard. A new puzzle with a single solution is generated.
  2. Click a cell, then press 1–9 or use the number pad below the board.
  3. Turn on Notes (N) to pencil in candidate numbers. Shift + number also adds a note.
  4. Use Undo (Z) or Hint (H) when stuck. Fill every cell correctly to finish.
PAIRS WELL WITH

Pairs well with

FAQ

FAQ

Does every puzzle have only one solution?

Yes. Each puzzle is checked to have exactly one solution, so you can solve it with pure logic and no guessing.

Is my game saved if I close the page?

Your puzzle in progress, options and best times are saved in this browser and restored when you come back.

Can I turn off mistake highlighting?

Yes. Switch off Highlight mistakes in red in the options. Wrong numbers then stay unmarked until the board is full.