SepoGames › Sudoku

Sudoku — free online puzzles with one solution

Fill every row, every column and every three-by-three box with the numbers 1 to 9, using each number once. Every puzzle here is generated fresh and checked to have exactly one solution, so there is never any guessing — the answer can always be reasoned out. Four difficulty levels, from a gentle Easy up to Expert.

How to play

1. Tap an empty square, then tap a number on the pad below the grid.
2. Turn on Notes to write small pencil marks when more than one number could fit.
3. The number pad shows how many of each number are still missing.
4. Undo steps back through your moves, and hints fill in one correct square when you are stuck.

Tips

• Start by scanning for numbers that already appear seven or eight times — those are the easiest to place.
• If a row has only one empty square left, fill it immediately.
• Use pencil marks on Hard and Expert. Trying to hold the options in your head is what causes mistakes.
• A square with only one possible candidate is called a naked single — hunting for those solves most Easy and Medium puzzles.