How to play Sudoku
Sudoku is a logic puzzle on a 9×9 grid divided into nine 3×3 blocks. Some squares already contain a digit. Fill in the empty squares so that every row, every column and every block contains the digits 1 to 9 exactly once. You never need to guess: each puzzle has exactly one solution.
The rules of Sudoku
- Tap an empty square, then tap a digit to fill it in.
- Every row contains the digits 1 to 9, each exactly once.
- Every column contains the digits 1 to 9, each exactly once.
- Every 3×3 block contains the digits 1 to 9, each exactly once.
- You never add anything up: the digits are only symbols, so no maths is needed.
Each puzzle has exactly one solution, so there is always a next step that follows from logic alone.
How to solve a Sudoku
Two simple techniques get you a long way. Use them one after the other until the grid is full.
Only one place
Pick a digit, say 7, and look at one block. Every 7 already in the grid rules out its whole row and column. Cross those squares off in your head. If only one empty square is left in the block, the 7 goes there.
Only one digit
Pick an empty square and look at its row, its column and its block together. Count which digits already appear there. If eight different digits are covered, the ninth is the answer for that square. In Vellara, the row, column and block light up as soon as you tap a square, which makes this easy to see.
Notes with the pencil
When a square could still hold two or three digits, write them small instead of guessing. As you fill in other squares, strike notes out. When one note is left in a square, that is your digit. In Vellara, switch the pencil on and tap a digit to write it as a small note.
Watch: how to play Sudoku
In under three minutes, this video goes through the rules, the two basic techniques (only one place and only one digit) and how to use notes with the pencil.
Playing Sudoku in Vellara
Tap a square and then a number. A wrong number turns red and counts as a slip. Every row, column and block contains the digits 1 to 9 exactly once. Sudoku comes in five levels, so you can start gently and move up when you are ready.
- Above the grid: smaller or larger numbers, fit to screen, a hint, and an info button that explains the rules.
- Below the grid: a pencil for notes, an eraser to clear a square and an undo button.
- No time pressure: a clock runs along, but you can take as long as you like.
- When the grid is complete, Vellara shows that it is solved and offers another puzzle or another level.
Questions about Sudoku
Is there only one solution to a sudoku?
Yes. Every sudoku in Vellara has exactly one solution, so you never need to guess. There is always a next step you can work out.
Do you need maths for sudoku?
No. The digits are only symbols and you never add them up. Sudoku is about logic and patience, not arithmetic.
What is the difference between easy and hard sudoku?
Easier puzzles can usually be solved with the two basic techniques on this page. Harder ones ask for more notes and more patience. Vellara has five levels, so you can step up gradually.
What happens if I enter a wrong number in Vellara?
The number turns red and counts as a slip. You can undo it or clear the square and try again.
Is Sudoku in Vellara free?
Yes. Vellara is free to download, needs no account and works offline.
Play Sudoku free in Vellara
Vellara is calm, free and works offline. It sends no notifications and puts no time pressure on you.
More puzzles in Vellara
If you like Sudoku, you may also like these:
- Killer sudoku
- Suguru
- Binary puzzle
- Star Battle
- Nonogram
- Logic puzzle