What are the rules of Sudoku?
Sudoku is played on a 9×9 grid split into nine 3×3 boxes. Fill every empty cell so that each row, each column and each box contains the numbers 1 to 9 exactly once. No math is needed: the numbers are only symbols, and each puzzle has a single solution you can reach by logic alone.
In Marble Sudoku the numbers are nine marble colours, from Orange (1) to Sky (9), so you place marbles in holes instead of writing digits. The rules stay exactly the same, and you can show the numbers on the marbles at any time.
- 9×9 board
- Rows, columns and boxes
- One solution
The rules
- 1Rows. Each of the nine rows holds every number (colour) once.
- 2Columns. Each of the nine columns holds every number once.
- 3Boxes. Each of the nine 3×3 boxes holds every number once.
- 4Givens stay. The numbers printed at the start are fixed. You fill only the empty cells.
Watch it on the board
- Each row needs all nine colours once. This row is missing one, so it can only be that colour.
- Each column needs all nine too. One hole is left here, and only one colour fits.
- Each 3×3 box needs all nine as well. Eight are in, so the last hole is easy.
- Keep going until every hole is full. Then the whole board lights up.
Tips
- Start with the fullest lines. A row, column or box with only one or two gaps is the quickest place to find a move.
- Scan one number at a time. Pick a number and look at where it can still go in each box. Often only one cell is left.
- Use candidates when it gets hard. Write the possible numbers into each empty cell. Then the solving techniques show you which ones to remove.
- Never guess. A good puzzle always has a next logical step. If you are stuck, look for a single or a pair you missed.
Classic Sudoku and the other modes
| Classic | Mosaic (Jigsaw) | Rainbow Bridge (Thermo) | |
|---|---|---|---|
| Regions | Nine 3×3 boxes | Nine irregular shapes | Nine 3×3 boxes |
| Extra rule | None | None: shapes replace boxes | Numbers rise along each bridge |
| Good for | Learning and daily play | A fresh look at the same logic | Players who like extra clues |
Sudoku rules FAQ
What are the basic rules of Sudoku?
Fill the 9×9 grid so every row, every column and every 3×3 box contains the numbers 1 to 9 exactly once. The numbers given at the start cannot be changed.
Do you need math to play Sudoku?
No. The numbers are just nine different symbols. You never add them up. That is why Marble Sudoku can use nine colours instead.
Does every Sudoku have one solution?
A proper Sudoku has exactly one solution, and you can find it by logic without guessing. Every puzzle in Marble Sudoku is like that.
How do I start a Sudoku puzzle?
Look for a row, column or box with only one gap, or pick one number and check where it can go in each box. These are called singles.
What is the difference between easy and hard Sudoku?
Hard puzzles give fewer numbers at the start, and they need more advanced steps such as pairs, X-Wings or Y-Wings. The rules never change.
Is Classic one of several modes in Marble Sudoku?
Yes. Classic is the standard game. The other modes add a twist, such as boulders, fog, bridges, jigsaw shapes or a live race.
PLAY IT IN MARBLE SUDOKU
Play Classic Sudoku with marbles
Hand-crafted puzzles, soothing ASMR sounds and zen music. Place marbles instead of writing numbers.
Next modeJigsaw Sudoku
