Fill the grid so that each digit appears just once in every row, column and box.
Three simple rules behind every puzzle.
Classic Sudoku uses a 9×9 grid, divided into 9 rows, 9 columns and 9 boxes of 3×3 cells. Your task is to fill the empty cells with digits from 1 to 9.
Each digit from 1 to 9 can appear only once.
The same rule works vertically — no repeats.
Each small box must also contain all digits from 1 to 9 without repeats.
Sounds simple — that’s the magic. Now let logic take over 🐾
Don’t guess — look for a cell with only one possible digit.
You don’t need to take in the whole grid at once. Pick a row, column or box and work out which digits are missing.
Then check the crossing rows and columns. If a digit has only one possible cell left, you’ve found your move.
Irbis suggests starting where plenty of digits are already filled in — fewer gaps mean fewer possibilities 🐾
Write down possible digits instead of keeping them all in your head.
If you’re not sure which digit belongs in a cell, use notes mode to add small candidate digits.
For example, if a cell could only be 2 or 7, note both. Once one of them appears in its row, column or box, you can remove that candidate.
Notes aren’t hints or cheating. They’re a perfectly normal tool for thinking.
Stuck? Irbis can help you find the next logical step.
A hint shouldn’t just throw a random correct digit at you. It first looks for a logical move you can make right now.
Each game comes with 3 base hints. If you run out, pet Irbis for one extra hint, once a day.
Try thinking it through for another moment — but if you’re really stuck, I’m right here 🐾
Start comfortably and build up to bigger challenges.
More starting digits and plenty of clear moves. A good way to get to know Sudoku.
Fewer obvious answers, so you’ll check candidates more often.
Think a few steps ahead and work carefully with notes.
For confident players who spot logical connections and want a real challenge.
There’s no rush to play harder puzzles. The best level is the one you enjoy thinking through.
Small habits that can get in the way of solving a puzzle.
Sudoku is a logic game. If two options seem equally possible, leave a note and come back later.
Always check the row, column and 3×3 box together.
On harder puzzles, notes make the next step much easier to find.
One wrong digit can muddle all the reasoning that follows.
Quick answers to the things new players often ask.
No. The digits in Sudoku are just symbols. What matters is logic, attention and spotting patterns.
You could try, but a well-made Sudoku can be solved logically. In IRBIS Sudoku, we encourage moves you can explain.
Try another box, row or column, update your notes, or ask Irbis for a hint.
It depends on the difficulty and your experience. An easy puzzle might take a few minutes; a hard one can take much longer. There’s no right pace.
Yes. Daily Sudoku gives you one new puzzle each day.
It’s one of the nine smaller squares within a classic 9×9 grid. Each box must also contain digits 1–9 without repeats.
A note is a candidate, not a final answer. A cell can hold several notes until you work out which digit belongs there.
Try Daily Sudoku — a fresh puzzle every day. Train your logic and follow your progress.
Daily Sudoku