Sudoku Sutra

Play Sudoku Sutra

Levels

Easy, medium, hard and expert, graded by solving technique

Hints

3 per puzzle by default, each one explains its step

Daily

One puzzle a day, the same for every player

Saves

On your device after every move, no account needed

Developer

Classic Games

Works on

Phone, tablet and computer browsers. Nothing to install.

Released

October 2026

• Puzzle
• Number puzzle
• Logic
• Daily puzzle
• Brain game

Sudoku Sutra is classic sudoku, the number puzzle solved by logic alone, free to play in your browser with no download and no sign up. Fill the 9x9 grid so that every row, every column and every 3x3 box holds the digits 1 to 9 exactly once. Every puzzle is generated and checked by a solver to make sure it has exactly one solution, so there is always a single right answer to reason your way to.

Choose from four levels: easy, medium, hard and expert. Levels are graded by the hardest solving technique a puzzle needs, not only by how many digits are given, so each step up feels different. Pencil in notes, undo and redo without limit, and ask for a hint when you are stuck. A hint names the technique, lights up the cells involved and fills in one digit, so you learn the move instead of just copying an answer.

Each day brings one daily puzzle, the same for every player, and Sudoku Sutra keeps your daily streak and your best time for each level on your device. Mistakes never end a game: the Check button tells you how many digits are wrong without saying which ones. Your puzzle is saved after every move, so you can close the page and carry on later on the same device. Solve one, then send a friend a link to the very same puzzle.

How to play Sudoku

1. Choose a level from easy to expert, or play today's daily puzzle.
2. Tap or click an empty cell; the digits already given are your clues and cannot be changed.
3. Place a digit from 1 to 9 so that it does not repeat in that cell's row, column or 3x3 box.
4. Turn on Notes to pencil in the digits a cell could still hold, then narrow them down as the grid fills.
5. Use Undo, Erase, Check or a hint whenever you like, because a mistake never ends the game.
6. The puzzle is solved when every row, column and box holds each digit from 1 to 9 exactly once.

Controls

Click or tap a cell, then a digit on the number pad; the tools handle Undo, Redo, Erase, Notes, Hint and Check. With a keyboard, use the arrow keys to move, 1 to 9 to place, Backspace, Delete or 0 to erase, N for notes, H for a hint and Ctrl+Z or Cmd+Z to undo, with Shift to redo.

Hints that teach

A hint in Sudoku Sutra explains the next logical step instead of just handing you a digit. It names the technique, such as a hidden single, a pair or an X-Wing, highlights the cells involved and fills in that cell. If a digit you placed is wrong, the hint points that out first. You get three hints per puzzle by default, and Settings lets you choose 0, 1, 3, 5 or 9.

Levels graded by logic

Each puzzle is graded by a solver that works through it the way a person would, using five techniques from naked singles up to X-Wing. Easy puzzles need only the simplest steps, harder levels need more, and expert puzzles call for logic beyond those five. The number of given digits counts too, so hard really feels harder than medium, and every puzzle still has exactly one solution.

Easy to read and play

Selecting a cell highlights its row, column, box and every matching digit, and highlights never cover a digit. A Large digits setting and roomy notes keep the grid readable on small phones. Repeated digits are marked with a symbol as well as colour, and there is a high contrast theme, full keyboard play and screen reader labels for every cell.

Tips for solving Sudoku

• Start by scanning: pick one digit, see where it already sits in each row and column, and find the box where only one cell is left for it.
• Look for cells where eight different digits already appear in the same row, column or box, because only the ninth digit can go there.
• Once the quick placements run out, use Notes to pencil in every candidate, and keep 'Clear notes when I place a digit' switched on so they stay tidy.
• If two cells in the same row, column or box can each hold only the same two digits, those digits must go in those two cells. Cross them off the notes of every other cell there.
• Watch the number pad: it shows how many of each digit are left to place, and digits that are nearly finished are often the quickest to complete.
• Avoid guessing. Every puzzle has exactly one solution, so when you are stuck there is a logical step waiting, and a hint will name it.

Frequently asked questions