What is Factoku?

Factoku is an innovative number logic puzzle game. Unlike traditional Sudoku, players need to fill in numbers 2-9 in an 8×8 grid based on row and column product hints, with no duplicate numbers in each row and column. It's a game that combines mathematical reasoning and logical thinking.

How do I start playing?

Click the "Start Game" button on the homepage, select your desired difficulty level (Easy, Medium, Hard, Expert), then click on cells and fill in numbers based on the product hints shown at the top and left side of the grid.

What difficulty levels are available?

The game offers five difficulty levels: Easy (10 cells), Medium (15 cells), Hard (20 cells), Expert (30 cells), and Master (40 cells). Higher difficulties have more cells to fill and greater challenges.

What is Note Mode?

Note Mode allows you to mark possible candidate numbers in cells. This helps you record your reasoning process for later elimination. Click the "Note Mode" button to toggle this feature on or off.

What is Digit Composition Hint?

The Digit Composition Hint feature displays the factor decomposition of each row and column product, helping you understand which numbers might appear in that row or column. Click "Show Digit Composition" to view it, and "Hide Digit Composition" to hide it.

How do I print the game?

Click the "Print Game" button to print the current game as a physical version for offline play. The printed version includes the complete game grid, product hints, and a QR code share link.

How do I use Digit Composition Hints?

Click the "Digit Composition Hint" button to display the factor decomposition of each row and column product (e.g., 72 = 2³ × 3²), helping you analyze which numbers might appear in that row or column. Can be toggled on/off anytime with no usage limit.

Why did my number turn red?

Red numbers indicate rule violations. The game automatically checks: 1) Numbers must be unique within rows and columns; 2) Numbers must be factors of the row/column product. When you make a mistake, it briefly flashes red, but you can try unlimited times until you find the correct answer.

How do I undo an action?

Click the "Undo" button to undo your most recent number entry. If you want to clear the number in the currently selected cell, click the "Erase" button.

Does the game auto-save my progress?

Yes! The game automatically saves your progress to browser local storage. Even if you close the page, you can continue your previous game next time you open it. Note: Clearing browser data will delete saved progress.

What is the seed system?

The seed system allows you to reproduce the same game using a specific seed code. You can share the seed code with friends to challenge them with the same puzzle. Seed format: version-seed number-difficulty, for example 1-1234567890-15 (current version is v1).

How do I share a game?

After completing a game, click the "Share Challenge" button to copy a link containing the seed code to share with friends. When friends open it through the link, they can play the exact same puzzle as you.

What languages does the game support?

The game currently supports 8 languages: Chinese, English, Japanese, French, German, Russian, Spanish, and Portuguese. You can switch languages in the top right corner of the page.

Is the game free?

Yes, Factoku is completely free, requires no registration, and has no in-app purchases. We're committed to providing a pure gaming experience.

Does the game require an internet connection?

No. After the initial load, the game can be played completely offline. All data is saved locally in your browser and won't be uploaded to servers.

Why do some cells have numbers while others are empty?

Pre-filled numbers are initial hints provided by the game. These numbers are fixed and cannot be modified. Cells (marked with "?") are positions you need to fill.

How can I tell if a filled number is correct?

The game validates your answers in real-time. If a number is correct, it will remain in normal color; if incorrect, it will immediately turn red. You also need to ensure the filled number satisfies the row and column product requirements.

What should I do if I'm stuck?

If you encounter difficulties, try: 1) Use Note Mode to record possible numbers; 2) Use the Hint feature to get one correct answer; 3) Use Undo to rethink your moves; 4) If you really can't continue, you can start a new game.

How do I report a bug?

If you discover any issues or have suggestions for improvement, please contact us at [email protected]. We take every piece of feedback seriously.

FAQ