Frequently Asked Questions

Sudoku is a logic-based number puzzle played on a 9x9 grid divided into nine 3x3 boxes. The goal is to fill every row, column, and box with the numbers 1 through 9, with no repetition. It requires no math — only logic and deduction.

Select an empty cell, then enter a number (1-9) that doesn't already appear in the same row, column, or 3x3 box. Use the Draft/Note mode to write possible candidates in cells. Continue until the entire grid is filled correctly. See our How to Play guide for detailed rules and tips.

Beginner puzzles have more given numbers and use only basic techniques. Intermediate adds moderate strategies. Hard and Expert require advanced techniques like X-Wing and XY-Wing. Choose the level that matches your skill and mood.

You get up to 10 hints per game. Each hint reveals the correct number for one cell. Hints are deducted from your score, so use them wisely. They're great for learning when you're stuck without spoiling the whole puzzle.

No. You can play Sudoku Battle immediately without signing up. Create an account only if you want to save your progress, sync across devices, and compete on the leaderboard.

Your current game is saved locally in your browser. For permanent saving and syncing across devices, sign in or create an account. Your progress will then be stored securely on our servers.

The leaderboard ranks players by score for each difficulty level. You must be signed in to appear on the leaderboard. Scores are based on correct moves, completion time, and hint usage. Compete to reach the top!

Use number keys 1-9 to enter numbers, arrow keys to move between cells, Ctrl+Z/⌘+Z to undo, Ctrl+Y/⌘+Y to redo, H for hint, D for draft mode, Space to pause, and Z for Zen mode. See the Shortcuts panel on the game page for the full list.

Zen mode hides the score, timer, and other UI elements so you can focus purely on the puzzle. It's perfect for relaxed, distraction-free solving. Press Z to toggle Zen mode.

When you play without an account, we store your game state locally in your browser. With an account, we store your email, username, game history, and scores to provide sync and leaderboard features. We do not sell your data. See our Privacy Policy for details.

Yes! Sudoku Battle is available as a mobile app for iOS and Android. Download it from the App Store or Google Play. The app offers the same features as the web version, with offline play and optional cloud sync.

For questions, feedback, or support, email us at hello@heyworkers.co. We typically respond within a few business days. You can also visit our Contact page for more information.