Sudoku Dark is a free, dark-themed Sudoku puzzle game you can play directly in your browser — no download required. Choose from Easy, Medium, Hard, and Expert difficulty levels, tackle a fresh daily challenge every day, and compete on global leaderboards. All puzzles, all features, completely free.
Sudoku is a logic puzzle played on a 9×9 grid divided into nine 3×3 boxes. The goal is simple: fill every empty cell so that each row, each column, and each 3×3 box contains the digits 1 through 9 with no repeats. No maths, no arithmetic — only logical deduction. Every puzzle has exactly one valid solution.
Getting started: Look for rows, columns, or boxes that are nearly complete — the missing digit becomes obvious. As the grid fills, use pencil marks (notes) to record which numbers are still possible in each cell. The two foundational beginner techniques are scanning (checking where a specific digit can go within a box) and crosshatching (eliminating positions using occupied rows and columns). Once you have the basics, our Sudoku strategy blog covers advanced techniques like Naked Pairs, X-Wings, and Swordfish.
Most Sudoku apps default to bright white backgrounds that cause eye strain during long play sessions, especially in low-light environments. Sudoku Dark was built from the ground up with a carefully tuned dark palette — deep navy background, high-contrast cyan highlights, and muted secondary tones — so the grid is always easy to read without visual fatigue. It is the same principle behind night mode on your phone, applied thoughtfully to every element of the puzzle interface.
Yes. All puzzles, difficulty levels, daily challenges, achievements, and leaderboards are free with no paywalls or premium tiers. The game is supported by optional ads.
No account is needed. You can play as a guest and your game state, stats, and achievements are all saved locally on your device. Creating an account (via Google or Apple) is optional and adds cross-device sync, leaderboards, and social features.
Yes. Sudoku Dark is a Progressive Web App (PWA). Once opened in your browser you can install it to your home screen and play without an internet connection at any time.
Each puzzle is algorithmically generated and verified to have exactly one valid solution. Difficulty is graded by the solving techniques required — Easy puzzles need only basic scanning, while Expert puzzles demand advanced logical deduction. No guessing is ever necessary.
Every day a new puzzle is published that is identical for all players worldwide. Your completion time is recorded and shown on the daily leaderboard. Solving the daily puzzle also counts toward your play streak.
There are 88 achievements covering milestones such as completing your first puzzle, hitting speed records, maintaining streaks, and mastering every difficulty level. Achievements are evaluated after each game and stored locally, with cloud backup available when signed in.
In guest mode all data stays on your device — nothing is transmitted to any server. If you sign in, only game-related data (scores, stats, achievements) is synced. We never sell your data. See our Privacy Policy for full details.
Yes. Sudoku Dark is available on the Google Play Store, the Apple App Store, and as a Progressive Web App in any modern browser. Your progress syncs across all platforms when signed in.
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