SudokuWorldTournament

Welcome to SudokuWorldTournament — a competitive Sudoku experience built on pure logic and respect for your privacy.

Downloading the app: Search for "SudokuWorldTournament" on the App Store, or tap the download link on this website. The app is free with no account required.

EULA and privacy consent: On first launch, you will be asked to accept the End User Licence Agreement and privacy consent. The app collects no personal information — you remain completely anonymous.

Choosing your first difficulty: After consent, select a difficulty level to begin. If you are new to Sudoku, start with Easy. You can change the difficulty at any time from the main menu.

Selecting a cell: Tap any empty cell on the board to select it. The selected cell is highlighted, along with its row, column, and box.

Placing a number: Use the number row (1–9) at the bottom of the screen to place a digit in the selected cell. If the number is correct, it stays. If input mode is set to reject wrong numbers, incorrect placements are blocked.

Understanding the score system: You earn points for every correct cell placement. The score depends on which solving technique the placement represents — harder techniques award more points. For example, a Naked Single earns fewer points than an X-Wing elimination.

Score HUD: Your current score is displayed at the top of the screen with an animated count-up effect whenever you earn points.

SudokuWorldTournament offers five difficulty levels, each requiring progressively more advanced solving techniques:

Easy: Primarily Naked Singles and Hidden Singles. More given cells, ideal for beginners.

Medium: Introduces Naked Pairs, Hidden Pairs, and Locked Candidates. Fewer given cells.

Hard: Requires techniques like Naked Triples, Hidden Triples, and Pointing Pairs.

Expert: Demands advanced strategies including X-Wing, Swordfish, XY-Wing, and Simple Colouring.

Professor: The ultimate challenge. Requires XYZ-Wing, Remote Pairs, and advanced chain techniques. Professor is locked by default — you must complete a 28-day Daily Challenge streak to unlock it.

The tool row sits below the number row and provides essential gameplay tools:

Erase: Removes the number from the currently selected cell. Only works on cells you have filled in (not given cells).

Notes (Manual/Auto): Tap to toggle note mode. In note mode, tapping a number adds or removes a pencil mark (candidate) in the selected cell. Long-press the Notes button to auto-fill all valid candidates across the entire board.

Notes Strategy: Toggle between two note behaviours — error marking (highlights conflicting notes in red) and auto-prune (automatically removes invalidated candidates when you place a number).

Hint: Tap to reveal the correct number for the selected cell, along with an explanation of the solving technique used. Long-press for the advanced solver, which shows a detailed step-by-step breakdown.

Undo: Reverts your last move. You can undo multiple times to step back through your history.

Autoplay: Activates the technique showcase mode. The app auto-solves the puzzle step by step, displaying each technique as it is applied. A brilliant learning tool.

Pause: Pauses the game timer. The board is hidden while paused to prevent unfair advantages.

Every day, a brand-new puzzle is generated and shared with all players worldwide. Everyone gets the exact same puzzle, making the Daily Challenge a true test of skill.

Daily leaderboard: Your completion time and score are ranked against all other players who completed the same puzzle that day.

Streak badges: Complete consecutive daily challenges to earn streak badges:

🔥 3+ days — Fire streak
⚡ 7+ days — Lightning streak
👑 28+ days — Crown streak (also unlocks Professor difficulty)

Notification reminders: Enable notifications to receive a daily reminder so you never break your streak.

Tribes are teams or groups that compete together. They are perfect for colleagues, friends, university groups, or sports clubs.

Creating a tribe: Premium users can create up to 8 tribes. Choose a name, set it as open or invite-only, and share the invite link.

Joining a tribe: Join via an invite link shared by a tribe member, or browse and discover open tribes in the app.

Open vs invite-only: Open tribes can be found and joined by anyone. Invite-only tribes require a direct link from an existing member.

Tribe leaderboards: Each tribe has its own leaderboard, filtered by difficulty level. See how you rank within your tribe across Easy, Medium, Hard, Expert, and Professor.

Sharing invite links: Tap the share button on your tribe page to copy or send the invite link via any messaging app.

SudokuWorldTournament features monthly tournaments with global rankings. Compete against players from around the world.

Difficulty-filtered leaderboards: Leaderboards are separated by difficulty level, so you compete against players tackling the same challenge.

How scores are submitted: Your score is automatically submitted when you complete a puzzle while online. If you are offline, scores sync when connectivity is restored.

Optimistic local display: Your score appears on the leaderboard immediately on your device, even before server confirmation. This ensures a seamless experience.

Base score: Every correct cell placement earns a base score. The exact amount depends on the solving technique identified for that move.

Technique-based scoring: Harder techniques earn more points. A Naked Single might earn 10 points, whilst an X-Wing elimination could earn 150+ points.

Time bonus: Each difficulty has a par time. Finishing faster than par earns a time bonus. The bonus decreases as you approach and exceed the par time.

Error and hint penalties: Each incorrect placement or hint used reduces your final score. Play carefully to maximise your total.

Perfect play kicker: Complete a puzzle with zero errors and zero hints to earn a perfect play kicker bonus — a significant score multiplier.

Bonus animation: After completing a puzzle, a celebratory animation displays your breakdown: base score, technique bonuses, time bonus, penalties, and the final total.

Premium: A one-time purchase that removes all advertisements permanently. No subscriptions, no recurring charges. Buy once, enjoy forever.

Gaming Credits: If you prefer not to purchase Premium, you can earn Gaming Credits by watching a short advert. Each advert watched earns 1 credit. Each game session costs 3 credits for an ad-free experience.

How it works: 1 advert = 1 credit. 3 credits = 1 ad-free game session.

Offline play: Playing offline requires either Premium status or sufficient Gaming Credits. This ensures the app can function without an internet connection.

Scan and Solve lets you capture or import a photograph of any Sudoku puzzle — from a newspaper, book, or magazine — and watch it solved step by step.

Capture or import: Use your device camera to photograph a puzzle, or import an image from your photo library.

Automatic grid detection: The app detects the Sudoku grid and recognises the printed digits using optical character recognition (OCR).

Manual correction editor: If the OCR misreads any digits, a correction editor lets you fix them before solving.

Step-by-step animated solution: Once confirmed, the app solves the puzzle using real human techniques, displaying each step with technique labels (e.g., "Hidden Pair in Row 3").

Learning tool only: Scan and Solve is designed for learning and curiosity. No score is awarded for scanned puzzles.

Solving technique tutorials: In-app tutorials explain each solving technique with visual examples. Learn Naked Singles, Hidden Pairs, X-Wing, Swordfish, and many more.

Brain Age calculator: Based on your solving speed and accuracy, the app estimates your "brain age" — a fun metric to track your cognitive sharpness over time.

Weekly recap: Every week, receive a summary of your performance: puzzles completed, average time, techniques used, tribe rankings, and personal bests.

Awards and celebrations: Earn awards for milestones like completing your first puzzle, achieving a 7-day streak, or solving an Expert puzzle with zero errors. Celebratory animations mark each achievement.

Language selection: The app supports 30+ languages. Change the language at any time from Settings.

Board scale adjustment: Resize the Sudoku board to suit your screen and preference. Useful for larger devices or accessibility needs.

Score animations toggle: Enable or disable the animated score count-up and celebration effects.

Notification preferences: Control which notifications you receive — daily challenge reminders, streak warnings, tribe updates, and more.

Input mode (reject wrong numbers): When enabled, the app prevents you from placing an incorrect number. When disabled, wrong numbers are placed but flagged as errors.

Share a referral link to invite friends to download SudokuWorldTournament. This is separate from tribe invites — referral links encourage new players to join the community.

Tap the "Invite Friends" option in the app menu to generate and share your personal referral link via any messaging or social media app.

Anonymous play: No email, no account, no personal information required. You are identified only by an anonymous score ID.

GDPR compliance: The app is fully compliant with the General Data Protection Regulation. All data handling follows strict European privacy standards.

Data deletion: You can request deletion of all your data at any time from the Settings menu. This removes your scores, preferences, and any stored information.

Score sharing opt-out: If you prefer not to appear on leaderboards, you can opt out of score sharing in Settings. Your scores will still be tracked locally but will not be submitted to the server.