VariantDoku vs Tsuidoku

No ads. No guessing. Just pure-logic variant sudoku. VariantDoku is built for solvers who want more than one daily grid — a growing library of 3,000+ variant and zero-givens puzzles, every one verified to have a single solution reachable by logic alone. No ads, ever — free or paid. WHY SOLVERS STAY - 3,000+ variant & zero-givens puzzles: killer cages, thermos, kropki dots, XV, arrows, renban, German whispers, palindromes, diagonals, anti-knight, and more - Every puzzle is logic-checked: one unique solution, no guessing required - A new daily puzzle, free for everyone — compare solve times on the daily leaderboard - Home-screen widget keeps today's puzzle one tap away - Audio narration reads the rules and tutorial steps aloud — listen while you study the grid LEARN ANY VARIANT - Step-by-step interactive tutorials for every variant, from your first 4x4 grid to mixed-constraint puzzles - A guided first-launch experience matches puzzles to your level — you're never thrown into the deep end - Already sharp? Skip straight to the expert grids TOOLS THAT RESPECT YOUR SOLVE - Candidate notes, corner marks, colors, and symbols for advanced solving - Error checking and gentle hints — only when you ask - Import puzzle links straight into your Library - Search and filters by difficulty, grid size, and constraint type - Streaks and solve history to track your progress - Dark mode and a calm interface designed for long sessions - Fully optimized for iPad in portrait and landscape, and runs on Mac BUILT TO BE ACCESSIBLE - VoiceOver plays the whole board: move cell by cell and hear the digit, your pencil marks, the clues on that cell and how it connects to its neighbours - Colour-blind support: German Whispers, Renban, Palindrome, Region Sum and Parity lines each have their own dash pattern, so no rule depends on colour alone - Reduce Motion is respected — staged hint reveals and animations settle immediately HINTS THAT COACH, NOT ANSWER - Every hint names the next logical step — Hidden Single, X-Wing, W-Wing, Simple Coloring, Forcing Chain — and highlights the cells it depends on - It reads the pencil marks you already made and builds on them - It never reveals a digit that isn't logically deduced; when the logic only rules candidates out, it shows you that instead of handing you a number THE VARIANTS LIST Classic Sudoku, Killer Sudoku, Kropki, XV, Thermo, German Whispers, Renban, Palindrome, Between Lines, Lockout Lines, Region Sum Lines, Arrow Sudoku, Diagonal (Sudoku X), Anti-Knight, Anti-King — plus multi-constraint puzzles that combine several on one board, and zero-givens puzzles solved entirely from the variant rules. Variant+ removes the hint limit and explains the available logical deductions step by step, and adds unlimited puzzles, unlimited error checking and offline Library play. The app stays 100% ad-free — free or paid. Whether you're learning your first killer cage or chasing your hundredth zero-givens solve, VariantDoku is a calm place to practice and improve. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Tsuidoku is a logic puzzle for players who have mastered classic Sudoku. The 9×9 grid remains, but a fourth constraint changes everything. THE 4 RULES Each row, column, and 3×3 region must contain the numbers 1 through 9 AND the 9 colors. The twist: each color must also contain all 9 numbers. The result: 81 unique number-color pairs. Place a "Red 5," and it cannot appear anywhere else. DAILY CHALLENGE A unique global grid every day—the same one for the whole world. Maintain your streak, earn monthly medals, and check the daily rankings. MASTER THE TECHNIQUES - Rainbow Technique: Track a single number across all nine colors. - Color Wheel: Track a single color across all nine numbers. Tap a cell to cycle through highlight modes and see the logic light up. PLAY TOGETHER Add friends, compare stats, and chat directly within the app. A detailed profile tracks your records across every difficulty level. Think you’ve mastered Sudoku? The real game starts here. Download now and create your first 81 perfect pairs.