Str8ts Solver vs VariantDoku

Jeff Widderich had the idea for Str8ts in 2008. Together with Andrew Stuart, he developed a new puzzle that is a successful successor to Sudoku. It is a puzzle where you have to enter the numbers 1 to 9 in the fields, where each digit may occur only once per line and column. With the app you can daily download new puzzles and solve them for free. There are puzzles in different difficulty levels, so that everyone will find something for their level of knowledge. If you can not find a solution, the integrated solver helps to find the next steps. The integrated solver is able to solve even the most extreme str8ts puzzles with a backtracking algorithm. So far, we've only found two puzzles where the one-step backtracking algorithm did not find a solution and needed support from the user. As a further function, you can even enter puzzles, which are available for example in printed form, by hand. An import via a text format is also possible. We thank Jeff Widderich and Andrew Stuart, who gave us permission to use the name "Str8ts". A highlight, of course, is the link from Andrew, through which he daily provides us with new puzzles for the app.

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/