Sudoku Unbound

Sudoku Unbound is classic Sudoku on a calm, legible grid, with hints that teach real logic and no ads, ever.

HINTS THAT REASON Ask for a hint and it comes in three steps. First it shows you where to look and names the technique. Then it explains the idea in one sentence. Only if you ask does it place the digit. A hint is always a deduction, never a guess. If you have made a mistake, the hint points to it first so you can fix it.

DIFFICULTY YOU CAN TRUST Each level is defined by the hardest technique the puzzle needs, not by how many digits are given. • Easy: singles only • Medium: pairs and box–line reduction • Hard: triples and X-Wing • Expert: Swordfish, XY-Wing and XYZ-Wing • Extreme: coloring and chains Nineteen techniques in all. Every puzzle has exactly one solution, checked by the solver before it ships.

PLENTY TO PLAY 1,500 puzzles across Classic 9×9 and Mini 6×6. Each new game reshuffles one of them (digits, rows, columns) so it plays fresh and keeps its level. Play as long as you like.

TOOLS THAT STAY OUT OF THE WAY • Notes, plus one tap to fill in every candidate • Notes clean themselves up when you place a digit (optional) • Unlimited undo and redo • No mistake limit; mistake marking is optional and off by default • Optional timer • Highlights for the row, column, box and matching digits • Your game saves itself and picks up where you left off

EVERY DAY The Daily Challenge: one Medium puzzle a day, free. Mini 6×6: short games in Easy and Medium.

SAME PROGRESS ON A NEW DEVICE No account to create. With iCloud sync on, your statistics, Daily history, settings and the game you are playing follow your Apple Account, so a new iPhone or iPad picks up where you left off. Pro comes back from the App Store.

GAME CENTER Optional leaderboards and achievements through Game Center: times for each level, for the Daily Challenge and for puzzles solved, plus 18 calm achievements with no streaks. Only grids solved without any help count for times: no hints, reveals, note checks or live mistake marking.

COMFORTABLE TO PLAY Light and dark appearance. Soft sounds and haptics, each one can be switched off. Supports Dynamic Type and Reduce Motion. Runs on iPhone and iPad. Playing needs no connection.

FREE AND PRO Free, with no time limit: Classic 9×9 Easy and Medium, Mini 6×6 Easy and Medium, the Daily Challenge, hints, notes and statistics. Pro is a single purchase that unlocks Hard, Expert and Extreme. Pay once, keep it for good, and restore it on any of your devices. Nobody sees ads, with or without Pro.

PRIVACY No account, no tracking, no ads. Your progress (statistics, games in progress, Daily Challenge and settings) follows your Apple Account through your own iCloud when sync is on. Nothing reaches us. Game Center, if you use it, is handled by Apple.

MORE WITH PRO Four Master Notebooks, advanced Technique Training, Master Challenge with its own archive, and authentic Diagonal, Killer, Samurai and Jigsaw variants. Included in the existing Pro purchase. The first notebook, basic exercises and a complete Hard sample are free.