Sudoku: Daily Challenge

Sudoku the way it should be: every puzzle solvable by pure logic, every level unlocked from the start, and not a single advert anywhere. Most sudoku apps interrupt you. This one doesn't. There is no banner across the board, no video between puzzles, no "watch an ad for a hint", and no locked difficulty waiting behind a subscription. You open it, you play. PUZZLES THAT PLAY FAIR Every puzzle is generated with exactly one solution and checked to be solvable by human technique — you will never be forced into a guess. Choose Easy, Medium, Hard or Expert, and know that the label means something: puzzles are graded by the hardest technique they actually require. HINTS THAT TEACH YOU SOMETHING Stuck? A hint names the technique, shows you the cells it applies to, and explains the reasoning in plain English — "in box 1, 2 is confined to row cells A1 and A3, so 2 comes out of the rest of that row". Harder puzzles get multi-step hints you can page through, so you see how one deduction unlocks the next. LEARN FROM YOUR OWN GAMES The walkthrough replays a puzzle move by move: step back through what you played, then let the solver take over and narrate the rest. It is the fastest way to find out which technique you keep missing. PRACTICE EXACTLY WHAT YOU WANT Working on X-Wings? Build a custom puzzle from precisely the strategies you want to drill — naked and hidden subsets, pointing pairs, box/line reduction, X-Wing, XY-Wing, Swordfish, colouring, chains — and the generator guarantees a puzzle solvable with that set. PRINT PUZZLES FOR PAPER Prefer pencil and paper? Generate a PDF of up to 36 puzzles, six to an A4 page, in any paper size from A5 to A3 or US Letter and Legal. Print it, or share the file with someone who still does theirs at the kitchen table. Optionally print the list of techniques each puzzle needs. BUILT FOR SERIOUS SOLVERS • Pencil marks, plus optional row and column line notes for the digits you are tracking across a whole line • A two-row keypad so digits and pencil marks each get their own row — no toggling between modes • Undo, mistake counting with an optional strike limit, and a timer you can pause • Full history of past games with time, mistakes, hints and undos • Auto-check mistakes as you go, or turn it off and check on demand YOURS TO ADJUST Dark mode, larger text, and colour palettes tuned for protanopia, deuteranopia and tritanopia, plus a high-contrast board. Haptics and celebration animations can be turned off. PRIVATE AND OFFLINE No account. No sign-in. No ads. No internet connection required — puzzles are generated on your device, and your games never leave it.