Sudoku Ignite

A Sudoku game without annoying ads that teaches you how to play! Every hint names the technique and explains why it works, so you improve. Every hint names the technique it used and explains the reasoning in a sentence. It reads your own pencil marks, tells you when one of them rules out the right answer, and when a position genuinely cannot be settled by logic it says so instead of quietly handing you the answer. A built-in Techniques reference explains every strategy the guide can use, in the order it tries them, each with a worked example. LEARN TO SOLVE A campaign of 13 lessons takes the techniques in the order a solver meets them — singles, locking a symbol, pairs, then the patterns that reach across the grid — and teaches each one on the simplest board it applies to, finishing with a harder board to prove it stuck. NINE KINDS OF BOARD, 3,300 PUZZLES • 6×6 - the place to start. Same rules, less than half the squares. • 9×9 - classic sudoku in five difficulties, from easy to guru. • 16×16 and 25×25 - large grids with pinch-to-zoom, in five difficulties. • Jigsaw - nine irregular regions replace the boxes. • Killer - cages that add up to a total, with only a handful of starting digits. • Odd/Even - circled squares hold even numbers, so every square starts with about half its options ruled out. • Thermo - values rise along each thermometer, shown as a cool-to-warm gradient. • Samurai - five overlapping 9×9 grids on one board, in three difficulties. Every puzzle is distinct and has exactly one solution. On boards up to 16x16, difficulty is graded by the techniques a board actually needs, not by counting clues, and each tier is kept tight so two boards at the same level feel the same. DAILY, WEEKLY, ENDLESS • A Daily Challenge on any of the six small boards, Easy or Medium, the same for everyone that day. Build a streak, catch up from a 30-day archive, and turn on a reminder if you want one. • Share a picture of your result, with your time and streak. • A Weekly Challenge every Monday: one easy 16×16 or Samurai for everyone. • Endless 6×6 and 9×9, which build a fresh board every time you finish one. 135 ACHIEVEMENTS From your first clean solve to things only the obsessive will ever see. They are worked out from your own statistics, so everything you have already solved counts. PLAY YOUR WAY • Free input by default: enter what you think, then Undo, Redo or Erase. • Optional guided input that only accepts correct entries. • Optional mistake checking and a three-mistake limit. • Pencil marks that stay legible: up to four per square, drawn large, or automatic candidates for every empty square. • A color tool for following a chain by hand. • Number keys show how many of each number are still missing. STATISTICS Best and average times for every board type and difficulty, total solves, perfect solves, and your daily streak on a calendar. MADE TO BE READ A warm, calm design with light, dark and high-contrast themes, a reduce-motion option, and clear board markings for every variant: dashed cages, tinted overlaps, gradient thermometers. Works entirely offline. No account, no ads, no tracking.