Heidi's Infinite Sudoku

Sudoku for puzzle lovers. Billions of accurately rated puzzles, gentle hints, save files, colors, notes, touch, keyboard shortcuts.

NEW updated version for 2015: a new endless list of beautifully symmetric boards, a new highly readable handwriting font, and a bit more challenging levels. Heidi's Sudoku is different from other sudoku programs because it gives good hints. It can gently guide you out of a jam without giving away the whole puzzle. The Hint button highlights a few squares to concentrate on. Things are not totally given away, but if you hold down ctrl when clicking Hint, you will get more of an explicit hint. You can select Colors to see which parts of the board should be easiest to figure out first, and which parts are really hard and should be left to the end. Don't give up after you have hit a dead end in a puzzle. Use the Check button for a tip on whether you've made a mistake, and hold ctrl to see where it might be. More features: Switch between puzzles at your leisure. Learn to see tricks like naked pairs, hidden sets, xwing, ywing, swordfish, etc. Use mouse input or keyboard shortcuts. Tap with a tablet or touchscreen laptop. Pencil in notes, colors, or highlighting. Ratings grade actual difficulty. Save games or share with short urls. Track your speed with an optional timer. Enter and grade custom Sudoku puzzles. Heidi's Infinite Sudoku is inspired by Heidi and David's favorite way to play Sudoku: we love puzzling together and sharing really clever hints. This is a local HTML 5 app that works offline.