Difficulty you can trust
There are six levels, from Beginner to Fiendish. Each one is defined by the solving techniques it needs rather than by how many numbers are missing, so Easy puzzles can be solved by scanning alone, without pencil notes. Hard and above bring in pairs, pointing and X-Wings.
Hints that explain
A hint shows the next logical step and why it works, rather than just filling in a number. A short lesson introduces each new technique as you unlock it.
A daily puzzle
There is a new puzzle every day, the same for everyone. Keep a streak going, earn a streak freeze for busy days, and stamp each finished day in your calendar. A daily reminder is available if you want one.
Papers and pens
Every number you write is drawn stroke by stroke. As you level up you open stationery boxes and collect papers, pens, handwriting styles and stamps. Boxes are only ever earned, never sold.
Free, or support it once
Beginner to Hard are free, with an ad after some puzzles (never during one). A one-off Supporter purchase, with no subscription, adds Expert and Fiendish puzzles, removes ads, and gives unlimited hints, catch-up on missed daily puzzles and a "Fill notes" button.
Your progress stays on your phone and there is no account to make. See the privacy policy for how ads and purchases work.