Sudoku meets crosswords

Fill each run of white squares with digits from 1 to 9 so the total matches its clue. A digit cannot repeat within a run, and every square crosses another clue. The rules are simple; the deductions can keep unfolding for as long as you want to play.

A puzzle for every kind of break

2,000+ free puzzles across six board sizes, from a quick 3×3 Mini to a sprawling 30×30 Colossal.
A fresh daily challenge every morning, with streaks and daily puzzles separate from the main library.
Smart help without spoilers, including combination lists, remaining sums, color-coded pencilmarks, and hints that explain the next deduction without making the move for you.
Play anywhere with full offline support, no account, and no sign-up required.
Handwriting with a stylus or a finger, learned privately and processed entirely on the device.
Comfortable controls with light and dark modes, a newspaper-style board, flexible zooming, adjustable error checking, and virtually unlimited undo and redo.

Designed for logic, not guessing

Every included grid is checked to have exactly one solution that can be reached through logic alone. Start with the gentle teaching ramp, build confidence with smaller boards, and move into larger puzzles when you are ready for a longer solve.

Quiet by design

No ad ever appears while a puzzle is open. Limited ads elsewhere help keep the full puzzle library free, and one optional purchase removes them permanently. There is no subscription.