Observatory Sudoku

Observatory Sudoku — calm sudoku in a night observatory: you solve sectors of the sky and stars light up above the dome.

Fair generator

Every puzzle is built on your device and has exactly one solution. Difficulty comes from the techniques it really needs, from singles up to X-Wing, XY-Wing and Swordfish — not from the number of empty cells.

Five difficulties

From Easy to Master: a puzzle is never handed out until it lands in its own class.

A hint that teaches

It does not just fill a digit in — it names the simplest technique that applies and highlights the cells. All 12 techniques are explained in the rules.

Comfortable input

Pencil notes with auto-clean, undo, auto-notes, highlighting of row, column, box and conflicts, three mistake modes.

Daily puzzle

A puzzle for every day and every difficulty, a month calendar and a streak counter.

Works offline, in Russian and English.