Sudoku Made and maintained by Brian Hamilton and Karan Hamilton.
Brian builds the playable puzzle tools, while Karan helps test clarity, difficulty feel, and the player experience.
Playable puzzles and controls are tested in the browser for rule accuracy, usability, and a clear solving experience. See how we make and test puzzles, our editorial standards, or report a problem.
Space Sudoku: Rockets, Planets, and One Hard-to-Find Alien
Space Sudoku plays classic Sudoku with nine tiles from the night sky — rocket, planet, star, moon, sun, comet, alien, telescope, and galaxy. Fly it with pictures, with digits, or with both instruments on; the logic underneath never changes: each tile once in every row, column, and box.
You have to earn the alien
The starter 4x4 board keeps to things you could point at from a back garden — the rocket, planet, star, and moon. The sun and comet join at 6x6, and the alien, telescope, and galaxy only turn up on the full 9x9. That is a side effect of how smaller boards take the first tiles in the set, but we like the accidental story it tells: you need the biggest board, and the telescope that comes with it, to find the alien.
Nine lights in the dark
The tricky corner of this tile set is that space is full of things that shine. The star, the sun, and the comet are all bright, radiating shapes, and they are the three most often confused at phone size; the moon and the planet can read as cousins too. The rocket, alien, and telescope hold the set together because nothing else on the board looks anything like them. Before starting a hard 9x9, it is worth switching the display to Both — a star mistaken for a comet can quietly wreck ten minutes of careful work, and the small number badges make that mistake impossible.
A theme that isn't waiting for a holiday
Most of our picture boards belong to a season. Space belongs to whoever is currently obsessed with it, which in our experience is always somebody. It fits naturally into a school space topic week, and one honest note for teachers and parents who ask: this game will not teach the order of the planets or what a comet is made of. It teaches scanning, elimination, and giving a reason for a decision. The space tiles are the hook, not the lesson — and that is fine, because the hook works.
For a young solver's first flight, start on 4x4 Easy in Both mode — four familiar tiles, sixteen cells, and a finished puzzle before the attention span burns up on re-entry.
One law of physics
Every puzzle here has a single solution and obeys the only rule that matters: no tile repeats in any row, column, or box. The Themed Sudoku page is ground control: it covers difficulty grading and the hint system, and lists the rest of the fleet for when you are ready to come back down to Earth.
Space Sudoku FAQ
The smaller boards use the first tiles in the set. A 4x4 puzzle uses the rocket, planet, star, and moon; the sun and comet join at 6x6; and the alien, telescope, and galaxy only appear on the full 9x9 board.
No — and we would rather be honest about that. It teaches logic: scanning, elimination, and justifying each placement. The space theme is a hook that gets space-mad kids to sit down with a real deduction puzzle.
Yes. The display selector switches between pictures, numbers, or both. Both mode adds a small number badge to each tile, which helps when the star, sun, and comet start to look alike at small sizes.