Raster: Sudoku Variants

Ten stages, each one a solving technique. Hints that teach the technique instead of giving away the digit. Killer, Thermo, Jigsaw and twelve more rule sets.

Sudoku with an honest difficulty scale. Each of the ten stages stands for one solving technique: the hardest one the puzzle needs. Nothing ever requires guessing.

• 10 stages, from the last empty cell to X-Wing, Swordfish and forcing chains • Hints that name the next technique and point to the cells, not the digit • 15 rule sets: Classic, Killer, Thermo, Slow Thermo, Arrow, Jigsaw, X-Sudoku, Hyper/Windoku, Even/Odd, Sandwich, Kropki, XV, Renban, German Whispers and Between Line • Classic and Jigsaw also on a 6×6 grid • Fog of War: the grid only clears around correctly placed digits • A daily puzzle with a fixed weekly rhythm: gentle on Monday, hardest on Saturday • A handbook to look up every technique you have met and every variant rule • Nearly 5,000 puzzles, each with a unique solution and rated by the solver • Notes and auto-notes, undo, three error-display modes, optional timer, stars, best times and statistics • Works offline, no account needed

WHY STAGES INSTEAD OF EASY, MEDIUM, HARD “Hard” means something different in every app. Raster rates every puzzle the way the sudoku community does: by the hardest human technique it requires. Stage 7 is not more of the same; it is where you need triples. When you reach a new stage, a short card shows the new technique with a worked example, so the ladder doubles as a course.

VARIANTS WITH THEIR OWN LADDER Every variant is calibrated on the same 1–10 scale, so a stage 5 Killer feels as hard as a stage 5 Classic. The first time you meet a rule, a card explains it with a small solved example.

Raster is free to play. After a solved puzzle a short ad is shown; a one-time in-app purchase removes it for good.