Learn Fillomino

Fillomino is a logic puzzle about dividing a grid into regions. Every rule fits in one sentence, yet a 16×16 board can keep you thinking for an hour. These pages explain the rules, teach the techniques experienced solvers use, and give you printable puzzles to practise on.

If you have never played, start with the rules and the small example there. Then read the three technique articles in order: each one builds on the last, and together they cover the reasoning you need for every easy and medium puzzle in the app. Hard puzzles mostly combine these same ideas over longer chains.

• The rulesWhat a valid solution looks like, with a small worked example and its answer.
• First movesThe three deductions that start almost every puzzle: complete regions, separated clues, and the only way out.
• Enclosed areasWhat to write in a pocket of empty cells that no clue can reach.
• Reach and roomCounting distance and space to place big regions.
• Tips and common mistakesHabits that make large grids manageable, and errors that cost the most time.
• Where Fillomino comes fromPolyominoes, Nikoli, and how a pencil puzzle became an app.
• Printable puzzlesSix 8×8 puzzles with solutions, to print or solve on screen.

How the puzzles in the app are made

Every puzzle in Fillomino is checked by a solver before it ships. Medium and hard puzzles have exactly one solution under the standard rules, so you never need to guess. If you reach a point where nothing seems forced, there is always a logical step somewhere on the board; the hint button will show you one cell that can be deduced, without counting against your solve time.