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Overview
Fillomino icon FI

Fillomino

1 player · 3-15 min per session

Fill every cell so each side-connected region contains exactly as many cells as the number inside it. Separate regions with the same number may not touch side to side.

Players: 1P Session length: 3-15 min
PuzzleNumber

Goal & Core Rules

Fill every cell so each side-connected region contains exactly as many cells as the number inside it. Separate regions with the same number may not touch side to side.

  • Select a cell and enter a number. Same numbers join into one visible region, so you build the puzzle by filling numbers instead of drawing walls yourself.
  • A finished 1 is a single cell, a 2 covers exactly 2 side-touching cells, a 3 covers 3, and so on.
  • Two different regions with the same size may not share a side. In short: the same number cannot sit on both sides of a region boundary.
  • This build offers Easy 5x5, Normal 6x6, and Hard 7x7 boards.
  • Each generated puzzle here starts with exactly one clue in every final region, and the puzzle clears when every cell matches the finished layout.

Current implementation in this build

This is a number-entry Fillomino, not a manual border-drawing editor. You select a cell, enter a value from the on-screen keypad or keyboard, and the game shows region lines automatically from the numbers you have placed. It also includes hint, restart, export, and load features, so it feels closer to a guided digital puzzle than a bare paper grid.

Classic paper Fillomino

In many books and magazines, solvers think in terms of borders first: they sketch region edges, add missing numbers as notes, and gradually prove which cells belong together. The core rule is the same as this build, but the play feel is different. Here you never draw the walls yourself; filling numbers is enough, and the game visualizes the region borders for you.

One clue per region here vs looser clue layouts elsewhere

In widely known Fillomino rules, a finished region can sometimes have no starting clue at all, and two matching givens may even end up inside the same final region. This build does not use that looser clue style. Every final region starts with exactly one given number, which makes the opening more approachable and keeps the board easier to read for casual players.

Friendly digital helper features in this version

Some Fillomino versions leave almost all checking to the player until the end. This version is gentler. Wrong numbers are highlighted against the finished solution, Hint locks one correct cell, and Restart clears your entries on the same board. That makes it easier to learn patterns without getting stuck for too long.

Other published Fillomino-family variants

The wider Fillomino family also includes alternate presentations such as Allied Occupation, and Wikipedia notes related experiments on other grid types. Those are not what you play here. This build stays with the standard square-grid number-region format because it is the easiest version for most players to pick up quickly.

Controls

Mouse

  • Click a cell to select it, then click a number button to fill it
  • Right click a cell to clear it quickly
  • Use the top menu for new game, restart, hint, help, export, and load

Keyboard

  • Arrow keys move the current selection
  • Number keys and numpad keys enter values
  • 0, Delete, or Backspace clears the selected cell
  • H uses a hint

Touch

  • Tap a cell to select it, then tap a number on the keypad
  • Use Clear to erase your current entry and Hint to lock one correct cell
  • Use the top menu for new game, restart, help, export, and load

Beginner Tips

  • Start with 1s and tight corners. Small regions reveal their shape faster and often force nearby borders right away.
  • When a group of matching numbers is already as large as its number, treat the cells next to it as forbidden for that same region size.
  • Do not try to read the whole board at once. Pick one clue, ask how far it can grow, then check whether the same number would illegally touch another region.

Advanced Tips

  • Count both growth and overload. A region must become large enough, but it also has to stop before it spills into too many cells.
  • Use the auto-borders as feedback. If a number choice creates an awkward split or leaves a nearby clue no room to expand, that branch is probably wrong.
  • On the 7x7 hard boards, switch between local deductions and whole-board space checks. Big regions often look flexible until another same-size region nearby steals the only safe cells.

Origins & History

Fillomino is a Japanese logic puzzle published through Nikoli's Puzzle Communication magazine. Wikipedia describes it as appearing in Japan in the 1980s and later being republished by many puzzle publishers in other countries. The larger Nikoli story helps explain that spread: founder Maki Kaji built a culture around hand-crafted, language-light puzzles, and Reuters and The New York Times later described how that approach helped Japanese puzzle design reach a global audience.

Notable People

  • Nikoli Japanese puzzle publisher that published and popularized Fillomino.
  • Maki Kaji Nikoli founder whose puzzle-publishing culture helped Japanese logic games gain a worldwide audience.

Trivia

  • Wikipedia notes that completed Fillomino answers can be communicated using just the numbers, because the region borders become obvious once every cell is filled.
  • Another published title for the same puzzle family is Allied Occupation.

FAQ

Do I draw region borders in this version?

No. This build uses the easier digital style: you fill numbers, and the game shows the region borders automatically from the values on the board.

Is this exactly the same as every printed Fillomino puzzle?

Not quite. The core idea is the same, but this build is friendlier: each final region begins with one clue, wrong cells are highlighted, and you can use hints, export, and load.

Does Restart make a brand-new puzzle?

No. Restart clears your current input and hints on the same board. Use New Game when you want a fresh puzzle or a different difficulty.

Can I save my current progress?

Yes. The top menu includes Export and Load, so you can copy your current board state into a code and continue later.

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