Nurikabe: Logic Puzzles

Paint islands of white, seas of black. Nurikabe is a classic Japanese logic puzzle that rewards patience over speed — no timers, no penalties, no guessing required. Every puzzle has exactly one solution, and every solution can be reached with pure deduction.

How it works

The grid starts with numbered cells. Your job is simple to learn:

• Each number is an "island" — a connected group of white cells whose size matches the number.
• Every other cell becomes part of the black "sea."
• Islands can never touch each other horizontally or vertically.
• The black sea must be fully connected.
• The sea can never contain a 2×2 block of black cells.

That's it. Five rules, endless depth.

Features

🟦 Hand-crafted puzzles — Every grid is verified to have a unique, logic-only solution. No coin-flips, no dead ends.

🎚️ Difficulty for everyone — From gentle 5×5 introductions to brain-bending 20×20 grids. Start where you're comfortable and grow into harder packs at your own pace.

✏️ Smooth, tactile input — Tap to mark a cell, drag to paint a row, long-press to add a pencil mark. Mistakes are easy to undo, and the grid never fights you.

🧠 Helpful, never hand-holding — Optional hints highlight the next logical step rather than solving the puzzle for you. Turn them off entirely for a pure challenge.

🌙 Dark mode and high-contrast themes — Designed to be easy on the eyes for long sessions.

📴 Plays fully offline — Take it on flights, commutes, or anywhere without signal. Your progress saves automatically.

♿ Accessibility built in — Adjustable cell size, colorblind-friendly palettes, and full screen-reader support.

Why Nurikabe?

Sudoku trains arithmetic constraint. Picross trains pattern matching. Nurikabe trains spatial reasoning — the same kind of thinking that goes into routing, network design, and topology. It's quietly one of the most satisfying logic puzzles ever invented, and we've tried to give it the careful, unhurried home it deserves.

Whether you want a five-minute coffee-break puzzle or a forty-minute meditative grind, Nurikabe is built to fit the time you have.

Made by FishtailGames

A small studio building the kind of puzzle games we want to play ourselves: clean, fair, respectful of your time and attention.