Nurikabe: Island Logic Puzzle

Nurikabe (also known as Islands in the Stream) is a relaxing Japanese logic puzzle. Paint the walls, leave the islands — every puzzle has exactly one solution, found by pure deduction, never by guessing.

What is Nurikabe?
Nurikabe (ぬりかべ, "painted wall") is a classic Japanese logic puzzle from the makers of Sudoku, Nikoli. The rules are simple, the deductions are deep:
• Paint cells to build one connected wall; leave the rest white as islands.
• Each numbered cell belongs to exactly one island whose size equals the number.
• The wall must stay a single connected shape, and no 2×2 area may be solid wall.
• Islands may only touch diagonally — never side by side.

Every puzzle in this app has exactly one solution and is solvable by logic alone — never by guessing.

Three ways to play
• Journal — 1,200 hand-picked levels across 100 pages of a stamped, stationery-style journal. Solve a page, earn its stamp.
• Free play — pick any size from 5×5 to 12×12 and solve at your own pace, no limit on boards.
• Survival — solve puzzle after puzzle to buy time before the ink dries. Chase your best run on the worldwide leaderboard.

Features
• 1,200 hand-picked levels, plus unlimited free-play boards from 5×5 to 12×12.
• A stamp case of 15 achievements — from your very first solve to survival close calls.
• A live-clock survival mode with a worldwide leaderboard.
• Full offline play — no internet required, no account, no nag.
• A quiet, stationery-inspired look in light and dark, that follows your system.
• High-contrast mode and a colour-blind-safe palette.
• Cell states distinguished by shape AND fill — accessible by design.
• Smart hints when you're stuck (opt-in, never forced).
• Undo / redo and an auto-save that resumes exactly where you left off.
• Pinch-zoom and pan on large grids.
• Localized in 32 languages with proper font support for CJK, Arabic, Hindi, Thai and more.
• A small download — nothing to wait for.

Calm by design — and rating-safe
• No ads while you solve. Ever. The play screen has zero ad chrome.
• Journal and Free Play have no timer — solve at your own pace.
• A gentle completion celebration, then straight back to the page.
• Optional sound and haptic feedback that you can fully disable.

Brain training that travels with you
A logic puzzle is one of the best low-effort habits for keeping your mind sharp. Nurikabe works on the bus, on a flight, in waiting rooms — anywhere, offline.

Free to play
Nurikabe is free. An optional one-time "Remove ads" purchase removes the completion-screen interstitial. Survival's pen refill — an optional rewarded video, once per run — stays free for everyone.

Paint the walls, leave the islands. Free to play.