Frequently asked questions

Each number is the size of an island: a connected group of squares that holds that number and no other number. Shade the remaining squares as a single connected wall. The wall may never contain a 2x2 block of squares.

A dot marks a square you are sure belongs to an island. It is for your own notes. A puzzle counts as solved when the walls are right, so you never have to place dots.

Tap a square to cycle empty, wall, dot and back to empty. Drag across squares to paint several at once with whatever the first square becomes.

It highlights squares that already break a rule in red, such as a 2x2 block of wall, an island joining two numbers, or an island that has grown bigger than its number. You can switch it on and off while you play, or in Settings. It never affects whether a puzzle counts as solved.

Yes. Every puzzle has exactly one solution. Harder puzzles may need you to try a possibility and see whether it leads to a contradiction.

Easy and Medium puzzles can be solved with step-by-step deductions. Hard and Expert puzzles ask for more: you may need to test a possibility and see where it leads. Expert puzzles are on a 10x10 board.

Yes. A game in progress is saved when you leave the puzzle or close the app, and your solved puzzles and best times are kept. Everything is stored on your phone only.

Not at the moment. Progress lives on the device where you played. Deleting the app deletes its saved games and times.

Yes. Use Reset to clear the board, or Settings, then Reset all progress to clear every solved puzzle, best time and saved game.

No. Puzzles are bundled in the app or generated on your phone, so it works fully offline.

It stops your phone from dimming and locking while a puzzle is open. It is off by default and lets go as soon as you leave the puzzle.

No. All themes are free. Choose one in Settings.

Yes, a gentle tap as you mark squares, a firmer one for walls, a buzz when a move breaks a rule, and another when you solve a puzzle. You can switch haptics off in Settings.

iPhone, in portrait orientation, on iOS 17 or later. iPad is not supported yet.

Please write to support@nurikabe.app. See the Support page for what to include.