Play Nurikabe

Nurikabe game info

Rules

Nurikabe is played on a rectangular grid of cells. At the start, all cells are white and some contain a number. Horizontally or vertically connected white cells form islands. These cannot be connected to other islands!

The goal in Nurikabe is to determine for each cell whether it is part of an island (white dotted) or part of the sea (black), following these rules:

• Fill the grid with black and white (dotted) cells.
• White (dotted) cells form islands. Each island should contain exactly one numbered cell, which indicates the size of the island.
• Two islands may not be connected.
• Black cells form the sea. All black cells must be connected.
• The sea may not contain a 2x2 square of black cells.

Difficulties

Our version of the Nurikabe puzzle game has three difficulties: Small, Medium and Large.

How to solve a Nurikabe puzzle?

The best way to solve Nurikabe puzzles is to alternate between determining white cells and black cells. Once you determined a few black cells, this can lead to new information that helps to identify white cells, and vice versa.

Follow these tips to complete a Nurikabe puzzle:

• Cells between two islands must be black. If two numbers (or two cells of different islands) touch diagonally, the adjacent cells must be black.
• All cells surrounding a complete island must be black. This means all cells surrounding a 1 must be black.
• If there are 3 black cells in a 2x2 square, the fourth cell must be part of an island.
• All black cells must be connected to each other. If there is only one way for a group of black cells to be connected to the rest of the black cells, this cell must be black as well.
• If cells are unreachable by any island, they must be black.
• If you have determined a cell to be white and it can only be reached by one numbered region, it must be connected to this region.

Controls

You can play with the mouse or with the keyboard.

If you play using the mouse, you can select a cell by pressing it. Then select the number you want to fill in above the grid.

If you play using the keyboard, you can use the arrow keys to navigate through the grid. Press a number on your keyboard to fill it in. When playing with the keyboard you can use the following shortcuts: Undo (Z), Redo (Y), Reset (R), Save (S), Deselect (ESC), Erase cell (BACKSPACE).

Origin

The Nurikabe puzzle game was invented by Nikoli, a Japanese publisher specialized in logic puzzle games. The first Nurikabe puzzle appeared in March 1991 in a publication of Nikoli.

The puzzle is named after Nurikabe, a spirit of Japanese folklore that manifests as an invisible wall.

The Nurikabe game is sometimes also referred to as Cell Structure or Islands in the Stream, but Nurikabe remains the most widely adopted name.

Similar games

Other logic puzzle games on our website are Kakuro, Suguru and Binairo.

System requirements

Nurikabe can be played in all modern browsers, on all device types (desktop, tablet, mobile), and on all operating systems (Windows, macOS, Linux, Android, iOS, ...).