How to Play Nurikabe

THE PLAYBOOK · 360-L

How to play Nurikabe

Nurikabe gives you a focused activity to play in your browser. Create one connected sea around numbered islands of exactly the stated size, without a 2×2 sea block. Use the example below to understand a decision. Choose a comfortable screen position before beginning. Look at what changes after your first action.

Play ten compact 5×5 puzzles. Some boards begin with fixed shaded sea cells.

Read before acting

Read one step at a time and try it on the playing area. Match the instruction to the control you use. Notice the feedback after each input.

Your goal

Create one connected sea around numbered islands of exactly the stated size, without a 2×2 sea block. An attractive position is not enough unless the goal is met. Check the rules when you are unsure.

Step by step

1. Shade sea squares and leave islands white.
2. Every island contains exactly one clue.
3. Different islands cannot meet along an edge.
4. Check puzzle verifies sizes, connectivity and forbidden sea blocks.

Controls

Click or tap squares or graph edges. Number boards include a digit pad. Undo reverses the previous change; Check puzzle validates the solution. Use the control method described here for this activity. Use the visible help when you are unsure of the next input.

A useful example

An island labelled 1 is already complete, so its edge neighbours must be sea. Your next round may have a different position, so inspect it before acting. Notice the change in the playing area.

Watch out for this

Two numbered islands may not merge into one. Take a moment to reassess the position before continuing. When a decision goes wrong, compare it with the common mistake described below. Start again only when you intend to leave the current round.

Common questions