How to Play Nurikabe

THE PLAYBOOK · 850305

How to play Nurikabe

Use 850305 to play Nurikabe and read its instructions on the same page. Create one connected sea around numbered islands of exactly the stated size, without a 2×2 sea block. Follow the mistake-aware practice approach for your next round.

Ten checked compact 5×5 boards with fixed sea starters in some puzzles.

Mistake-aware practice

Read the common mistake below before starting. Watch for that situation during the round rather than relying on trial and error.

Your goal

Create one connected sea around numbered islands of exactly the stated size, without a 2×2 sea block.

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.

A useful example

An island labelled 1 is already complete, so its edge neighbours must be sea.

Watch out for this

Two numbered islands may not merge into one.

Common questions