Nurikabe

THE PLAYBOOK · SJZYCGG

How to play Nurikabe

Use a short break to learn the rhythm of Nurikabe. Create one connected sea around numbered islands of exactly the stated size, without a 2×2 sea block. Look at what changes after your first action. Identify the playing area and the controls you need. Check the relevant rule before repeating a move.

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

Try a deliberate move

After a move, check what changed. Decide which rule explains the new state before acting again. Use the example to check your reasoning.

Your goal

Create one connected sea around numbered islands of exactly the stated size, without a 2×2 sea block. The feedback beside the game helps you follow the round. Return to the instructions when a step is unclear.

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. On a smaller screen, keep the active part of the board within view. A new-round button replaces the current round.

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. Take a moment to compare.

Watch out for this

Two numbered islands may not merge into one. Compare the situation with the worked example. Watch the feedback after an action. A message can explain whether the input was accepted or whether a rule needs attention.

Common questions