How to play Nurikabe

Shade a winding sea around numbered islands.

Play Nurikabe

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The goal

Shade squares to make one connected sea, so that every number sits in an island of exactly that many squares.

The rules

Each number is part of an island: a group of unshaded squares joined side by side. The island has exactly as many squares as its number.
Every island has exactly one number. Two islands may touch at a corner, but never along a side.
All the shaded squares (the sea) join up into one piece, side by side.
The sea has no pools: no 2×2 block may be all shaded.

Playing

Tap a square to shade it, tap again to put a dot in it (a square you’ve decided is island), and tap once more to clear it.
Drag across squares to paint them all the same way as the first one. Dragging out of a number paints dots.
Undo takes back your last change. Clear wipes the board, and can be undone too.
The puzzle is solved the moment the shaded squares are exactly the sea. Dots are just notes for you.

Checking your work

Shaded squares turn red if they form a 2×2 pool, or if they’re cut off from the rest of the sea.
An island turns red if it has two numbers, more squares than its number, or is walled in too small. Dots walled in with no number turn red too.
A number fades once its island is the right size and walled in by sea.
Check rings any square you’ve marked wrong. Hint fixes a wrong mark, or fills in a square that follows from the board.

Tips

Shade all around a 1 straight away: its island is already complete.
A square between two numbers, side by side or diagonally, must be sea, or it would join two islands.
Shade any square no island can reach.
Where three squares of a 2×2 block are shaded, the fourth must be island.
A patch of sea that has only one way out must use it, to join the rest of the sea.

Difficulty

Easy: a 6×6 grid you can solve one step at a time with the rules above.
Normal: an 8×8 grid with bigger islands.
Hard: a 10×10 grid where some steps need a “what if”: try a square both ways and see which one breaks a rule.
Every puzzle is new and has exactly one answer. Your best times are kept for each difficulty.

Keyboard

Arrow keys move, Space or Enter taps, S shades, D or . dots, Backspace clears, H hints, C checks, and Ctrl or ⌘+Z undoes.

Questions

How do you win Nurikabe?

Shade squares to make one connected sea, so that every number sits in an island of exactly that many squares.

Is Nurikabe free to play?

Yes. Nurikabe on Everyday Games is free and plays in your web browser on phones, tablets and computers, with nothing to download.

Do I need an account to play?

No. You can play without signing in, and your stats and games in progress are saved in your browser. Sign in with Google or Apple to keep them in your account and pick up where you left off on any device.

What modes does Nurikabe have?

You can play Easy, Normal or Hard. Your record (games played, wins and best results) is kept separately for each.

Strategy guides