Nurikabe

Decide which cells are sea (shaded) and which are island (white).

• Every island contains exactly one number, and that number is the island's size in cells.
• Islands never touch each other side by side.
• All sea cells form one connected body of water (connected side by side).
• The sea may never contain a 2×2 pool of shaded cells.

Controls

• Tap a cell to cycle: empty → sea → • dot (island) → empty.
• Right-click or long-press toggles a dot. Drag to paint sea (or dots) across many cells.
• Keyboard: arrows move, Space cycles, X toggles a dot, Ctrl+Z undoes.

2×2 pools, islands with too many cells or two numbers, and closed-in islands that are too small are shown in red. Check highlights mistakes and Hint fixes one cell. Every puzzle has a unique solution.

Tips

Cells between two numbers must be sea. Islands of 1 are surrounded by sea. Any cell no island can reach is sea, and a sea region that has only one way out must flow through it.