Nurikabe

Build islands from numbered clues while keeping the sea connected.

How to Play

Each number is an island clue. Mark cells as island or sea until all rules are true:

1. Every island contains exactly one clue.
2. Island size equals clue value.
3. All sea cells are one connected region.
4. No 2x2 sea block is allowed.

Clue cells are fixed and always island cells. Once every sea cell is marked, any remaining undecided non-sea cells count as island for completion.

Controls

Key	Action
Arrow keys / WASD / hjkl	Move cursor
x	Set sea
z	Set island
Backspace	Clear to unknown
Ctrl+R	Reset puzzle
Ctrl+H	Toggle full help
Escape	Return to main menu

Mouse

Action	Effect
Left click	Move cursor, or set sea on the current cell
Left drag	Paint sea from the current cell
Right click / drag	Set island cells

Modes

Mode	Grid	Description
Mini	5x5	Gentle introduction
Easy	7x7	Balanced logic
Medium	9x9	Moderate deduction
Hard	11x11	Lower clue density
Expert	12x12	Sparse clues and longer chains

Elo Difficulty

Named modes are compatibility presets. Use --difficulty <0..3000> to target a specific Elo difficulty for generated puzzles.

Quick Start

puzzletea new nurikabe mini
puzzletea new nurikabe medium
puzzletea new nurikabe expert
puzzletea new islands easy       # alias