You complete Nurikabe when every white component contains exactly one clue with its stated size, all black cells connect, and no black two-by-two block exists. The full Nurikabe position determines the outcome; visual shortcuts never replace the documented Nurikabe terminal rule.
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You complete Nurikabe when every white component contains exactly one clue with its stated size, all black cells connect, and no black two-by-two block exists. The full Nurikabe position determines the outcome; visual shortcuts never replace the documented Nurikabe terminal rule.
Complete guide
Nurikabe uses the independently implemented Nikoli Nurikabe rules v1 profile (R358). Nurikabe is a complete deterministic browser game built around numbered white islands of exact size separated by one connected black sea that may never contain a two-by-two black block.
Nurikabe begins with a rectangular clue grid where each numbered cell anchors one island and every unclued cell begins undecided. The Nurikabe deal identity and Nikoli Nurikabe rules v1 are stored together. Restarting Nurikabe reproduces this opening exactly.
During Nurikabe, you mark an undecided cell black or white, clear a reversible mark, and receive contradiction feedback for merged clues, wrong island size, disconnected sea, or black squares. The Nurikabe engine rejects profile violations, unavailable material, and every action attempted after Nurikabe reaches a terminal result.
You complete Nurikabe when every white component contains exactly one clue with its stated size, all black cells connect, and no black two-by-two block exists. The full Nurikabe position determines the outcome; visual shortcuts never replace the documented Nurikabe terminal rule. In the Nurikabe endgame, check every undecided cell against both island capacity and sea connectivity, then resolve the final no-two-by-two constraint. Check every remaining Nurikabe action before committing because its terminal rule is enforced immediately.
A reliable Nurikabe plan is to surround completed islands, separate nearby clues immediately, and extend forced sea cells while preserving a path between black regions. A Nurikabe hint is legal and deterministic. The next Nurikabe hint exposes one bounded action; it never claims a forced Nurikabe win. A costly Nurikabe mistake is to grow two numbered islands into one white component or close a black pocket that can no longer connect to the main sea. Undo supports studying that Nurikabe decision, while restart preserves the original seeded Nurikabe opening.
Nurikabe uses numbered white islands of exact size separated by one connected black sea that may never contain a two-by-two black block. That rule belongs to the Nurikabe engine and storage identity rather than a cosmetic preset.
Diagonal contact does not connect white islands or black sea cells; connectivity is orthogonal throughout the puzzle.
Nurikabe records its game ID, rules version, and seeded deal identity. Those Nurikabe values recreate the same opening without a server request.