Sudoku and Nurikabe are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Nurikabe is distant to Sudoku. Below we lay out what the two share, where they part ways, and whether the skills you have built on Sudoku will carry over.
- Grid: Rectangular
- Closeness to Sudoku: Distant
- Also called: Islands in the Stream
What is Nurikabe?
Shade cells into a connected "sea" so that each numbered cell forms an island of exactly that many unshaded cells. Here are the rules in full:
- Each number is an island of that many connected unshaded cells; islands never touch orthogonally.
- All shaded cells form one connected sea.
- The sea contains no 2×2 fully shaded block.
See a Nurikabe grid
Nurikabe shades cells into a connected "sea" so each numbered cell is an island of exactly that many unshaded cells, islands never touch, and the sea has no 2×2 block. Below, a "3" island (white) surrounded by sea (dark).
A "3" island (three white cells) in a connected sea (dark).
It is a pure-logic, single-solution puzzle solved by ruling regions in or out from local constraints. But you shade cells into islands and sea rather than placing numbers, and connectivity and the no-2×2 rule have no counterpart in Sudoku — a distant relative.
What Nurikabe shares with Sudoku
- It is a pure-logic, single-solution puzzle solved without guessing.
- Both puzzles progress by ruling regions in or out from local constraints.
How Nurikabe differs from Sudoku
- You shade cells into islands and sea rather than placing numbers.
- Connectivity and the no-2×2 rule have no counterpart in Sudoku.
Do Sudoku skills transfer?
The tools don't transfer, but the mindset does: chase the forced cells first, and never shade on a hunch — the same patience Sudoku demands.
The verdict
Nurikabe is a region-shading puzzle that shares Sudoku's logic-only ethos but none of its number play.