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.
Where to play it
If it was Sudoku you came for, the level is the choice that matters more than the variant - Nurikabe and Sudoku part ways on the rules, but a Sudoku grid can be a two-minute warm-up or an hour of work depending on nothing but how much of it you are given.
Difficulty and type are two separate dials here: the type sets the extra rule, the level sets how much of the grid you start with. Easy Sudoku leaves 36 of the 81 cells filled, so there is always an obvious next move somewhere; Evil Sudoku leaves 23, with no easy moves at all. Take it at the gentler end while the pattern is still new, and move up once it stops being a fight.