New to Nurikabe? Learn the four rules on a 6×6, then get used to thinking wall first: the squares around complete islands, between islands, and out of reach of every island are all wall. This page puts the guides in that order, with six small warm-ups to check yourself before you move up a size.
Your path, in order
- Learn the rules. The Nurikabe rules page solves the game’s first level step by step. The one idea to take away: every number is an island of that many squares, and everything else is one joined-up wall with no 2×2 blocks.
- Wall in the 1s and every island as soon as it’s complete.
- Wall every square between two islands.
- Ask how far each island can reach. Everything else is wall.
- Do the warm-ups below. Six small grids, each featuring an idea from the guides.
- Learn the other techniques. How to solve Nurikabe covers all seven.
- When a puzzle goes wrong, read the six common mistakes. The big one is shading a square before it’s certain.
- Move up a size when you’re ready (see below).
Warm-up: six small puzzles
Each has exactly one solution. Every one needs the 2×2 rule somewhere, since that’s how most island squares get found on small grids. Solve it, then open the answer.
1. Out of reach
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Each 2 can only reach the squares beside it, so the nine squares two or more steps from every number are wall. Now look at the top-left corner: three of those walls make a 2×2 block with row 2, column 1, so that square is island, and it completes the 2 above it. Wall it in. The same pattern finishes each of the other 2s.
2. Between islands
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Row 3, column 1 touches the 2 above it and the 2 below it, so it’s wall. Ten more squares are out of reach of every 2. Then, as in the first warm-up, each 2×2 block of three walls gives an island its second square, and each complete island gets walled in.
3. An island with one way to grow
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Four 2s in a square: the four squares between them are wall, and so is everything out of reach. Now the two 2s in the top row are each walled in on every side but one, so each grows outwards into its corner. The two 2s in row 3 get their second squares from 2×2 blocks below them.
4. A wall with one way out
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The square between the two 2s in row 4 is wall, then the squares out of reach, then 2×2 blocks complete two of the islands. Now the wall in the top-left corner, rows 1 and 2 of column 1, is closed in on every side but one: to join the rest of the wall, it has to go down to row 3. That leaves the 2 in row 4 only one way to grow, downwards.
5. Everything so far
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Wall in the two 1s, then the squares between 2s (row 2, column 3 and row 3, column 2), then eleven squares out of reach. The 2 in the top row grows left, its only way out, and the wall in the top-left corner can then only join up by going down. A 2×2 block and a few islands with one way to grow finish it.
6. A bigger mix
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Wall in the two 1s and the square between the two 2s in the bottom row, then nine squares out of reach. The 2 on the right edge can only grow down. The wall square between the bottom 2s has only one way out, upwards. From there, a 2×2 block, islands with one way to grow, and one more wall with one way out finish it.
When to move up a size
You’re ready for Medium (8×8) when you can finish Easy levels without guessing, and you look for squares out of reach without thinking about it. Out of reach is the most used technique on every track: 10.6 times per Easy level on average, 15.8 on Medium and 22.6 on Hard. From Medium on, 44 of the 50 levels also need what-if, and every Hard one does.