Nurikabe
Hard
00:00
Classic
Hard Nurikabe — what to expect
Hard Nurikabe keeps Medium’s 8×8 board and raises the thinking instead. This is where you have to ask which cells no island can reach, working around the walls rather than straight out from a clue. Same size, same clue density — the step up is entirely in the kind of deduction, which is why it is worth sitting with rather than rushing.
How to play Nurikabe
- Every cell ends up one of two things: island, left white, or sea, shaded black.
- Each number is the SIZE of its island — that many white cells joined edge to edge, with the number itself counted among them.
- Every island holds exactly one number. So a 1 is finished where it stands, and the four cells beside it — above, below, left and right — are sea. Its corners are free.
- Two islands never sit side by side. Meeting at a corner is fine — a finished board is full of diagonal contacts.
- All the black cells join into one single sea. Nothing may be walled off from the rest of it.
- No 2×2 block may be entirely sea. When three corners of one are black the fourth has to be white, and that is where many boards open up.
- Every puzzle has one solution, reachable by logic alone, and every board has a move you can make from the empty grid.