Just Puzzles

Just Nurikabe

Shade the sea. Each number sits on an island of exactly that size, the sea is one connected body, and it never fills a 2×2 block.

Today's board

One board a day, the same one as in the app.

Play today's board

A new board

Size
Difficulty

The rules

  1. Each number sits on an island of exactly that many cells.
  2. Islands never touch along an edge, and each holds one number.
  3. The sea is one connected body.
  4. The sea never fills a 2×2 block.

Tap a cell to shade it as sea. Tap again for a dot, your own note that the cell is land, and once more to clear it. Drag to paint several cells. With a keyboard: arrow keys move, Space cycles a cell.

1311112

The techniques

The solver that builds each board knows 9 named techniques, listed here in the order it reaches for them. A board is kept only if they are enough to finish it.

  1. Ones
  2. Between Two Islands
  3. Finished Island
  4. No Pools
  5. Out of Reach
  6. Only Way Out
  7. The Sea Must Connect
  8. Common Ground
  9. What If

Questions

Do I ever have to guess in Nurikabe?

No. Every board is proved to have exactly one solution before it reaches you, and each step can be reasoned out.

Is Nurikabe free to play here?

Yes. Today's board and new 5×5 and 7×7 boards at every difficulty are free, with no account and no ads. The 10×10 boards, the lessons and the hints come with Just Nurikabe, the app, which is on its way to the App Store.

Is today's board the same as in the app?

Yes. The daily board is made from the date, so this site and the app serve the same one.

Along the street

  • Shikaku: divide the room into rectangles
  • Hashi: learn to build the bridges
  • Kakuro: learn the crossword of sums
  • Keisan: cages, sums and a Latin square
  • Takegaki: draw one loop, count the sides
  • Masyu: one loop through every pearl

In the app

Just Nurikabe is on its way to the App Store: nine named techniques, each with its own lesson, hints that explain their argument on your board, and 10×10 boards.