Logic Puzzle Club

Nurikabe of the week: week 4

The full logical solve of the hard Nurikabe for September 22 to September 28, 2026, 12 × 12. 82 steps, 7 techniques, no guessing. Step through it, or jump to any step below.

Island complete. The 1 in row 2, column 8 is a whole island by itself. Every open cell beside it is sea.
Step 1 of 82

Every step

  1. The 1 in row 2, column 8 is a whole island by itself. Every open cell beside it is sea.

  2. The 1 in row 6, column 7 is a whole island by itself. Every open cell beside it is sea.

  3. The 1 in row 10, column 4 is a whole island by itself. Every open cell beside it is sea.

  4. The 1 in row 11, column 10 is a whole island by itself. Every open cell beside it is sea.

  5. The 1 in row 11, column 12 is a whole island by itself. Every open cell beside it is sea.

  6. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  7. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  8. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  9. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  10. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  11. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  12. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  13. The 2 in row 9, column 10 has 1 of its 2 cells and only one open neighbor. It must grow through that cell.

  14. The 2 in row 9, column 10 already has all 2 of its cells. Every open cell beside it is sea.

  15. The 2 in row 11, column 5 has 1 of its 2 cells and only one open neighbor. It must grow through that cell.

  16. The 2 in row 11, column 5 already has all 2 of its cells. Every open cell beside it is sea.

  17. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  18. The 2 in row 12, column 3 has 1 of its 2 cells and only one open neighbor. It must grow through that cell.

  19. The 2 in row 12, column 3 already has all 2 of its cells. Every open cell beside it is sea.

  20. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  21. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  22. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  23. The 2 in row 10, column 1 already has all 2 of its cells. Every open cell beside it is sea.

  24. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  25. No numbered island can reach these 11 cells with the cells it has left. They are sea.

  26. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  27. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  28. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  29. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  30. The 2 in row 7, column 2 already has all 2 of its cells. Every open cell beside it is sea.

  31. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  32. The 2 in row 8, column 5 already has all 2 of its cells. Every open cell beside it is sea.

  33. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  34. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  35. The 2 in row 11, column 7 already has all 2 of its cells. Every open cell beside it is sea.

  36. No numbered island can reach this cell with the cells it has left. It is sea.

  37. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  38. Suppose row 9, column 7 is sea. Following the rules from there breaks one of them, so it is island.

  39. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  40. The 5 in row 9, column 6 has 4 of its 5 cells and only one open neighbor. It must grow through that cell.

  41. The 3 in row 8, column 9 has 1 of its 3 cells and only one open neighbor. It must grow through that cell.

  42. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  43. Suppose row 7, column 10 is island. Following the rules from there breaks one of them, so it is sea.

  44. The 3 in row 8, column 9 has 2 of its 3 cells and only one open neighbor. It must grow through that cell.

  45. The 3 in row 8, column 9 already has all 3 of its cells. Every open cell beside it is sea.

  46. These island cells have no number yet and only one open neighbor. They must reach a number through that cell.

  47. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  48. These island cells have no number yet and only one open neighbor. They must reach a number through that cell.

  49. The 4 in row 5, column 10 already has all 4 of its cells. Every open cell beside it is sea.

  50. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  51. Suppose row 3, column 10 is island. Following the rules from there breaks one of them, so it is sea.

  52. These island cells have no number yet and only one open neighbor. They must reach a number through that cell.

  53. The 3 in row 3, column 11 already has all 3 of its cells. Every open cell beside it is sea.

  54. Suppose row 3, column 9 is island. Following the rules from there breaks one of them, so it is sea.

  55. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  56. These island cells have no number yet and only one open neighbor. They must reach a number through that cell.

  57. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  58. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  59. These island cells have no number yet and only one open neighbor. They must reach a number through that cell.

  60. No numbered island can reach this cell with the cells it has left. It is sea.

  61. Three cells of this 2×2 square are sea. If the fourth were sea too it would make a pool, so it is island.

  62. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  63. Suppose row 2, column 5 is sea. Following the rules from there breaks one of them, so it is island.

  64. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  65. Suppose row 2, column 4 is sea. Following the rules from there breaks one of them, so it is island.

  66. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  67. Suppose row 2, column 3 is sea. Following the rules from there breaks one of them, so it is island.

  68. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  69. Suppose row 3, column 3 is island. Following the rules from there breaks one of them, so it is sea.

  70. Suppose row 2, column 2 is sea. Following the rules from there breaks one of them, so it is island.

  71. The 6 in row 3, column 2 already has all 6 of its cells. Every open cell beside it is sea.

  72. The 5 in row 3, column 7 has 4 of its 5 cells and only one open neighbor. It must grow through that cell.

  73. The 5 in row 3, column 7 already has all 5 of its cells. Every open cell beside it is sea.

  74. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  75. This piece of sea has only one open neighbor. All the sea joins into one piece, so that cell is sea.

  76. Suppose row 4, column 3 is island. Following the rules from there breaks one of them, so it is sea.

  77. The 4 in row 4, column 4 has 1 of its 4 cells and only one open neighbor. It must grow through that cell.

  78. This open cell touches two numbered islands. As island it would join them into one island with two numbers, so it is sea.

  79. The 2 in row 5, column 2 has 1 of its 2 cells and only one open neighbor. It must grow through that cell.

  80. Suppose row 5, column 5 is island. Following the rules from there breaks one of them, so it is sea.

  81. The 4 in row 4, column 4 has 2 of its 4 cells and only one open neighbor. It must grow through that cell.

  82. The 4 in row 4, column 4 already has all 4 of its cells. Every open cell beside it is sea.