The full logical solve of the hard Light Up for September 1 to September 7, 2026, 14 × 14. 48 steps, 5 techniques, no guessing. Step through it, or jump to any step below.
The 0 at row 1, column 7 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 11, column 14 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 12, column 7 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 13, column 3 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 14, column 8 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 14, column 10 has no bulbs beside it, so none of its open sides can take one.
The 4 at row 10, column 9 still needs four bulbs and has exactly four open sides. Every one takes a bulb.
The 2 at row 13, column 1 still needs two bulbs and has exactly two open sides. Every one takes a bulb.
The 1 at row 8, column 1 still needs one bulb and has exactly one open side. It takes the bulb.
The 2 at row 6, column 2 still needs two bulbs and has exactly two open sides. Every one takes a bulb.
The 2 at row 1, column 2 still needs two bulbs and has exactly two open sides. Every one takes a bulb.
The 1 at row 1, column 5 still needs one bulb and has exactly one open side. It takes the bulb.
The 1 at row 9, column 2 still needs one bulb and has exactly one open side. It takes the bulb.
The 1 at row 12, column 3 still needs one bulb and has exactly one open side. It takes the bulb.
The 1 at row 10, column 4 still needs one bulb and has exactly one open side. It takes the bulb.
Suppose a bulb sat at row 1, column 13. Its light closes the cells it reaches, and the 2 at row 2, column 14 would be left without room for its bulbs. So that cell has no bulb.
Nothing else can light the cell at row 1, column 14: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
Suppose a bulb sat at row 3, column 13. Its light closes the cells it reaches, and the 2 at row 2, column 14 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 5, column 12. Its light closes the cells it reaches, and the 2 at row 6, column 13 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 5, column 14. Its light closes the cells it reaches, and the 2 at row 6, column 13 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 7, column 11. Its light closes the cells it reaches, and the 1 at row 8, column 10 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 8, column 12. Its light closes the cells it reaches, and the 1 at row 7, column 13 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 13, column 12. Its light closes the cells it reaches, and the 2 at row 14, column 13 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 13, column 14. Its light closes the cells it reaches, and the 2 at row 14, column 13 would be left without room for its bulbs. So that cell has no bulb.
Nothing else can light the cell at row 14, column 14: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
Suppose the cell at row 1, column 9 had no bulb. That forces 6 more bulbs, and then the 2 at row 6, column 13 would be left without room for its bulbs. So it takes a bulb.
The 1 at row 3, column 8 still needs one bulb and has exactly one open side. It takes the bulb.
Nothing else can light the cell at row 6, column 6: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
The 1 at row 5, column 6 already has one bulb beside it. Its other open side gets no bulb.
The 1 at row 7, column 6 already has one bulb beside it. Its other open side gets no bulb.
Nothing else can light the cell at row 4, column 4: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
Only one cell can still light the cell at row 8, column 6: the one at row 8, column 5. The bulb goes there.
Only one cell can still light the cell at row 14, column 7: the one at row 14, column 6. The bulb goes there.
Suppose the cell at row 2, column 13 had no bulb. That forces four more bulbs, and then the 1 at row 7, column 14 would be left without room for its bulbs. So it takes a bulb.
The 2 at row 2, column 14 already has two bulbs beside it. Its other open side gets no bulb.
The 2 at row 6, column 13 still needs two bulbs and has exactly two open sides. Every one takes a bulb.
The 1 at row 7, column 14 already has one bulb beside it. Its other open side gets no bulb.
The 1 at row 7, column 13 still needs one bulb and has exactly one open side. It takes the bulb.
The 1 at row 8, column 10 still needs one bulb and has exactly one open side. It takes the bulb.
The 1 at row 5, column 11 still needs one bulb and has exactly one open side. It takes the bulb.
Nothing else can light the cell at row 5, column 9: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
Nothing else can light the cell at row 9, column 14: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
Suppose a bulb sat at row 12, column 11. That forces a bulb at row 13, column 13, and then the cell at row 14, column 12 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 12, column 12. That forces a bulb at row 13, column 13, and then the cell at row 14, column 11 would have nothing left to light it. So that cell has no bulb.
Nothing else can light the cell at row 14, column 12: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
The 2 at row 14, column 13 already has two bulbs beside it. Its other open side gets no bulb.
Only one cell can still light the cell at row 11, column 13: the one at row 12, column 13. The bulb goes there.
Only one cell can still light the cell at row 13, column 7: the one at row 13, column 11. The bulb goes there.