The full logical solve of the hard Light Up for September 8 to September 14, 2026, 14 × 14. 69 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 6, column 1 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 7, column 13 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 9, column 13 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 12, column 5 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 13, column 7 has no bulbs beside it, so none of its open sides can take one.
The 0 at row 13, column 10 has no bulbs beside it, so none of its open sides can take one.
Suppose a bulb sat at row 2, column 13. Its light closes the cells it reaches, and the 1 at row 1, column 14 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 13, column 2. Its light closes the cells it reaches, and the 1 at row 14, column 1 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 13, column 3. Its light closes the cells it reaches, and the 2 at row 14, column 4 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 13, column 13. Its light closes the cells it reaches, and the 2 at row 14, column 12 would be left without room for its bulbs. So that cell has no bulb.
Nothing else can light the cell at row 13, column 12: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
Suppose a bulb sat at row 1, column 2. Then the cell at row 2, column 3 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 3, column 2. Then the cell at row 2, column 3 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 4, column 11. That forces bulbs at row 6, column 12 and row 5, column 13, and then the 1 at row 6, column 13 would have too many bulbs. So that cell has no bulb.
Suppose the cell at row 5, column 13 had no bulb. That forces bulbs at row 5, column 14 and row 1, column 13, and then the 2 at row 4, column 13 would be left without room for its bulbs. So it takes a bulb.
The 1 at row 6, column 13 already has one bulb beside it. Its other open sides get no bulb.
Suppose a bulb sat at row 7, column 2. That forces bulbs at row 9, column 4 and row 8, column 5, and then the 1 at row 9, column 5 would have too many bulbs. So that cell has no bulb.
Suppose a bulb sat at row 4, column 3. That forces 8 more bulbs, and then the 2 at row 6, column 7 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 5, column 3. That forces 10 more bulbs, and then the 2 at row 6, column 7 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 7, column 3. That forces three more bulbs, and then the 1 at row 9, column 5 would have too many bulbs. So that cell has no bulb.
Suppose a bulb sat at row 7, column 5. That forces 5 more bulbs, and then the cell at row 12, column 2 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 9, column 1. That forces a bulb at row 8, column 3, and then the cell at row 10, column 2 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 9, column 3. That forces four more bulbs, and then the cell at row 10, column 2 would have nothing left to light it. So that cell has no 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 11, column 2 already has one bulb beside it. Its other open sides get no bulb.
Suppose a bulb sat at row 9, column 4. That forces bulbs at row 14, column 3 and row 13, column 1, and then the cell at row 12, column 2 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 10, column 4. That forces bulbs at row 14, column 3 and row 13, column 1, and then the cell at row 12, column 2 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 11, column 4. That forces bulbs at row 14, column 3 and row 13, column 1, and then the cell at row 12, column 2 would have nothing left to light it. So that cell has no bulb.
Only one cell can still light the cell at row 9, column 4: the one at row 13, column 4. The bulb goes there.
The 1 at row 14, column 1 still needs one bulb and has exactly one open side. It takes the bulb.
The 2 at row 14, column 4 still needs one bulb and has exactly one open side. It takes the bulb.
Only one cell can still light the cell at row 11, column 3: the one at row 12, column 3. The bulb goes there.
Nothing else can light the cell at row 8, column 1: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
The 1 at row 8, column 2 already has one bulb beside it. Its other open side gets no bulb.
The 2 at row 8, column 4 still needs two bulbs and has exactly two open sides. Every one takes a bulb.
The 1 at row 9, column 5 already has one bulb beside it. Its other open sides get no bulb.
The 1 at row 3, column 3 still needs one bulb and has exactly one open side. It takes the bulb.
The 1 at row 1, column 3 already has one bulb beside it. Its other open side gets no bulb.
Only one cell can still light the cell at row 1, column 4: the one at row 1, column 5. The bulb goes there.
Only one cell can still light the cell at row 8, column 3: the one at row 6, column 3. The bulb goes there.
The 2 at row 6, column 7 still needs two bulbs and has exactly two open sides. Every one takes a bulb.
The 1 at row 3, column 8 still needs one bulb and has exactly one open side. It takes the bulb.
The 1 at row 5, column 5 still needs one bulb and has exactly one open side. It takes the bulb.
The 2 at row 5, column 12 still needs one bulb and has exactly one open side. It takes the bulb.
The 2 at row 4, column 13 already has two bulbs beside it. Its other open sides get no bulb.
The 2 at row 6, column 10 still needs two bulbs and has exactly two open sides. Every one takes a bulb.
The 2 at row 7, column 8 still needs one bulb and has exactly one open side. It takes the bulb.
Only one cell can still light the cell at row 1, column 2: the one at row 5, column 2. The bulb goes there.
Only one cell can still light the cell at row 1, column 8: the one at row 1, column 10. The bulb goes there.
Nothing else can light the cell at row 1, column 13: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.
The 1 at row 1, column 14 already has one bulb beside it. Its other open side gets no bulb.
Only one cell can still light the cell at row 2, column 14: the one at row 3, column 14. The bulb goes there.
Nothing else can light the cell at row 3, column 1: 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 14, column 10: the one at row 14, column 11. The bulb goes there.
The 2 at row 14, column 12 already has two bulbs beside it. Its other open side gets no bulb.
Suppose a bulb sat at row 10, column 7. Its light closes the cells it reaches, and the 2 at row 9, column 8 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 11, column 11. Its light closes the cells it reaches, and the 1 at row 10, column 10 would be left without room for its bulbs. So that cell has no bulb.
Suppose a bulb sat at row 2, column 6. That forces three more bulbs, and then the cell at row 7, column 12 would have nothing left to light it. So that cell has no bulb.
Suppose a bulb sat at row 3, column 6. That forces three more bulbs, and then the cell at row 7, column 12 would have nothing left to light it. So that cell has no bulb.
Suppose the cell at row 9, column 7 had no bulb. That forces bulbs at row 10, column 8 and row 11, column 6, and then the cell at row 9, column 7 would have nothing left to light it. So it takes a bulb.
The 2 at row 9, column 8 already has two bulbs beside it. Its other open side gets no bulb.
Only one cell can still light the cell at row 10, column 5: the one at row 10, column 6. The bulb goes there.
Suppose a bulb sat at row 10, column 11. That forces a bulb at row 11, column 12, and then the cell at row 14, column 13 would have nothing left to light it. So that cell has no bulb.
The 1 at row 10, column 10 still needs one bulb and has exactly one open side. It takes the bulb.
Only one cell can still light the cell at row 7, column 12: the one at row 10, column 12. The bulb goes there.
Only one cell can still light the cell at row 13, column 8: the one at row 12, column 8. The bulb goes there.
The 2 at row 12, column 12 still needs one bulb and has exactly one open side. It takes the bulb.
Nothing else can light the cell at row 9, column 11: every cell that sees it is lit, dotted or behind a black cell. It needs its own bulb.