New to Light Up? Learn the three rules on a 7×7, then get used to the two things that drive every puzzle: the numbers, which tell you where bulbs must and mustn’t go, and the light, which rules out a whole row and column with every bulb. This page puts the guides in that order, with six small warm-ups to check yourself before you move up a size.
Your path, in order
- Learn the rules. The Light Up rules page solves the game’s first level step by step. The one idea to take away: a bulb lights its row and column until a black square stops it, and no bulb may light another.
- Start every puzzle with the 0s, and the numbers with just enough room beside them.
- Dot every square a bulb lights. It’s most of the work.
- Look for dark squares with only one way left to be lit.
- Do the warm-ups below. Six small grids, each practising an idea from the guides.
- Learn the other techniques. How to solve Light Up covers all seven.
- When a puzzle goes wrong, read the six common mistakes. The big one is placing a bulb before it’s certain.
- Move up a size when you’re ready (see below).
Warm-up: six small puzzles
Each has exactly one solution, and each needs one more idea than the one before. Solve it, then open the answer.
1. A number with just enough room
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Start with the 2 on the left edge. The 1 beside it is a black square, so the 2 has only two white squares, above and below it, and both get bulbs. Their light rules out the rest of the top row. The 1 beside the 2 then has only the square to its right left, and the 1 in row 3 only the square below it: a bulb in each.
2. A 3 on the edge
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The 3 on the top edge has exactly three squares beside it, so all three get bulbs. Two of them touch the 2 in row 2, which now has all its bulbs: its other squares get dots. The 1 in row 2, column 1 is left with only the square below it. Last, the 2 at the bottom needs both squares still open beside it.
3. Boxed-in squares
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The 0 dots its two neighbours. Now look at the centre square: numbers wall it in on all four sides, so nothing else can light it. It needs a bulb of its own. So does row 4, column 2, walled in by two numbers and the 0’s dots. From there the numbers finish it.
4. A number’s corner
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The two 0s dot their neighbours, the 2 in the corner needs both its squares, and the 1 on the right edge has only the square above it. Now the 1 in row 2, column 2: its bulb must go above it or to its right. A bulb in row 1, column 3, diagonal to the 1, would light both, so no bulb there. The top-left corner can then only be lit from row 1, column 2, which takes the 1’s bulb, and the last dark square is lit from row 2, column 4.
5. Leaving a square dark
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The 0 dots its neighbours, the 3 on the top edge needs all three of its squares, and the two 1s each have one square left. Then look at row 5, column 5, beside the 0: it can’t light itself, and only two squares can still light it, the one above it and the one to its right. A bulb in row 4, column 6 would light both, leaving it dark, so no bulb there. That leaves the two squares each needing a bulb of their own.
6. Everything together
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The 0 dots its neighbours, which boxes in the bottom-right corner: a bulb of its own, which satisfies the 1 beside it. The 2 at the top needs two of its three squares, so no bulb in row 2, column 1, diagonal to it, where a bulb would light two of them. The 2 on the left edge then needs both its squares, and the top 2 gets its bulbs. Last, row 5, column 5 can only be lit from row 2, column 5 or row 5, column 4. A bulb in row 2, column 4 would light both, so no bulb there, and each of the two gets a bulb of its own.
When to move up a size
You’re ready for Medium (10×10) when you can finish Easy levels without guessing, and you dot every square a bulb lights without thinking about it. The bigger grids lean on number corners: needed on 19 of the 50 Easy levels, 27 Medium and 49 Hard. On Hard (12×12), every level also needs what-if.