Nonogram Techniques

Six techniques solve every Nonogram on PeerPuzzles. Learn them in this order: the first five are quick rules you can apply at a glance, and the sixth, listing every arrangement, is the slow, sure method for when the quick ones run out. Each page shows its technique on the same 10×10 puzzle from the game, at the moment it’s first needed, so you can follow one solve from page to page.

The 10×10 every technique page follows. It takes 49 steps and needs all six techniques.

How many of the game’s puzzles need each one, out of 100 at each size:

Technique	5×5	10×10	15×15
Finished lines	100	100	100
Overlap	100	100	100
Edges	9	52	97
Out of reach	3	28	81
Small gaps	0	0	21
Every arrangement	7	22	70

“Needs” means nothing simpler would do at that point in the solve. For all six in one place, with another worked puzzle, see how to solve Nonograms.

Guides

Nonogram Finished Lines: Cross Out the RestWhen a Nonogram line already matches its clue, every other square in it is empty. Why crossing them out at once matters, with a real example.
Nonogram Overlap: Fill What Every Position SharesSlide a Nonogram line's blocks as far left as they go, then as far right: squares a block covers both times are filled. The slack rule, with real examples.
Nonogram Edges: A Filled Square Near the EndA filled square close to the start of a Nonogram line must belong to the first block, so the block reaches past it. With a real example from the game.
Nonogram Out of Reach: Squares No Block Can Get ToPack a Nonogram line's blocks left and right: any square no block can reach is empty. How crosses push blocks out of reach, with a real example.
Nonogram Small Gaps: Too Short for Any BlockA stretch of open squares between crosses that's shorter than the smallest block can't hold one, so it's empty. A quick rule for big Nonograms.
Nonogram Line Solving: List Every ArrangementWhen the quick Nonogram rules find nothing, list every way a line's blocks can still fit: squares the same in all of them are settled. With a real example.