How to start a nonogram
The hardest part of a blank nonogram is the very first square. The trick is that you don't start by guessing anywhere — you start where the clues leave you no choice. This guide covers the handful of first moves that crack almost any puzzle open, using a 5-wide line for every example. If you're not yet sure what the clues mean, read the rules first.
1. Fill the lines you can complete immediately
Before anything clever, scan for lines that are already fully decided. The obvious one is a clue equal to the line's length — a 5 on a five-wide row fills the whole row. Less obvious, but just as certain: when the clue's numbers plus the gaps between them add up to exactly the line length, the line has only one arrangement.
These "free" lines are the best possible start, because every square you fill in one direction becomes a clue you can cross-check in the other. Always sweep every row and column for them first.
When the numbers add up exactly
2 + gap + 2 = 5. The line is forced: filled, filled, empty (✕), filled, filled.
1 + gap + 3 = 5, also exact: one square, a gap, then a run of three.
2. Use the overlap trick on long clues
This is the single most useful technique for getting started. When a run is long relative to the line, it can't move very far — and the squares it covers no matter where it sits are guaranteed filled. Slide the run as far left as it goes, then as far right; any square filled in both positions is certain.
The longer the clue, the bigger the overlap. A run of 4 in a 5-wide line pins down three squares; a run of 3 pins down just the center one. Even one or two forced squares from overlap are often enough to unlock the crossing lines.
The overlap trick, step by step
A clue of 5 on a 5-wide line fills every square — the simplest "free" line.
A run of 4 can only shift by one square, so the middle three are always filled.
A run of 3 overlaps in just one square — the center. Shorter clues give less certainty.
3. Mark the empty squares, not just the filled ones
Solving a nonogram is as much about proving squares empty as filling them. Once a line is finished, every remaining square in it is definitely empty — mark each with an ✕. Those marks aren't decoration: an ✕ in a crossing line tells you a run can't sit there, which frequently forces the next deduction. Players who skip marking empties tend to stall much sooner.
4. Build only on what's certain
A proper nonogram never requires a guess, so don't make one. Every square you fill or cross should follow from a clue with no doubt attached. If you're tempted to "try" a square and see what happens, stop and look for a line where the answer is forced instead — it's almost always there. Guessing is how mistakes creep in, and a single wrong square can quietly break the whole picture.
5. Keep switching between rows and columns
Progress comes from the back-and-forth. Fill what you can in the rows, then turn to the columns and use those new squares as fresh clues, then go back. A puzzle that looks stuck from the rows' point of view is often one column away from opening up again. When you're unsure where to look next, switch direction.