How to Solve Nonograms: Rules, Tips and Strategies for Beginners
A nonogram — also called a picross, griddler or hanjie — looks like an empty grid with numbers around the edges, and the numbers are the whole puzzle. Each row and column has a list of clues that tells you exactly where the filled squares go, and when you fill them all in, a picture appears. It's pure logic, no guessing, and every puzzle has exactly one solution. Here are the rules and the strategies that make them click.
The rules in one minute
The numbers at the start of each row and column are clues, read from the edge toward the grid. Each clue is the length of one block of filled squares in that line, and the blocks appear in order with at least one empty square between them. A clue of “2 1” means: a block of 2 filled squares, then a gap, then a block of 1 — never 1 2, never 2 1 touching. Your job is to decide which squares are filled and which are definitely empty, until the whole picture is revealed. Every puzzle on our nonogram maker is guaranteed to have exactly one solution, so logic alone always gets you there.
1. Learn the overlap trick — the heart of nonograms
When a clue number is bigger than half the line, some of its squares are forced no matter where the block sits. Picture a row of 10 squares with the clue “8”. Slide an 8-square block along the row: at the left edge it covers squares 1–8, at the right edge it covers 3–10. The squares it covers in both positions — squares 3 through 8 — must be filled in every solution. The rule: for a single clue c on a line of length n, the middle 2c − n squares are guaranteed filled. A clue of 8 on a 10-wide row fills 6 squares instantly; a clue of 3 on a 5-wide row fills 1. This one trick solves most of the first few moves.
2. Start with the longest clues
The bigger the clue, the more squares it forces, so sweep the grid for the longest numbers first. On our nonogram generator, Easy puzzles are 8×8 with few long runs, while Hard 12×12 grids load you up with bigger numbers and more combinations — exactly the progression to practice with. Fill in every forced square from the long clues before touching anything else; the picture builds outward from those anchors.
3. Mark the empty squares with ×
Nonograms are as much about what can't be filled as what can. When a block's position is pinned at one end of its line — for example, a clue of 8 on a 10-wide row that you know starts at square 1 — the squares beyond it are definitely empty. Mark them with an × (on screen, right-click or Shift+click, or tap the Mark × button). Every × you place narrows the possible positions of the remaining blocks, which forces new squares elsewhere. Empty squares are clues too.
4. Add the clue numbers up
Every line has a minimum length: the sum of its clues, plus one empty square between each pair of blocks. If a line's clues add up to 6 with 3 blocks, its minimum length is 6 + 2 = 8. Compare that to the line's actual length — the difference is how many “extra” empty squares can be distributed, and that tells you how much freedom the blocks have. When the minimum equals the length, the line is completely determined: fill the blocks and mark every gap empty. When the difference is small, the blocks are nearly pinned and the overlap trick fills the rest.
5. Work rows against columns
A filled square is simultaneously part of a row clue and a column clue. After you fill a square from a row's logic, check what it means for the column: it may pin a block in that column, which then forces more squares in the rows it crosses. This back-and-forth is where nonograms really come alive — one forced square cascades through the whole grid. If you're ever stuck, stop and look at a column whose clue you haven't touched yet.
6. Use the edge rows and columns first
Lines at the edge of the grid behave like ordinary lines, but the blocks in them can't be pushed outward, which often pins them faster. Clearing the border first gives you a frame of known squares and empties that the inner rows and columns have to respect. Combined with the overlap trick, the outside ring of a puzzle is usually the easiest part — and the best place to warm up.
7. Never guess
Because every nonogram has exactly one solution, guessing is never required — and it's the fastest way to get lost. If you're stuck, you've missed a forced move, not a hidden one. Re-check the lines with the biggest clues, recount the gaps between blocks, and look for ×-squares you haven't placed. On screen, the nonogram maker's Check button highlights anything that doesn't match the solution, which is a great way to see exactly which line you misread.
Practice with a printable nonogram
Nonograms build skill fast because every puzzle is a fresh picture. Generate one in seconds on the nonogram generator — start with an 8×8 Easy puzzle, print it or solve on screen with the Fill and Mark × modes, and work up to 12×12 Hard. If you enjoy this kind of picture logic, you'll probably love kakuro, its number-based cousin — and our difficulty guide explains how the levels on every tool here actually differ.