QZBrain Journal
What Is a Nonogram? A Beginner's Guide to Picross
A nonogram is a grid puzzle where numbers along the edges tell you which squares to fill in. When you solve it correctly, the filled squares form a small picture. No guessing is required: every move can be worked out by pure logic.
You may have seen them under other names. Picross, Griddlers, Hanjie, Paint by Numbers, and Japanese crosswords all describe the same puzzle. This guide explains how the clues work, walks through the core solving moves, and shows why nonograms make such a calm, satisfying logic puzzle.
Play free nonograms → Open one in your browser and follow along as you read.
What the numbers actually mean
Each row has clues on its left. Each column has clues on top. The numbers tell you the lengths of the filled groups in that line, in order.
A clue of 3 means there is one unbroken run of exactly three filled squares somewhere in that line. A clue of 1 4 means a run of one filled square, then a gap of at least one empty square, then a run of four filled squares, in that left-to-right or top-to-bottom order. The gaps between runs can be any size of one or more, but the runs themselves are exact.
- A single number is the length of one filled block in that line.
- Several numbers are several blocks, in order, separated by at least one empty square.
- The order of the numbers matches the order of the blocks along the line.
- A clue of 0, or a blank clue, means the whole line stays empty.
The numbers are exact run lengths in order, separated by gaps of one or more empty squares.
The two marks you make
Solving a nonogram comes down to two actions. You fill a square when you are certain it belongs to a run, and you mark a square with an X when you are certain it stays empty.
Those X marks are not decoration. They are deductions. Every empty square you confirm narrows down where the remaining runs can sit, which often unlocks the next fill. Beginners who skip the X's tend to get stuck; solvers who mark every confirmed empty square keep finding their next move.
Start with the overlap
The most useful beginner technique is overlap. When a clue is large relative to the length of its line, the run cannot avoid certain squares no matter where you slide it, so those squares are guaranteed to be filled.
Picture a row that is 5 squares wide with a single clue of 4. Push the run as far left as it goes and it covers squares 1, 2, 3, 4. Push it as far right as it goes and it covers squares 2, 3, 4, 5. Squares 2, 3, and 4 are filled in both extremes, so they must be filled. You can fill them immediately, even though you do not yet know the exact position of the run.
The trick: subtract the clue from the line length to get the wiggle room. Here, 5 minus 4 is 1 square of wiggle. Any part of the run longer than that wiggle is locked in place. A clue of 4 with 1 square of wiggle has 4 minus 1, or 3, locked squares. The bigger the clue relative to the space, the more you can fill on the very first pass.
Then work the edges
Edges are the other place easy deductions hide. If the first clue in a row is 3 and you already know the very first square is filled, then the next two squares must be filled too, and the square right after the run must be empty. Mark those two extra fills, then drop an X on the square that closes the run.
This works because a run cannot be longer than its clue. The moment you anchor one end of a block, you can count out its full length and cap it with an X. Edge logic and overlap logic feed each other: a fill from overlap often anchors a run, and capping that run reveals an empty square that helps a crossing line.
A short worked example
Imagine a 5x5 grid. Take the top row with the clue 5. The run is exactly as long as the row, so there is zero wiggle room. Fill all five squares of the top row with no guessing at all. Clues that equal the line length are always your easiest free wins, so scan for them first.
Now take a column whose clue is 1 1. That means two single filled squares with at least one gap between them, somewhere in five squares. You cannot place them yet, so leave that column alone and come back once a crossing row has filled or X'd a square in it. Nonograms reward patience: a line you cannot solve now usually becomes obvious after you have worked a few crossing lines.
Keep cycling through rows and columns. Each fill or X you place in one direction is new information for the lines that cross it. A clue that looked ambiguous a minute ago turns into a forced move once a single crossing square is settled. That ripple is the whole game.
- Scan for clues equal to the line length and fill them outright.
- Apply overlap to every long clue to lock in guaranteed squares.
- Anchor runs at the edges and cap them with X's.
- Re-check crossing lines after every new mark, and repeat until the picture appears.
Why nonograms feel calm
Good nonograms have exactly one solution that can be reached without guessing. That changes the feel of the puzzle. There is no luck and no dead end you could not have avoided. If you are stuck, the next move is on the board waiting to be deduced, which keeps the experience low-pressure rather than frantic.
The work itself is quiet and repetitive in a good way. You scan a line, count, deduce, and mark. Many people find that loop genuinely relaxing, the same way a Sudoku grid can be. It is steady attention without a ticking clock pushing on you.
We will be honest about what that does for you, though. Solving puzzles makes you better at solving puzzles, and it is an enjoyable way to spend focused attention, but there is no evidence it raises general intelligence or rewires your brain. Enjoy nonograms because they are a good logic puzzle, not because they promise a smarter you. We cover that distinction in detail in our guide to realistic expectations.
Brain games vs. brain training → If you want the honest version of what puzzles can and cannot do.
How to get started
Begin with small grids, around 5x5 or 10x10, until the overlap and edge moves feel automatic. Use the X marks generously, because confirmed empty squares are what keep the deductions flowing. When you want a fresh one each day, a daily nonogram gives you a single new puzzle to work through without hunting for something to play.
Play the daily nonogram → A new picture-logic puzzle every day, free and in your browser.
Train with QZBrain
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Frequently asked questions
Is a nonogram the same as Picross?
Yes. Picross, Griddlers, Hanjie, Paint by Numbers, and Japanese crosswords are all names for the same picture-logic puzzle. Picross became popular through Nintendo's series, but the rules are identical to any nonogram.
Do nonograms require guessing?
A well-made nonogram has exactly one solution that you can reach through pure logic, with no guessing. If you feel stuck, the next move is usually a deduction you have not spotted yet. Mark every confirmed empty square with an X and re-check the crossing lines.
What do the X marks mean?
An X marks a square you have proven must stay empty. It is a deduction, not a guess. Tracking empty squares is just as important as filling squares, because each X narrows down where the remaining runs can sit and often unlocks your next fill.
What size nonogram should a beginner start with?
Start with 5x5 or 10x10 grids. They are small enough to hold in your head while you learn the overlap and edge techniques, and you will finish them quickly enough to build momentum before moving up to larger pictures.
QZBrain is a general wellness and brain-training product for everyday cognitive exercise and entertainment. This article is general information, not medical advice, and is not intended to diagnose, treat, cure, or prevent any condition.