How to solve any nonogram: 12 techniques, each with a playable puzzle
Every lesson has a diagram, a plain explanation and a small grid built so that the technique is needed. Press "Show the step" if you are stuck, and the page points at the next move.
- 1Completing a lineCount the boxes, then fill or cross out the leftovers
- 2Simple boxesSlide the block left, then right, and keep the shared squares
- 3Counting the slackShrink the line to what is still open, then recount
- 4PunctuatingA block that cannot grow needs a cross on each side
- 5Simple spacesUse the reach of a block to find squares that are out of range
- 6GlueA box close to the border cannot belong to anything but the first run
- 7MercuryThe run cannot fit before the box, so the end square is empty
- 8ForcingCrosses shrink the room, and blocks have to move to what is left
- 9Joining and splittingFill a one-square gap that must close, or cross one that must stay open
- 10Cross-referencingWork one line at a time, and change direction every time you learn something
- 11ContradictionsWhen every line rule is spent, test one square and look for a break
- 12Deeper searchChain several pencil proofs, and know what comes after
How this series works
Nonograms, also called picross, are solved by logic and never by guessing. The lessons run from easy to hard. The first three are arithmetic, the next six use the boxes and crosses you already have, the tenth shows how rows and columns feed each other, and the last two are the tools for the rare grid that still will not move.
Each practice grid was checked by a solver that is only allowed to use named rules. For the rule lessons, we confirmed it solves the grid with every rule and gets stuck when the lesson rule is taken away. That is how we know the grid really needs the technique, and each lesson page prints the numbers.
Solved step by step
Alongside the lessons, we take past daily puzzles and solve them on the page, one line at a time, naming the technique behind each move. Each one links to the puzzle so you can try it first. They are always puzzles that are already in the archive, so they never give away today's answer.
Nonograms solved step by step (4 so far).
GRIDS: daily nonogram
GRIDS gives you one picture a day, in 5x5 and 7x7 sizes made for phones.
Play GRIDSQuestions
In what order should I learn the techniques?
Follow the numbers. Lessons 1 to 3 are counting, lessons 4 to 9 use crosses and boxes you already have, lesson 10 ties rows and columns together, and lessons 11 and 12 are the last resort when nothing else works.
Are the practice puzzles the daily puzzle?
No. Each lesson has its own small grid, built so that the lesson technique is needed. They never show a daily or future puzzle.
What does "show the step" do?
It reads the squares you have marked, finds the next move that uses the lesson technique, highlights the line and says why. If that technique has no move open yet, it says so and shows another. If a mark is wrong it highlights the line that holds it.
Does the page remember my progress?
Yes, in your own browser. Each practice grid keeps your marks if you reload, and Undo steps back through them.
Where do the technique names come from?
Mostly from the Wikipedia article on nonograms, which names simple boxes, simple spaces, forcing, glue, joining and splitting, punctuating and mercury. The explanations, diagrams and puzzles on these pages are ours.