20×20 Nonogram puzzles
How to play nonograms
A nonogram is a picture hidden in a grid. The numbers beside each row and above each column tell you which cells to fill in. Fill the right cells and the picture appears.
Reading the clues
Each number is a run of filled cells in that row or column, in order. The clue 3 1 means a run of three filled cells, then at least one empty cell, then one more filled cell. A 0 means the whole line is empty.
Filling and marking
Tap a cell to fill it. When you know a cell must stay empty, mark it with an X so you don’t have to work it out again. You can drag across a row or column to fill several cells at once.
Solving without guessing
Every puzzle on this site has exactly one solution, and you can always reach it by logic alone. Start with the lines whose clues are large compared with the grid: in a 10-cell row, a clue of 8 must cover the middle six cells wherever it starts.
Also known as
Nonograms are also called Hanjie, Paint by Numbers, Griddlers or Picross, and in Japan Oekaki Logic.