Nonograms

Nonograms, also known as picture crosswords, picross, griddlers, and other names, are logic puzzles that use a grid and numeric clues to reveal a hidden picture. The goal is to fill certain cells in the grid so that the resulting pattern matches all provided clues.

Each row and column carries a clue: a sequence of numbers that indicate the lengths of consecutive filled squares in that line. The numbers must be filled in the given order, and at least one empty cell must separate successive blocks. By applying these clues, solvers determine which cells are filled and which remain blank.

Solving methods rely on logical deduction. Start with the total length of runs and the line length to infer guaranteed filled or empty cells, use overlapping possibilities to narrow down which cells could be filled, and cross-check between intersecting rows and columns. Some puzzles can be completed purely by logic, while others—especially larger grids—may require trial-and-error or backtracking techniques.

Variants and accessibility: Most standard puzzles are monochrome, but color nonograms use multiple colors to represent different runs, increasing difficulty. Puzzles range from small grids (a few by a few) to large, complex layouts. They are available in print and digitally, including computer software and mobile apps, often offering hints, auto-solve, and difficulty settings.

History and usage: The puzzle type originated in Japan in the late 20th century and has since gained global popularity under names such as nonograms, picross, and griddlers. They are used for entertainment, cognitive exercise, and educational purposes related to logic and planning.