Picross

Picross, also known as Nonograms, Griddlers, or Hanjie, is a logic puzzle played on a grid. Each row and column carries a series of numbers that indicate the lengths of consecutive filled blocks in that line. For example, a row clue "3 1" means there is a run of three filled cells, followed by at least one empty cell, then a single filled cell. By applying these clues to all lines, players shade cells to reveal a hidden picture. Solving is typically done by deduction rather than guesswork.

Clues determine shading and empty spaces in a consistent order. Solvers often use pencil marks to track possibilities, look for forced placements, and use cross-checks between intersecting lines. Puzzles range in size from small 5x5 grids to large 25x25 or bigger, and most have a unique solution.

Originating in Japan in the 1980s, Picross-type puzzles were popularized by publishers such as Nikoli. The puzzle exists under several names: Nonograms, Picross, Hanjie, and Griddlers. The brand name Picross is used by Nintendo for a long-running video game series beginning on the Game Boy, while Nonogram is the generic term.

Today Picross puzzles appear in newspapers and puzzle books, in dedicated apps for mobile devices, and as features in video games. They are widely used for entertainment and as a tool to exercise logical thinking and pattern recognition. The basic mechanic remains the same across media, though digital versions often offer features such as shading previews and automatic pencil marks.