diagramless

Diagramless crosswords are a form of crossword puzzle in which the grid is not provided to the solver. Instead, the clues are given without a diagram, or with only partial information, and the solver must determine both the placement of words and the positions of the black squares. The result is a grid whose shape is discovered as the puzzle is solved. Sizes are commonly 15 by 15, but other dimensions are seen.

The origin of diagramless crosswords dates to the early 20th century in American puzzle culture, as enthusiasts experimented with removing the diagram to increase difficulty. The term diagramless describes puzzles that do not reveal the grid in advance; several early publishers featured them, and they have remained a niche within the broader crossword hobby.

In a typical diagramless puzzle, clues are presented for Across and Down entries, often with standard enumerations to indicate word lengths, but without a diagram. Solvers deduce the grid by fitting answers in a way that satisfies both directions; practice involves building the grid step by step, using long thematic answers to anchor crossing letters, and applying crossword constraints to determine black-square placements. Pencil and scratch work is common; some solvers begin with the longest answers or with symmetrical patterns if the puzzle uses symmetry.

Today diagramless puzzles appear in specialized puzzle books, magazines, and online communities. They are valued for testing a solver’s ability to infer structure rather than rely on a provided diagram, and they can be used as a meta-challenge or educational exercise in grid design as well as solving.