woordladders

Woordladders, or word ladders in English, are word puzzles in which one word is transformed into another by changing a single letter at each step. Each intermediate form must be a valid word, and the length of the words typically remains constant throughout the ladder. The objective is to produce a chain from a given starting word to a target word using as few steps as possible.

The concept was popularized by Lewis Carroll (Charles Dodgson) in the late 19th century; he published the puzzle in his book Doublets: A Ladder of Words (1879). Since then, word ladders have appeared in many languages and formats, with variations in allowed operations or word length. In Dutch-language contexts the form is commonly called woordladder or woordladders.

Solving word ladders involves using dictionaries and search methods to find valid intermediate words. Common techniques in computer solutions include breadth-first search to locate the shortest possible ladder between two words. These puzzles are used for language education, vocabulary development, and cognitive research on problem solving. A simple 4-letter example is: COLD -> CORD -> CARD -> WARD -> WARM.