The rule in one sentence
Transform the start into the target by changing exactly one letter per step, while keeping every intermediate rung a valid word of the same length.
A ladder is not solved by rearranging letters, inserting a character, or changing two positions at once. Each accepted rung differs from the previous word at one position only.
Compare both endpoints
Mark the positions that already match. A matching letter is useful, but it is not sacred: changing it temporarily may open a much shorter route.
Then list familiar one-letter neighbors of both the start and target. The target often has fewer obvious neighbors, so working backward can expose the final rung.
Preserve flexibility
Common vowel patterns and productive endings usually have more neighbors than rare clusters. Prefer a middle word that offers several next moves rather than one that merely looks closer to the target.
If you hit a dead end, return to the last flexible rung and change a different position.
A small example
To move from COLD to WARM, one possible ladder is COLD → CORD → CARD → WARD → WARM. Each step changes exactly one position, and every rung remains a four-letter word. Another valid ladder may exist; a puzzle accepts the route, not one memorized solution.
What par means
Par is the length of a verified shortest route. Lexora uses breadth-first search over its accepted dictionary before publishing a level. That gives the minimum number of moves, while still allowing alternative paths that obey the limit.
Shortest-path checklist
- List target neighbors as well as start neighbors.
- Look for a bridge pattern shared by both sides.
- Avoid rare letter combinations that have few valid neighbors.
- Do not protect matching letters when a temporary detour opens the route.
- Use the move counter to decide when to backtrack.