Klotski (Huarong Dao) Solver

Klotski, known in Chinese as Huarong Dao, is a sliding-block puzzle on a 4 by 5 board. The goal is to move the large 2 by 2 block down to the exit at the bottom centre. This page solves the classic layouts by breadth-first search, shows the fewest moves and lets you step through the whole solution one move at a time.