Ricochet Robots is Solved

Abstract

Ricochet Robots is a puzzle game published by Rio Grande Games and designed by Alex Randolph. Given a starting position with four robots on a board and a target space, the objective is to move the active robot to the target space in as few moves as possible. In this note, we announce that Ricochet Robots is strongly solved, i.e., a solution with the minimum number of moves has been computed for all possible starting positions. We solved the game using a complete retrograde analysis on all one trillion (10¹²) positions on a multi-core personal computer over a period of about a week.