Structural analysis of traditional Chinese puzzle boxes

Abstract. A puzzle box (also known as a trick box) is a box that may be opened by solving some obstacles originally designed by the manufacturer. Some puzzle boxes may be opened with a few moves, while others call for problem-solving and decision-making skills to unlock all the blocks inside the box. Puzzle boxes have existed throughout the ancient ages of the east and west, and their popularity has grown significantly since the 17th century. Chinese puzzle boxes are classified into four types based on the first movement during the initial opening stage: whole-box rotation, mechanical-member sliding, mechanical-member rotation, and pin removal. Since the topological structure of the puzzle box changes during the opening process, it falls under the category of the variable topology mechanism. This study proposes a graphical method for systematically analyzing traditional Chinese puzzle boxes. It discusses the structural characteristics of puzzle boxes and applies line graphs to explain the variable topological structures involved in the opening process. The paper presents four different types of puzzle boxes as examples of applying the proposed method and illustrating the opening processes of the puzzle boxes. Traditional Chinese puzzle boxes are diverse and creative, displaying the skilled craftsmanship of ancient artisans. A series of puzzle boxed can be further systematically synthesized through the atlas of line graphs and generalized chains.