Old Konpira Oshibai Kabuki Theater (ʻKanamaruzaʼ) revolving stage and its slewing mechanism

The Old Konpira Oshibai Kabuki Theater is the oldest existing wooden theater playhouse building in Japan, built in 1835, and is still in service today. The revolving stage has a total weight of two to three tons and a diameter of 7.3 meters. To rotate it lightly and quietly with the force of four persons, it includes a mechanism called a rotary top. The rotary top is comparable to present-day roller bearings, wherein 78 wooden rollers with a diameter of 120 millimeters are arranged in a circular shape. The revolving mechanism can be referred to as the primogenitor of today’s revolution seat bearing and shows the excellence in mechanical techniques of Japan in the Edo period. In addition, it is a valuable heritage in terms of technology and culture as a mechanical device that contributed to the development of traditional arts in Japan.