Seri and Mawari Butai
The revolving stage (mawari butai) is a circular platform 7.3 meters in diameter, in the center of the stage. A circle is cut from the center of the flooring, and there is a mechanism underneath it to turn the stage. The revolving stage can turn 360 degrees, and was first developed for Kabuki theaters. It is used for scene changes and other effects. Modern theaters use electricity to rotate the stage, but at Kanamaruza it is still people powered.
Beneath the revolving stage is a space called naraku, with four poles and thirty-six stone footholds arranged on the earthen floor. Pushing the poles, the movers move from one foothold to the next to rotate the central stage. Between the stage above and its frame are wooden rollers (or roller bearings). There are twenty-six sets, each with three rollers inside, and these are used to facilitate the rotating of the stage. In 2010, the wooden rollers were recognized as a Mechanical Engineering Heritage by the Japan Society of Mechanical Engineers.
Within the revolving stage, there is a cutout lift or another trap door (seri) (0.9 m x 1.9 m). This is a rectangular platform that operates as a lift, descending into the naraku below and rising again to the stage level. The use of the seri is yet another way to add dramatic tension to the play. This too is human-powered.