"Earthquakes and Tsunamis Explained," ca. mid 17th century. On the outer edged of the circled dragon are written the months of the year. There is what appears to be a small sword just above and touching the dragon's head. Below this sword is written "kaname-ishi," (foundation stone). Inside the dragon are the "the 60 plus islands of Japan and the various foreign countries." The last line of text inside the dragon explains that all of these places should be regarded as existing above the dragon. In other words, the dragon resides under the earth. Normally, it is pinned down and made immobile by the deity of the Kashima Shrine, who presses down on a boulder (the kaname-ishi), which presses down on the dragon's head. The deity's sword is a substitute for the bolder. But sometimes the deity dozes or is otherwise distracted, and he lets up on the boulder. The dragon is thus able to wiggle around under the earth, which causes earthquakes. Now you know!