Kazutaka Unno (海野一隆):
Maps of Japan used in prayer rites or as charms
Cartographica Helvetica 10 (1994) 20–23
Early maps of Japan show the coastline and the boundary lines between provinces by means of smooth curves. As a common characteristics, they all show the main routes leading from the province of Yamashiro, where Japan's capital Kyoto has been ever since 794.
More than half of these maps have an inscription indicating Gyōki (行基) (668–749), a Buddhist priest of the Nara period, as the author.
Inscriptions in Buddhist documents also mention that Japan is shaped like the point of a 'tokko'. Therefore all maps had to show the eastern end of Honshu accordingly. The 'tokko' is a short copper or iron rod which was originally a weapon for self-defense used by Indian priests and later became a Buddhistic symbol of strength. Oddly enough, the maps of Japan were oriented in an almost exact east-west direction. Such maps were used in Buddhist ceremonies.
From the beginning of the 17th century, Gyōki-type maps were being printed and became widely distributed among the public. One of these printed maps is oriented to the east and has a dragon drawn around the archipelago. This type of Japanese map is a combination of a good-luck charm (to ward off earthquakes) and a fortune-teller. Later on the dragon was slowly replaced by the 'namazu' (cathfish) which then was blamed for earthquakes.