Japan Sailing Maps are a group of sea charts made with Western measurement techniques and belong to the type called portolan maps with many bearing lines. They were independently produced by Japanese, covering only the Japanese Archipelago and surrounding areas for domestic marine transportation purposes. The existing versions are few, especially ones drawn on parchment, only two of which survived: one is in Tokyo National Museum, and the other is in Mitsui Bunko in Tokyo.
This map is colored with red and deep blue pigments on parchment colored with Paris white. The area covers Honshū, Shikoku, Kyūshū, and their outlying islands, but does not include Ezo (Hokkaido). The coastal areas contain the areas of shallows and some other information necessary for sailing. The names of places include “Suruga” with an annotation, as well as other important ones, such as Edo, Kyō, and Osaka. This confirms that the year of production of this map is later than when Tokugawa Ieyasu moved to Sunpu, the capital of Suruga [Keichō 12 (1607)]. Apart from this, most of the names of places are in western Japan, while there is none in the eastern and northwestern parts of the country. Since most of the names of the harbors and ports began to be used in the medieval period, this map was produced probably not very long after Keichō 12.