黒潮と日本人の遭遇史 （第三部） 追補論考

Abstract

Since ancient times the South China Sea used to be the international access sea to China for envoy and trade ships from southern and central Asia and Europe. Searching ancient drifting records about wrecked foreigners who reached Japan, the author has found several illustrations that show transferred driftings from northeastward or eastward winds and currents in the South China Sea to the Kuroshio. They are examined in the light of modern oceanography and meteorology knowledge. These transferred driftings must have contributed to direct introduction of various foreign cultures to local places in Japan. Next, three typical routes of Kentoshi, the Japanese envoy to China in the Tang Dynasty, are illustrated together with circles of the visible horizon from the top of main islands in the East China Sea, and driftings of wrecked ships of the Kentoshi in 753-754 are examined by considering winds and the Kuroshio stream. In November, 748 Ganjin, Chinese Buddhist naturalized as a Japanese archbishop later, failed to reach Japan and drifted to Hainan Island by a violent wind. The 14 days recorded as the drifting period is too short to carry the boat to the Island even if the wind was very strong. The earliest mentions of the Kuroshio stream by the Japanese in provincial maps of Ryukyu (Bakufu, 1646-47, 1702) and of the term Kurose Gawa in Mori's map (1752) are examined. Regarding the problem how people in the Edo period (1603-1867) understood the Kuroshio, three topics are discussed. (1) Toward the end of the 18th century, a strange tale of red tides was believed in Hachijo Island, to carry wrecked boats to the boundless ocean. It is similar to contemporary legends of the Kuroshio, regarded as a terminal current of no return. (2) The view of fragmental currents might interrupt the recognition of the Kuroshio as a long continuous current in the Edo period. The view seems to be latent in current charts by Fuglister (1955) and in Sailing Directory for the Southeast Coast of Honshu (Japan Hydrographic Department, 1949). (3) Toward the end of the Edo period a ship's journal frankly recognized difficulties in perceiving of the Kuroshio stream. This demonstrative attitude shows the Japanese at that time slowly reaching a modernized understanding of the Kuroshio. A chronological table for the history of encounters with the Kuroshio is compiled.