1997 年 17 巻 p. 49-56
lzuniozaki Town in Niigata Prefecture is a slenderly extended town along the Sea of Japan It was a prosperous town since the ancient time. Running parallel from its coast, about 200 to 300 meters, there were several protruding rocks. These rocks helped diminish the strength of entering waves. Consequently, the area along the coastline has become a very good natural harbor. During the Edo Period, the town had become the landing port of gold and silver produced from Sado island. Consequently, embankment and shipbuilding technology had developed. In 1873 (Meiji 6), Japan's first oil drilling operation started in its coast. In 1888 (Meiji 21), a traditional embankment and shipbuilding technology was applied practically, making Japan's first undersea oil extraction a success. This is six years earlier than a similar operation done in USA.