Analysis of satellite charts of the East Sea gathered between 1993 and 2008 supports the claim that the Dokdo Islets have been Korean territory since ancient times, the National Oceanographic Research Institute claimed Sunday.

The institute observed the East Korean Warm Current, which advances northward along the southeastern coast of the Korean Peninsula. While passing the north of Ulleung Island, the current either turns east or flows south toward Dokdo and on to the Oki islands in Japan, where it moves northeastward. It also causes frequent swirls 100 km in radius turning clockwise near Ulleung and Dokdo.

NORI concluded that it would have been possible to travel on the current between Gyeongju or Pohang and Ulleung Island and between Ulleung and Dokdo and Oki islands using primitive craft such as rafts and canoes.  

But the journey from the Japanese direction would have been very difficult because it would go against the flow of the current, NORI said. This strongly supports claims that Korea had access to Dokdo from before the Christian era and suggests it would have been under Korean territorial influence.