From the seventeenth century to the mid-nineteenth century Dokdo and Ulleung were called Matsushima and Takeshima, respectively, in Japan. The oldest Japanese source that mentions Dokdo is “Records on Observations on Oki” (“Onshū shichō gōki,” 1667). This text was written by Saitō Hōsen, who was a government official of Matsue domain (in present-day Shimane Prefecture) and who visited the Oki Islands on behalf of the daimyo of Matsue domain. In this text Saitō wrote, “Murakawa (a merchant who traded at Ulleungdo) received approval from the government and sent a large ship to Iso Takeshima (Takeshima, Ulleungdo).” This statement shows that Saitō recognized Ulleungdo as a foreign land to which trade ships sailed.
In “Records on Observations on Oki” is written, “Northwest of Japan, we make this land to be the boundary,” meaning that the Oki Islands were the northwestern territorial limit of Japan. In addition, the Edo shogunate published Japanese maps in five editions. Of these, the first four maps were based on regional maps and the fifth one was compiled from surveys conducted by Inō Tadataka under the order of the shogunate. These five government-commissioned maps compiled by the Edo shogunate excluded Dokdo from the territory of Japan.