First, let me explain the locational basis. Dokdo, a Korean land belonging to Ulleung-gun, has a clear ground for being our land. The distance between Dokdo and the nearest Japanese territory (Oki Island) is 157.5km, so you cannot see Dokdo in Japan, but the distance between Ulleungdo and Dokdo is 87.4km, so you can see Dokdo with the naked eye on a clear day.
In the early Joseon dynasty's observation book, Sejong Silokjiriji (1454), there is a record saying that the two islands of Ulleungdo and Dokdo are not far from each other, so you can see them if the weather is clear. In fact, but there were no actual records, so Korea constantly observed Dokdo with the Ulleungdo residents for about a year and a half from July 2008 to December 2009. As a result, I was able to see Dokdo 3~4 times a month on average.
Next I will explain the historica basis. From the end of the 7th century, Japan faced Ulleungdo, including Dokdo, and began to cause conflict. Joseon had a fierce debate with Japan for three years, and eventually Japan recognized Dokdo as the land of Joseon in 1696. There is a famous anecdote here. In 1693, Ahn Yong-bok, a fisherman, was fishing on Ulleungdo. However, he strongly insisted that the Koreans went to Joseon territory under the commander of Hoki. Because of this, the Edo shogunate returned him to Chosun, and on December 25, 1695 inquiries about the Tottori Domain (response to the Tottori Domain), and on January 28, 1696, the Japanese were instructed to ban travel to Ulleungdo.
Also, there are many records that Dokdo is our land. ¡ºSejong Siloji Ridge¡»(1454) records that Ulleungdo (Mureung) and Dokdo (Usan) are two islands belonging to Uljin County, Gangwon-do. Also, the records on Dokdo are other publicly recognized documents such as ¡ºShinjeung Dongguk Yeoji Sungram¡»(1531), ¡ºDongguk Literature Notes¡»(1770), ¡ºManggi Cradle¡»(1808), ¡ºExtended Literature Notes¡»(1908). In addition, Dokdo and Ulleungdo are painted in yellow, the same color as the Korean Peninsula, in the ¡ºShinchan Joseon Gukjeon(1894)¡». In other words, it can be said that it is a map that Japan recognizes as ¡°Dokdo is the land of Joseon¡±. In addition, there are many old maps and data indicating that Dokdo is not Japanese, but is ours, such as ¡ºChosun Kingdom Evangelism¡» made in France and ¡ºThree Kingdoms Map¡» made in Japan.