There are records about Ulrundo and Dokdo on Korean documents such as 『Koryosa geography』․『Sejong record geography』. From those records we can say, people knew about two islanda in those days. But Japanese claim, Korean did not know about the existense of Dokdo until 1904, because there are different views about Ulrundo and Dokdo on Korean documents. However We can declare that their opinions is not true through the discovery of Japanese ancient document『The report on Takesima』. On this record, Korean knew about the exsistense of two islands Mugurusemu(Ulrundo) and Burunsemi(Dokdo) in The East Sea. These contents correspond with Korean records.