As an important document Sejong Sillok Jiriji the records of Dokdo in the latter two documents, Dongguk Munheon Bigo and MangiYoram , present a particularly clear description stating: ¡°Ulleungdo and Usando are lands of Usanguk [or the State of Usan], and Usando is the island that Japanese call Songdo [i.e. Matsushima].¡± No other record of this period contains a clearer statement which shows that Usando is an old name of Dokdo.
Initially, the US recognized Dokdo as Korea¡¯s territory, and the temporary change in US's position was only due to strategic lobbying by Japan. In October 1951, the Japanese government submitted to the House of Representatives, the Map of Japanese Territory, drawn according to the San Francisco Peace Treaty. In this map, Dokdo lies outside the line marking the boundary of Japanese territory, showing that the island is not Japanese territory.
Also we both should follow the international norms about the name of sea between our 2 countries, so you should use "East sea" also not only use "Sea of Japan". It should be better to change the name from Takeshima to "Dokdo".