Tsushima Subprefecture (対馬æ¯åºÂ, Tsushima-shichà Â, ) was an administrative subdivision of Nagasaki Prefecture, Japan. The subprefecture was the administrative body for Tsushima Island which lies between Kyà «shà « and the Korean Peninsula. The only municipality in Tsushima Subprefecture is Tsushima City, which itself is the composite of the merger of six smaller towns (Kamiagata: Kami-agata, Kami-tsushima, Mine and Shimoagata: Izuhara, Mitsushima, Toyotama) on the island.