Gosamaru (護佐丸, d. 1458) was a Ryukyuan Lord (Aji)[1] of Yomitanzan and, later, Nakagusuku. He was also known as Seishun (盛春), and by the Chinese name Mao Guoding (毛國鼎, J: Mō Kokutei).[1] He supported Shō Hashi, first king of the Ryukyu Kingdom, in his conquest of Hokuzan and unification of Okinawa Island. He committed suicide in 1458 during a battle with the Katsuren Aji, Amawari.