Kushima Masashige was master of Takatenjin Castle in Tootoumi and father of Houjou Tsunashige and Houjou Tsunafusa. His family served the Imagawa Clan for generations, and it is likely that he served Imagawa Ujichika. There are theories that he died in battle with Takeda Nobutora in the service of the Imagawa Clan or at the Battle of Iidagawara serving the Houjou Clan, among others.