A huge cave on the Japanese mainland located across the sea from Ama Island in You Only Live Twice. When two islanders are found dead in their boat, James Bond (Sean Connery) and his “wife,” Kissy (Mie Hama), investigate and discover deadly phosgene gas in the cave. Diving into the water, they eventually find their way to an extinct volcano, which is the site of the secret rocket base of Blofeld (Donald Pleasence).