The Oshima Maru was the fishing sampan owned by Jiro Takahashi. When the Japanese occupation of Hawaii made gasoline hard to come by, Takahashi employed a handyman named Eizo Doi to convert it into a sailing vessel. Takahashi and his sons Hiroshi and Kenzo were able to feed themselves throughout the occupation. When Takahashi was hired into working for the occupiers as a radio spokesperson for Japanese propaganda, his sons were taught by Takahashi to sail the Oshima Maru on their own to support themselves.