Learn about the Japanese suicide submarines. The Japanese naval engineers developed this revolutionary suicide weapon, known as the Kaiten, from an existing torpedo known as the type 93. It had over one and half tonnes of explosives in its war head. Historian Tosh Minohara explores the island of Ozushima where the Japanese developed this revolutionary weapon and trained the pilots to drive them. The first ever Kaiten attack sinks the fuel supply ship USS Mississinewa.