GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
While Japan had domestic oil fields in Akita, Niigata and Nutsu, their production was minimal compared to American output. They looked to the oil fields in Korea, Manchuria, China, Burma and Formosa, then ultimately the Dutch East Indies, Sumatra, Borneo and Malayasia. They even purchased oil from neutral Sakhalin and Siberian sources.
They had sufficient refineries on the home islands to refine the inbound oil, they simply did not have the ability to properly protect the tankers that were vital to the process.
They had sufficient refineries on the home islands to refine the inbound oil, they simply did not have the ability to properly protect the tankers that were vital to the process.