Leading up to World War II, Japan and Germany were well aware that their ships, tanks and planes were completely dependent on oil. The Fischer- Tropsch process—invented in Germany some years earlier—allowed the Germans to produce 72,000 barrels a day of synthetic fuel from coal by 1940. However, the synthetic fuels were not enough and the principal goal of the march into the Soviet Union was the rich oilfields of Baku on the Caspian Sea.