16. The Shift to Underwater Trade
The sea route between Germany and Japan was long and hazardous. It stretched from Europe via the Atlantic, around Africa and thence into and across the Indian Ocean, and finally to the Pacific. Despite that, in a twelve-month period from late 1941 to late 1942, twelve surface blockade runners managed to complete the journey from the Far East and deliver more than 60,000 tons of supplies to German-occupied France. By late 1942, however, a combination of British intercepts of Japanese communications that led to increased interception of blockade runners, coupled with mining the Bay of Biscay, cut deeply into the trade between the Axis partners. In 1943, the Germans received only a third of the supplies that had reached them from the Far East the previous year. So a decision was made to shift the trade from surface blockade running ships, to underwater submarines.
