Baron was a general in the Imperial Japanese Army , Japanese ambassador to Germany before and during World War II — and unwittingly a major source of communications intelligence for the Allies . His role was perhaps best summed up by General George C. Marshall , who identified Ōshima as " our main basis of information regarding Hitler 's intentions in Europe " . After World War II , he was convicted of war crimes and sentenced to life imprisonment , but was paroled in 1955
war crimes
Japanese war crimes
Hiroshi Ōshima