I-30 carried strategic raw materials and Type 91 aerial-torpedo plans from Japan to Europe, then returned with German designs, radar-related equipment, 20 mm guns, and other valuable cargo. National technology comparisons are rarely simple because governments distribute limited researchers and money across different priorities. One ally may therefore be strong precisely where another has accepted a weakness. The exchange allowed the Axis partners to hedge those different bets.
Notable Point · 53:55-55:24
I-30 and complementary Axis technology bets
The submarine exchanged Japanese raw materials and torpedo plans for German radar, weapons, and other designs, allowing the allies to offset different research priorities.