Submarines of the Imperial Japanese Navy
The submarines that Electric Boat sold to Japan were based on the Holland designs, known as Holland Type VIIs similar to the American s. The five imported Hollands were originally built at Fore River Ship and Engine Company in Quincy, Massachusetts under Busch's direction for the Electric Boat Company back in August–October 1904. They were shipped by freighter from Seattle, Washington in Knock-down kit form to Japan, and then reassembled by Arthur Leopold Busch at the Yokosuka Naval Arsenal, which was then Japan's largest naval shipyard, to become Hulls No. 1 through 5 and were designated Type 1 submarines by the Japanese Navy.
Monsun Gruppe
The German invasion of the Soviet Union in 1941 had ended the use of overland routes which were for the delivery of strategic materials from southeast Asia, and few Axis ships were able to avoid Allied patrols of the North Atlantic. Japan was interested in exchanging military technology with Germany, the Japanese submarine "I-30" initiated the submerged transport of strategic materials in mid-1942 by delivering 1500 kg of mica and 660 kg of shellac. Japanese submarines designed for the vast distances of the Pacific were more capable transports than the compact German U-boats which were designed for operations around coastal Europe; but large Italian submarines had proved ineffective for convoy attacks. The Italian Royal Navy ("Regia Marina") converted seven Italian submarines operating from BETASOM into "transport submarines" in order to exchange rare or irreplaceable trade goods with Japan. They were: The "Bagnolin", the "Barbarigo", the "Cappellini" (renamed "Aquilla III" in May 1943), the "Finzi", the "Giuliani", the "Tazzoli" and the "Torelli".