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.
Attack on Sydney Harbour
The Imperial Japanese Navy originally intended to use six submarines in the attack on Sydney Harbour: B1-type submarines , , , and , and C1-type submarines and . The six submarines made up the Eastern Attack Group of the 8th Submarine Squadron, under the command of Captain Hankyu Sasaki.