Submarines of the Imperial Japanese Navy
Imperial Japanese Navy submarines originated with the purchase of five Holland type submarines from the United States in 1904. Japanese submarine forces progressively built up strength and expertise, becoming by the beginning of World War II one of the world's most varied and powerful submarine fleets.
Imperial Russian Navy
Due to the ongoing blockade of Port Arthur in 1904, the Imperial Russian Navy dispatched their remaining submarines to Vladivostok, and by the end of 1904 the last of seven subs had reached their new base there. Using the seven boats as a foundation, the Imperial Russian Navy created the world's first operational submarine fleet at Vladivostok on 1 January 1905. On 14 February 1905 the new "submarine fleet" sent out its first combat patrol consisting of the vessels "Som" and "Delfin". With patrols varying from 24 hours to a few days, the sub fleets first enemy contact occurred on 29 April 1905 when Imperial Japanese Navy torpedo boats fired upon "Som", withdrawing after failing to score a hit. On 1 July the Russian submarine "Keta" made contact with two Japanese torpedo boats in the Tartar Strait. "Keta" could not submerge quick enough to obtain a firing position and both adversaries broke contact.