Kotaka was a torpedo boat of the Imperial Japanese Navy. She was ordered in 1885 from the shipbuilder Yarrows in London, Great Britain, where she was built in parts along Japanese specifications, and then assembled in Yokosuka Naval Arsenal, Japan.
She participated in the First Sino-Japanese War (1894–1895) and the Russo-Japanese War (1904–1905). She was decommissioned on 1 April 1908, to become a training ship. She was retired on 1 March 1916, but again reactivated in 1917, ending her career in January 1927.
When launched in 1888, the Kotaka, at 203 tons, was the largest torpedo boat in the world, and "was the forerunner of torpedo-boat destroyers that appeared a decade later" (Kaigun, David C. Evans). She was armed with four 1-pounder (37 mm) quick-firing guns and six torpedo tubes. In the following years, the Imperial Japanese Navy equipped herself with much smaller torpedo boats of French design, but in her trials in 1899, the Kotaka demonstrated that she could go beyond a role of coastal defense, and was capable of following larger ships on the high seas. The British shipbuilder Yarrow "considered Japan to have effectively invented the destroyer" (Howe).
In 1904, Kotaka was experimentally refitted with a mixed oil and coal engine, instead of her original coal-only propulsion.
The Hayabusa-class torpedo boats were constructed for the Imperial Japanese Navy as part of the ten-year naval expansion program. They were completed between 1900 and 1904.
All of the vessels served in the Russo-Japanese war, the Kiji being mined off Port Arthur, though a new Kiji was built as a replacement. They were notable for their attacks on the Russian fleet on the night of 27/28 May 1905 during the Battle of Tsushima, expending a large number of torpedoes. They were able to inflict significant damage on a number of Russian ships that were scuttled or sunk the next day.
After serving in World War I, all remaining fifteen vessels were decommissioned between 1919 and 1923, some were scrapped, others turned into auxiliaries.