was a steel-hulled, steam gunboat, serving in the early Imperial Japanese Navy. She was the fourth and final vessel to be completed in the four-vessel and was named after Mount Akagi in Gunma Prefecture.
Background
Akagi was the last in a series of 600-ton gunboats, which included the , , and , built from 1885–1886 under the supervisor of the French naval architect, Bellard. She was the only vessel in the class to be equipped with a steel-hull instead of an iron or composite hull.
Construction
Akagi was designed with a horizontal double expansion reciprocating steam engine with two cylindrical boilers driving two screws. She also had two masts for a schooner sail rig. Initially, she was armed with one Krupp L/22 breech-loading gun, one Krupp L/22 breech-loading gun and two quadruple 1-inch Nordenfelt guns, and was intended primarily for port defense.
However, by early 1894, she had been rebuilt with a high short forecastle and four 120-millimeter guns arranged on her centerline, six 47-mm rapid-fire guns (two by the bridge, facing forward, and two mounted in small sponsons on either side of the hull). All guns were protected by gun shields. Well-armed for her size, she was soon rendered obsolete with the introduction of larger protected cruisers into the Imperial Japanese Navy inventory.
Service record
upright=1.5|thumb|[[Ukiyo-e depicting Akagi in the Battle of the Yalu River in the First Sino-Japanese War, titled "Lieutenant-Commander Sakamoto of the Imperial Warship Akagi, Fights Bravely"]]
upright=1.5|thumb|IJN Gunboat Ōshima
Akagi was laid down at the Onohama Shipyards on 20 July 1886 and launched on 7 August 1888. She was completed on 20 August 1890.
Akagi saw combat service in the First Sino-Japanese War, initially patrolling between Korea, Dairen and Weihaiwei. She was included in the Japanese squadron at the Battle of the Yalu River by Japanese Admiral Itō Sukeyuki, as he needed a ship with shallow draft to explore the shallows of Korea Bay. When the Japanese fleet closed with the Chinese Beiyang Fleet on 17 September 1894,