Ships
- IJN Hosho Captain from 27 December 1922 · Relieved on 1 April 1923
Jiro Toshima was a captain in the Imperial Japanese Navy and the first commanding officer of the aircraft carrier Hosho. He took command on 27 December 1922, the day the ship was commissioned at the Yokosuka Navy Yard, and he had already seen her through the last of her completion. She had been launched at the Asano yard in Tsurumi on 13 November 1921 and towed to Yokosuka to be finished. Hosho was the first carrier the Japanese Navy built as a carrier from the start of construction, and the first ship of that kind to enter service in any navy.
She was a small ship for so new a job. On a standard displacement of about 7,470 tons she measured roughly 168 meters, with a flight deck running the length of the hull over two hangars and a pair of elevators. Two turbine shafts were intended to give her about 25 knots. As completed she was arranged for a small air group, four 14-centimeter guns, and two 8-centimeter anti-aircraft guns, and a compact island stood on the starboard side. The design had changed more than once while she was on the ways, and much of the gear for flying from a ship was still unproven.
Those proofs began while Toshima was in command. In February 1923, off Yokosuka, a British pilot named Jordan made the first landing on her deck. In March a Japanese naval aviator, Lieutenant Shunichi Kira, followed with the first landing by one of the Navy’s own pilots. The approaches were short, the deck was still obstructed by the island, and the crew was learning how to move aircraft between hangar and flight deck. The landings of that late winter were the practical start of Japanese carrier flying.
Toshima was relieved on 1 April 1923 by Heizaburo Fukuyo. His own time in the ship had lasted a little over three months and covered commissioning and those first deck landings. The officers who held Hosho after him, among them Ryutaro Kaizu and Seizaburo Kobayashi, kept her at the work of trials and training through the middle of the 1920s, while she was still the fleet’s only aircraft carrier. The ship he handed over in the spring of 1923 remained in service through the Pacific War, brought servicemen home afterward, and went to the breakers in 1947. His captaincy was the opening of that long life.