IJN Hiryu History

The aircraft carrier made its debut in the fighting of World War 1 (1914-1918) but its true impact was not felt until World War 2 (1939-1945). In the lead-up to the second grand conflict, various carrier designs were enacted, sometimes limited by the various naval treaties established after World War 1 while, other times, designs were of an all-new approach showcasing greater displacements and aircratf-carrying capabilities. At any rate, it was certain that the aircraft carrier was quickly becoming a mainstay of naval firepower, particularly as naval aircraft designs were beginning to match, or outpace, their land-based counterparts. Before the end of World War 2, the aircraft carrier would supplant the mighty battleship as the King of the Seas - its lethality and tactical value only matched by the nuclear-powered ballistic missile submarines appearing in the post-war years.

IJN Hiryu was originally built to the same design as what would have been her sister, IJN Soryu (detailed elsewhere on this site), but was so heavily modified through a longer hull, wider beam, greater displacement and elevated forecastle section that she became her own "one-off" class. Construction began on July 8th, 1936 by the Yokosuka Naval Arsenal and this led to her launching on November 16th, 1937. She was formally commissioned for IJN service on July 5th, 1939. Her name translated was "Flying Dragon".

As built Hiryu displaced 17,300 tons (long) under standard load and featured an overall length of 746 feet with a beam of 73.1 feet and a draught down to 25.6 feet. Power was from 8 x Kampon water-tube boiler units with 4 x geared steam turbines developing 153,000 shaft horsepower to 4 x shafts. Maximum speed (in ideal conditions) was 34 knots with a range out to 10,330 miles when steaming at 18 knots. Her crew complement totaled 1,100 men and armor protection reached six inches at the waterline belt and over two inches along the deck. Her onboard stowage and supply space allowed for up to sixty-four total combat aircraft to be hauled and up to nine or ten spare airframes could be held in reserve. Aircraft types supported included the Mitsubishi A6M fighter, Aichi D3A dive bomber and the Nakajima B5N torpedo bomber - this gave the warship a broad tactical reach against many target types including land-based ones, inbound aerial threats and enemy warships.

On the whole, her profile was consistent with the designs of the period - save perhaps her exposed and elevated island superstructure off to portside - pre-war designs typically had flushed top decks so as to provide a complete unobstructed landing/take-off surface for warplanes. Her hull looked very much the part of a traditional cruiser but with a flight deck eliminating an irregular profile silhouette. Three hangar elevators were in play when moving aircraft about and nine arrestor wires were stretched about the flight deck for aircraft recovery.

Armament, while largely defensive in nature, was led by 6 x twin-gunned 127mm Type 89 Dual-Purpose (DP) guns. She also carried 7 x triple-gunned 25mm Type 96 Anti-Aircraft (AA) guns and 5 x twin-gunned 25mm gun emplacements for closer-ranged defense. This gun arrangement left Hiryu lightly defended as warships of World War 2 went - particularly the ultra-important aircraft carrier.

For her career, Hiryu participated in the Japanese surprise attack on Pearl Harbor, Hawaii (1941) which marked the American entry into the war, the Battle of Wake Island (December 1941), several operations encompassing the Dutch Indies campaign of 1942, the assault on Darwin, Australia, and Indian Ocean raiding operations. Her most notable action after Pearl was the Battle of Midway (June 1942) which saw her ultimate end - she was scuttled on June 5th after having taken bombs from aircraft launched by USS Enterprise, USS Hornet, and USS Yorktown. The American victory at Midway marked the first turning point against the Japanese Empire in the Pacific War, the battle marking the loss of four major IJN aircraft carriers.

With these losses, a sixteen-strong aircraft carrier program was enacted by the Japanese Navy to shore up losses. These were based on a further modified version of Hiryu. However, only three were commissioned in time to serve in the war - which ended with the Japanese surrender in August of 1945.

IJN Hiryu Specification




- Aircraft / Offshore Support

- Blue Water Operations

- Fleet Support

- Hunter

- Direct-Attack



728.4 ft (222.02 m)

Width / Beam:

73.1 ft (22.28 m)

Height / Draught:

25.4 ft (7.74 m)


Displacement (Surface):

17,300 tons


8 x Kampon water-tube boilers with 4 x Geared steam turbines developing 153,000 horsepower and driving 4 x shafts.


Speed (Surface):

35 kts (40 mph)


7,670 nm (8,826 miles; 14,204 km)


12 x 5" (127mm) Type 89 Dual-Purpose (DP) guns in twin-gunned turrets.

31 x 25mm Anti-Aircraft (AA) guns in seven triple-gunned turrets and five twin-gunned turrets.


64 combat aircraft of various types including fighters, torpedo bombers and dive bombers. Typical loadout was Mitsubishi A6M, Nakajima B5N, and Aichi D3A aircraft respectively. An additional nine or so airframes carried for spare parts.

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