HIJMS Ryūjō (龍驤,lit. Dragon Horse)was a Japanese light aircraft carrier used during World War II. It was completed in 1931 and entered service with the Imperial Japanese Navy in 1933. She was sunk by American dive bombers and torpedo bombers during the Battle of the Eastern Solomons on August 24th, 1942.
Ryūjō was originally planned as a seaplane tender to replace the aging Wakamiya, but this was later changed to a conventional aircraft carrier of around 9,800-ton standard displacement. Her light displacement was intended to exploit a loophole in the Washington Naval Treaty of 1922. Under the Treaty, Japan's total tonnage of aircraft carriers was limited to 81,000-tons, but aircraft carriers under 10,000-ton standard displacement were not regarded as "aircraft carriers". While Ryūjō was under construction in 1930, the London Naval Treaty finally closed the above mentioned loophole in the Washington Naval Treaty; consequently, Ryūjō was the only light aircraft carrier of her type to be completed by Japan.
In August to December 1937, Ryūjō supported land operations of the Imperial Japanese Army in China as flagship of Carrier Division 1. After her less than satisfactory performance there, Ryūjō received extensive reconstruction at Yokosuka.In World War II, Ryūjō was the flagship of the Fourth Carrier Division . The presence of large fleet carriers meant that she was initially assigned to secondary tasks. Her reconstruction proved successful and the performance of her air group, as well as the ship herself in high seas, was satisfactory. In December 1941, Ryūjō supported the invasion of the Philippines, providing air cover for the landings at Davao on 20 December at Jolo on 25 December. In January 1942 she supported the conquest of Malaya and in February 1942 she attacked American-British-Dutch-Australian forces around Java. On 1 March 1942 she took part in the Battle of the Java Sea, assisting in the sinking of USS Pope. In the same month, she operated against the Andaman Islands and along the coast of Burma. In early April, as part of the Indian Ocean raid, Ryūjō attacked shipping in the Bay of Bengal. Together with the cruisers Chōkai , Kumano, Suzuya, Mogami, Mikuma, Yura, and four destroyers, she sank 23 merchant ships. On 6 April she launched air strikes against Cocanada and Vizagapatam in India. In June 1942 Ryūjō was part of the Northern Force that attacked the Aleutian Islands. Ryūjō's planes struck Dutch Harbor on Unalaska Island on 3 June and 4 June 1942. During this operation, one of the Zero fighters from the Ryūjō, flown by Petty Officer Tadahito Koga, crash landed on the island of Akutan. Koga was killed in the crash due to a broken neck, but the aircraft remained largely intact. The aircraft, later dubbed the Akutan Zero, was the first intact Zero fighter to fall into the hands of U.S. military intelligence. In August 1942 she was reassigned to Carrier Division 2, and with Shōkaku and Zuikaku she was dispatched to the Solomon Islands. Ryūjō's role in the operation was to support a convoy of transports that were to reinforce and resupply Japanese troops on Guadalcanal, and to attack the Allied air base at Henderson Field. This force was commanded by Rear Admiral Chuichi Hara in the cruiser Tone. Meanwhile, the fleet carriers operated against the U.S. Navy's aircraft carriers. This operation resulted in the Battle of the Eastern Solomons.On 24 August 1942, Ryūjō, escorted by the cruiser Tone and the destroyers Amatsukaze and Tokitsukaze, launched a strike against Henderson Field on Guadalcanal from a position 161 km (100.0 mi) north of Tulagi. The first wave, launched at 12:20, consisted of six Nakajima B5Ns armed with general-purpose bombs and an escort of six Zero fighters. A second wave of nine Zero was launched at 1248. By 14:00, Rear Admiral Hara's airmen radioed they had successfully bombed the airfield, losing two fighters and three bombers to enemy fire (one other bomber crash-landed on Ndai Island). Early in the afternoon, the task force was approached by two B-17 bombers, although these aircraft were chased off by anti-aircraft fire and the launch of six Zero fighters. At approximately 15:50, while beginning launching operations, she was attacked by twenty-nine dive bombers and five torpedo bombers from the USS Saratoga, and was hit by four bombs (sources differ as to how many) and one torpedo. The torpedo hit flooded the starboard engine room and jammed the ship's rudder, causing Ryūjō to turn in circles and begin listing to starboard. She was soon on fire along her entire length and her engines eventually stopped. As Amatsukaze went alongside to assist in damage control, two B-17 bombers emerged from the clouds and made an unsuccessful attack against Ryūjō. Though her fires had been brought under control, efforts to contain flooding caused by the torpedo hit proved fruitless and the order to abandon ship was given. By 20:00 the carrier capsized and sank along with approximately 120 of her crew and four aircraft still on board in the hangars. Her remaining survivors, including Captain Kato, had been taken off by her escorts. Ryūjō was struck from the Navy List in 10 November 1942.