The Sempill Mission was a British naval aviation technical mission led by Captain William Forbes-Sempill [1] and sent to Japan in September 1921, with the objective of helping the Imperial Japanese Navy develop its aeronaval forces. The mission consisted of a group of 30 instructors and support staff; [2] the mission was headed by Colonel Sempill and stayed in Japan for 18 months.
The Imperial Japanese Navy had closely monitored the progress of aviation of the three Allied naval powers during World War I and concluded that Britain had made the greatest advances in naval aviation, [3] they had also learned a good deal about naval aviation through their contacts within the Royal Navy. [4] In 1920, a representative had also been sent to Britain to observe air operations off the decks of Furious. In 1921, the Japanese government formally requested that the British dispatch a naval air mission, in order to develop and to provide a professional edge to Japanese naval aviation. [5] There were reservations on the part of the Admiralty about granting the Japanese unrestricted access to British technology, yet after refusing the Japanese a total of ten times, the British government relented and sent an unofficial civil aviation mission to Japan. [6] [7]
The Sempill Mission was led by Captain William Forbes-Sempill, a former officer in the Royal Air Force experienced in the design and testing of Royal Navy aircraft during World War I. [6] The mission consisted of 30 members, who were largely personnel with experience in naval aviation and included pilots and engineers from several British aircraft manufacturing firms. [6] The British technical mission left for Japan in September with the objective of helping the Imperial Japanese Navy develop and improve the proficiency of its naval air arm, [6] the British government also hoped it would lead to lucrative an arms deal. The mission arrived at Kasumigaura Naval Air Station the following month, in November 1921, and stayed in Japan for 18 months. [8] Although civilians, the Japanese granted active commissions to all members of the mission and a suitable uniform was provided. [9] Sempill was given the rank of a naval captain by the Japanese while other members of the team were given lesser ranks. [10]
The Japanese were trained on several new British aircraft such as the Gloster Sparrowhawk; as the mission also brought to Kasumigaura, well over a hundred aircraft comprising twenty different models, [Note 1] five of which were then currently in service with the Royal Air Force, including the Sparrowhawk. These planes eventually provided the inspiration for the design of a number of Japanese naval aircraft. Technicians became familiar with the newest aerial weapons and equipment-torpedoes, bombs, machine guns, cameras, and communications gear. [6] While naval aviators were trained in various techniques such as torpedo bombing, flight control and carrier landing and take-offs; skills that would later be employed in the shallow waters of Pearl Harbor in December 1941. [11] The mission also brought the plans of the most recent British aircraft carriers, such as HMS Argus and HMS Hermes, which influenced the final stages of the development of the carrier Hōshō. Although Hōshō was already launched by that time, she became the first aircraft carrier laid down as such in the world when she was commissioned in 1922, one year before Hermes. [4]
By the time the last members of the mission had returned to Britain, the Japanese had acquired a reasonable grasp of the latest aviation technology and the Sempill mission of 1921–1922, marked the true beginning of an effective Japanese naval air force. [5] Japanese naval aviation also, both in technology and in doctrine, continued to be dependent on the British model for most of the 1920s. [4] The Imperial Japanese Navy were also aided in their quest to build up their naval forces by Sempill himself, who had later become a Japanese spy. Over the next 20 years, the British Peer provided the Japanese with secret information on the latest British aviation technology. His espionage work helped Japan rapidly develop its military aircraft and its technologies before the Second World War. [12]
Kaga (加賀) was an aircraft carrier built for the Imperial Japanese Navy (IJN) and was named after the former Kaga Province in present-day Ishikawa Prefecture. Originally intended to be one of two Tosa-class battleships, Kaga was converted under the terms of the Washington Naval Treaty to an aircraft carrier as the replacement for the battlecruiser Amagi, which had been irreparably damaged during the 1923 Great Kantō earthquake. Kaga was rebuilt in 1933–1935, increasing her top speed, improving her exhaust systems, and adapting her flight decks to accommodate more modern, heavier aircraft.
Akagi was an aircraft carrier built for the Imperial Japanese Navy (IJN), named after Mount Akagi in present-day Gunma Prefecture. Though she was laid down as an Amagi-class battlecruiser, Akagi was converted to an aircraft carrier while still under construction to comply with the terms of the Washington Naval Treaty. The ship was rebuilt from 1935 to 1938 with her original three flight decks consolidated into a single enlarged flight deck and an island superstructure. The second Japanese aircraft carrier to enter service, and the first large or "fleet" carrier, Akagi and the related Kaga figured prominently in the development of the IJN's new carrier striking force doctrine that grouped carriers together, concentrating their air power. This doctrine enabled Japan to attain its strategic goals during the early stages of the Pacific War from December 1941 until mid-1942.
The Imperial Japanese Navy was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender in World War II. The Japan Maritime Self-Defense Force (JMSDF) was formed between 1952 and 1954 after the dissolution of the IJN.
Hōshō was the world's first commissioned ship that was built as an aircraft carrier, and the first aircraft carrier of the Imperial Japanese Navy (IJN). Commissioned in 1922, the ship was used for testing carrier aircraft operations equipment, techniques, such as take-offs and landings, and carrier aircraft operational methods and tactics. The ship provided valuable lessons and experience for the IJN in early carrier air operations. Hōshō's superstructure and other obstructions to the flight deck were removed in 1924 on the advice of experienced aircrews.
This is a list of aviation-related events from 1921:
Takijirō Ōnishi was an admiral in the Imperial Japanese Navy during World War II who came to be known as the father of the kamikaze.
Naval aviation is the application of military air power by navies, whether from warships that embark aircraft, or land bases.
The Imperial Japanese Navy Air Service (IJNAS) was the air arm of the Imperial Japanese Navy (IJN). The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War.
During World War II, at the beginning of the Pacific War in December 1941, the Imperial Japanese Navy (IJN) was the third most powerful navy in the world, and the naval air service was one of the most potent air forces in the world. During the first six months of the war, the IJN enjoyed spectacular success inflicting heavy defeats on Allied forces, being undefeated in every battle. The attack on Pearl Harbor crippled the battleships of the US Pacific Fleet, while Allied navies were devastated during Japan's conquest of Southeast Asia. Japanese Navy aircraft operating from land bases were also responsible for the sinkings of HMS Prince of Wales and HMS Repulse which was the first time that capital ships were sunk by aerial attack while underway. In April 1942, the Indian Ocean raid drove the Royal Navy from South East Asia. After these successes, the Japanese now concentrated on the elimination and neutralization of strategic points from where the Allies could launch counteroffensives against Japan's conquests. However, at Coral Sea the Japanese were forced to abandon their attempts to isolate Australia while the defeat at Midway saw them forced on the defensive. The campaign in the Solomon Islands, in which the Japanese lost the war of attrition, was the most decisive; they had failed to commit enough forces in sufficient time.
Ryūnosuke Kusaka, was an admiral in the Imperial Japanese Navy during World War II who served as Chief of Staff of the Combined Fleet. Fellow Admiral Jinichi Kusaka was his cousin. Kusaka was also the 4th Headmaster of Ittō Shōden Mutō-ryū Kenjutsu, a famous school of swordsmanship founded by Yamaoka Tesshū.
Zuihō was the name ship of her class of two light aircraft carriers built for the Imperial Japanese Navy. Originally laid down as the submarine tender Takasaki, she was renamed and converted while under construction into an aircraft carrier. The ship was completed during the first year of World War II and played a minor role in the Battle of Midway in mid-1942. She participated in the Guadalcanal Campaign during the rest of 1942. Significantly damaged during the Battle of the Santa Cruz Islands in that campaign, after repairs Zuihō covered the evacuation of Japanese forces from Guadalcanal in early 1943.
The Decisive Battle Doctrine was a naval strategy adopted by the Imperial Japanese Navy prior to the Second World War. The theory was derived from the writings of American naval historian Alfred Thayer Mahan. In the Decisive Battle Doctrine the Japanese navy would win a war by fighting and winning a single, decisive naval action. The idea gained broad acceptance following the Russo-Japanese War, where a well-trained, smaller Japanese naval force gained a decisive victory in the Sea of Japan at the Battle of Tsushima, defeating the Imperial Russian Navy of their rival the Russian Empire, a western naval power. Operational plans thereafter were influenced by the effective naval gunnery Japan demonstrated at Tsushima.
The Mitsubishi 1MF was a Japanese carrier fighter aircraft of the 1920s. Designed for the Mitsubishi Aircraft Company by the British aircraft designer Herbert Smith, the 1MF, also known as the Navy Type 10 Carrier Fighter was operated by the Imperial Japanese Navy from 1923 to 1930.
The Gloster Sparrowhawk was a single-seat fighter aircraft designed and produced during the early 1920s by the British aircraft manufacturer Gloster.
William Francis Forbes-Sempill, 19th Lord Sempill,, was a Scottish peer and record-breaking air pioneer, who was later shown to have passed secret information to the Imperial Japanese military before the Second World War. Educated at Eton, he began his career as a pilot in the Royal Flying Corps, and then served in the Royal Naval Air Service and Royal Air Force during the First World War. In 1921, Sempill led an official military mission to Japan that showcased the latest British aircraft. In subsequent years, he continued to aid the Imperial Japanese Navy in developing its Navy Air Service.
The Zuihō class (瑞鳳型), also known as the Shōhō class (祥鳳型), consisted of two aircraft carriers built for the Imperial Japanese Navy (IJN) before World War II, the Zuihō and Shōhō. Both ships were originally built as submarine tenders, but were subsequently converted into carriers. Completed in early 1942, Shōhō supported the invasion forces in Operation MO, the invasion of Port Moresby, New Guinea, and was sunk by American carrier aircraft on her first combat operation during the Battle of the Coral Sea on 7 May. Shōhō was the first Japanese aircraft carrier to be sunk during World War II. Zuihō played a secondary role in the Battle of Midway in mid-1942 and did not engage any American aircraft or ships during the battle. The ship participated in the Guadalcanal campaign during the rest of 1942. She was lightly damaged during the Battle of the Santa Cruz Islands during this campaign and covered the evacuation of Japanese forces from the island in early 1943 after repairs.
The First Carrier Division was an aircraft carrier unit of the Imperial Japanese Navy's First Air Fleet. At the beginning of the Pacific Campaign of World War II, the First Carrier Division consisted of the fleet carriers Akagi and Kaga. The division participated in the Attack on Pearl Harbor and Indian Ocean Raid. After Akagi and Kaga were sunk at the Battle of Midway in June 1942, carriers Shōkaku, Zuikaku, and Zuihō were redesignated as the First Carrier Division.
A kōkūtai (航空隊) was a military aviation unit in the Imperial Japanese Navy Air Service (IJNAS), similar to the air groups in other air arms and services of the time. Some comparable units included wing in the British Royal Air Force, gruppe in the German Luftwaffe, and groupe in the French Armée de l'Air.
The Imperial Japanese Navy Air Service was under the control of the Navy Aviation Bureau.
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