quest to build up their naval forces by Sempill himself, who had 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. Carrier aviation Japanese interest in the potential of carrier operations demonstrated by the observations on board led to the inclusion of an aircraft carrier in the eight-eight fleet program of 1918. The 7,470-ton was laid down in December 1919 at Yokohama. Hōshō was the second warship after the British to be designed from the keel up as an aircraft carrier and the first one to be completed as from the keel up. In the 1920s, the larger percentage of aircraft that were initially acquired and inducted into service were land based seaplanes whose main tasks were reconnaissance and anti-submarine patrols. The Japanese had drawn up plans for the formation of 17 squadrons of these aircraft, but budgetary constraints limited the units to eleven until 1931. Under the terms of the Washington Naval Treaty two incomplete capital ships were allowed to be rebuilt as carriers, for the Japanese; and . However, Amagi was damaged during the Great Kanto earthquake in 1923 and became a replacement. Akagi was completed in 1927 while Kaga completed a year later. With these two carriers much of Imperial Japanese Navy's doctrines and operating procedures were established. When Hōshō was completed, little thought was given to naval aircraft in an offensive role and moreover with only one carrier there was insufficient consideration given to carrier doctrine within the Japanese naval establishment. However, in 1928 the First Carrier Division was formed with three carriers and the study of the role of aircraft carriers in a naval engagement was initiated. Because of the short range of carrier aircraft at the time, many in the naval hierarchy were still very much surface oriented. They viewed carrier aircraft to be employed as support for the main battle fleet and not as offensive weapons. Aircraft were to act as scouts and spotters, layers of smoke screens for naval gunfire, fleet air defense, and later (with the increase in aircraft performance) as a means to attack battleships and other surface targets. Naval aviators however, had a different perspective. Believing that a major aerial engagement to clear the space over