in 1938–39 with the ferocious bombardment of cities deep in the Chinese interior by land-based medium bombers and concluded during 1941 with an attempt by tactical aircraft, both carrier and land-based, to cut communication and transportation routes in southern China. Although, the 1937–41 air offensives failed in its political and psychological aims, it did reduce the flow of strategic materiel to China and for a time, improved the Japanese military situation in the central and southern parts of the country. The China War was of great importance and value to the Japanese naval aviation in demonstrating how aircraft could contribute to the projection of naval power ashore. Despite the fierce rivalry between the military branches, in the fall of 1937 General Matsui Iwane, the Army general in command of the theater, admitted the superiority of the Naval Air Services. His combat troops relied on the Navy for air support. Naval bombers such as the Mitsubishi G3M and Mitsubishi G4M were used to bomb Chinese cities. Japanese fighter planes, notably the Mitsubishi Zero, gained tactical air superiority; control of the skies over China belonged to the Japanese. Unlike other naval airforces, the IJNAS was responsible for strategic bombing and operated long ranged bombers. The Japanese strategic bombing was mostly done against Chinese big cities, such as Shanghai, Wuhan and Chonging, with around 5,000 raids from February 1938 to August 1943. The bombing of Nanjing and Guangzhou, which began on 22 and 23 September 1937, called forth widespread protests culminating in a resolution by the Far Eastern Advisory Committee of the League of Nations. Lord Cranborne, the British Under-Secretary of State For Foreign Affairs, expressed his indignation in his own declaration. Pacific war At the beginning of the Pacific war the Imperial Japanese Navy possessed the most powerful carrier force in the world, through combination of excellent ships, well-designed aircraft, and unsurpassed aviators. The Navy Air Service consisted of five naval air fleets. The Japanese had a total of ten aircraft carriers: six fleet carriers, three smaller carriers, and one training carrier. The 11th Air Fleet: contained most of the Navy's land based strike aircraft. One important advantage exercised by the Japanese at the start of the war was their ability to mass carrier air power. In April 1941 the First Air Fleet was created, concentrating the Navy's carriers into a single powerful striking unit. The Kido Butai (Mobile Unit/Force) was the