on board a Japanese carrier or a seaplane tender were made an integral part of a ships complement, when land-based or shore based (seaplane) air units were formed, the bases at which they were stationed were seen as equivalent to the ship of assignment for the carrier-based hikōtai. There were over 90 naval air groups at the start of the Pacific War. History The land-based kōkūtai system was set up in 1916, determined that naval air stations and air groups would be organized as needed, at either naval ports (gunkō) or strategic ports (yōkō). Their designations were taken from the names of those places and functioning under the authority of those stations. In 1919, the IJN set out new regulations that in a time of war, emergency or maneuvers provided for the organization of "special air groups" (tōkusetsu kōkūtai), which could be designated either by a place or by a numerical designation. They could be either land- or carrier-based, but in general they were largely land-based and would be given numerical designations. In most cases the basis of these formations were created from elements drawn from existing air groups. The first such unit was the 11th Air Group, established briefly in 1936. While regulations establishing land-based air groups were set forth in 1916 and 1919, it was not until the early 1930s that a series of regulations and instructions, set forth the specific internal organizations of air groups, their locations, functions, and their training, though these changed from time to time right up to the end of the Pacific War. In November 1936, the IJN arranged for the organization of special combined air groups (tōkusetsu rengō kōkūtai), which were composed of two or more air groups. They were created in order to provide greater air strength under a single command. The 1st and 2nd combined air groups were formed in July 1937, at the beginning of the China War, and were the backbone of the navy's air operations in the first several years of that conflict. Standing combined air groups (jōsetsu rengō kōkutai) intended to be more permanent, were established in December 1938. Two of these were established before the Pacific War: the 11th was organized in December 1938, and the 12th which was formed in 1939. Until the very end of the 1930s most kōkutai were composed of a mix of aircraft types, with seaplanes predominating initially, but with