Koenkai (後援会; engl. "local support groups") are an invaluable tool of Japanese Diet members, especially of the Liberal Democratic Party (LDP). These groups serve as pipelines through which funds and other support are conveyed to legislators and through which the legislators can distribute favors to constituents in return. To avoid the stringent legal restrictions on political activity outside of designated campaign times, koenkai sponsor year-round cultural, social, and "educational" activities. For example, Tanaka Kakuei used his "iron constituency", or invincible constituency, in rural Niigata Prefecture to build a formidable, nationwide political machine. But other politicians, like Ito Masayoshi, were so popular in their districts that they could refrain, to some extent, from money politics and promote a "clean" image. Koenkai remained particularly important in the over-represented rural areas, where paternalistic, old-style politics flourished and where the LDP had its strongest support.
In the classic oyabun-kobun manner, local people who were consistently loyal to a politician became favored recipients of government largess. In the 1980s, Tanaka's third electoral district in Niigata was the nation's top beneficiary in per capita public works spending. The importance of local loyalties is also reflected in the widespread practice of a second generation's "inheriting" Diet seats from fathers or fathers-in-law. This trend is found predominantly, although not exclusively, in the LDP.