Since the stock of such as old rice harvested one or two years before had continuously increased, the government introduced adjustment of production of rice in 1970 which mainly included a ban for developing new rice fields, setting up a limitation of purchase by the government, introduction of the voluntary marketed rice system and allocation of a certain area of crop diversification.
昭和45年（1970年）、古米や古々米などの在庫が増加の一途をたどったため、政府は、新規の開田禁止、政府米買入限度の設定と自主流通米制度の導入、一定の転作面積の配分を柱とした米の生産調整を開始した。