Thus, in Heian period, Imperial Court began to launch political measures to recover the shozei for the purpose of maintaining the tribute-to-central system, such as introduction of 'shozei ritsubun (the tax system where two-tenth of the tax delivered from the provinces to the Ministry of Finance at Heian-kyo [the ancient capital of Japan in current Kyoto] were supplied to the tax storage called "ritsubun-do")' that made up the shortage of shozei with the interest on kugaito and establishment of 'shozei shikisu' in which kokushi's minimum liability for shozei suiko (compulsory loaning to and collecting repayments from peasants) was prescribed in kyakushiki (a kind of law in the ritsuryo system).
そこで平安時代に入ると、朝廷も公廨稲の利息より正税の不足分を補わせる「正税率分」の導入や格式に必要最低限の正税出挙に対する国司の支出義務（農民への強制的な貸付強制と徴収（返済）の義務化）を定めた「正税式数」を規定するなど、中央への上供体制維持を目的とした正税回復政策を取り始めた。