However, starting from about the Heian period, the rank differentiation was developed dramatically in regional society, and actions by a small number of rich peasants, who had accumulated movable assets and achieved stable business to enslave poor peasants who had lost their kubunden (the farm land given to each farmer in the Ritsuryo system) due to failed management became more popular.
しかし平安時代になるころから地域社会での階層分化が激しく進み、資本となる動産を蓄積し、安定経営を成し遂げた少数の富豪百姓が、経営が破綻して口分田を失った零細百姓層を隷属下に収めていく動きが激しくなっていった。