In the section "Shugo (provincial military governor) should give high priority to honesty" in "Shodanchiyo" by Kaneyoshi ICHIJO, it is described as "the term of office for kokushi (provincial governor) was four years a term and although the present shugo corresponds to kokushi in the former time, they are equivalent to the Twelve Feudal Lords in the Chunqiu period and the Seven Influential Lords in the Zhanguo period, because they govern and succeed the fief from father to son."
一条兼良の『樵談治要』の「諸国の守護たる人廉直をさきとすべき事」の条に「諸国の国司は一任四ケ年に過ぎず、当時の守護職は昔の国司に同じといへども、子々孫々につたへて知行をいたす事は、春秋の時の十二諸侯、戦国の世の七雄にことならず」とある。