The political, military and economical base was Kanto chigyo-koku (provincial fiefdom) and Kanto domains which Yoritomo acquired by searching out and destroying the Taira clan and its allies, but the essence was the lower-ranking vassal system whose base was a feudal master-servant relationship between Kamakura-dono and gokenin (an immediate vassal of the shogunate in the Kamakura and Muromachi through Edo periods).
その政治的基盤及び軍事的・経済的基盤は頼朝が平氏追討などで獲得した関東知行国、関東御領であるが、その本質は鎌倉殿と御家人の封建的主従関係を基礎とする御家人制にある。