Kanto Kanrei was an important post to assist Kamakura kubo (Governor-general of the Kanto region) at Kamakura Government, the regional office of Muromachi bakufu (Japanese feudal government headed by a shogun), and it is said that he assumed office as Kanto Kanrei at the age of 10 due to the death of Norimoto in 1419, and it is confirmed that he took office of Kanto Kanrei in the next year, 1420.
関東管領は室町幕府の出先機関の鎌倉府において、鎌倉公方を補佐する要職で、1419年に憲基が没したため10歳で関東管領に就任したとされており、翌1420年には就任が確認できる。