Even considering that some of his character evaluations are distorted and inconsistent in order to justify the Tokugawa shogunate, his contributions are undeniable and he introduced a convincing periodization of Japanese history for the first time and made it possible to write a political history.
徳川幕府を正当化するために人物評価が偏っていたり矛盾していたりする点をふくめても、日本史に納得できる時代区分を最初に導入し、政治史を書くことを可能とした功績は疑えない。