Andō yūichirō (2022). "だから織田と豊臣はあっさり潰れた…徳川家康が｢戦国最後の天下人｣になれた本当の理由" [The reason why Oda and Toyotomi were easily defeated... Tokugawa Ieyasu was the "last of the Sengoku period."]. President Online (in Japanese). PRESIDENT Inc. pp. 1–4. Retrieved June 4, 2024.
Historian Adam Sadler saw this step as the riskiest move Ieyasu ever made—to leave his home province and rely on the uncertain loyalty of the formerly Hōjō clan samurai in Kantō. In the end however, it worked out brilliantly for Ieyasu. He reformed the Kantō region, controlled and pacified the Hōjō samurai and improved the underlying economic infrastructure of the lands. Also, because Kantō was somewhat isolated from the rest of Japan, Ieyasu was able to ally with daimyos of north-east Japan such as Date Masamune, Mogami Yoshiaki, Satake Yoshishige and Nanbu Nobunao; he was also able to maintain a unique level of autonomy from Toyotomi Hideyoshi's rule. Within a few years, Ieyasu had become the second most powerful daimyo in Japan. It was said by anecdotal proverb that: "Ieyasu won the Empire by retreating."[44] Historian Watanabe Daimon stated that the general opinion was that Ieyasu was reluctant about his transfer to Kantō. However, Daimon stated that thinking Ieyasu was reluctant was an opinion of a later era. Daimon suspected that Ieyasu actually saw this transfer positively as he realised a huge undeveloped potential by making Edo as his seat of power.[45] Historian Andō yūichirō further added, the true intention of Hideyoshi transferring Ieyasu to Kantō was to weaken the power of the Tokugawa clan by moving them from their ancestral land in Mikawa, as he expected the former Hōjō vassals in Kantō would rebel against Ieyasu. However, this backfired as Ieyasu not only doubled the territories he control, but he also further added the bulk of new vassals in Kantō to the already impressive political and military power of Tokugawa regime as they already absorbed the army of Imagawa clan and Takeda clan before.[9]
