The change was not ordered (much less asked) by Ieyasu, but done by the Edo clan voluntarily according to the common sense. Samurai clans took their myōji (family name) after the land they owned, and even after they relinquished it, their descendants viewed their myōji no chi (land of myōji) with special feelings. In this case, it was very offensive for the Edo clan to retain their myōji, because it would have suggested that they still had a desire to get back the land. On the other hand, Ieyasu had no reason to give way to one of his tiny vassals who was an enemy until yesterday. For the same reason, no daimyo claimed the title Musashi no kami while the Tokugawa were seated in the province.

In East Asia, it was considered rude to mention someone by his imina (given name). This tradition is called bìhuì in Chinese and hiki in Japanese. The taboo was not so strict about myōji, but people carefully avoided using the word Tokugawa (let alone Ieyasu) under their reign. They called Ieyasu Ōgosho sama while he was in Sunpu, and Gongen sama after his death. His branch families allowed to bear his myōji Tokugawa were also not so called but by their locations: Owari dono, Kishū dono, Mito dono, Tayasu dono, Hitotsubashi dono and Shimizu dono. If the city had been renamed Tokugawa, people would have had trouble just referring to the city.