[8] Matsudaira Nobumitsu (15th century), son of Chikauji, was in charge of Okazaki Castle, and strengthened the authority of his family in the Mikawa province.

This decision was made after he counseled by his senior vassal Sakai Tadatsugu to abandon their allegiance with the Imagawa clan.

[12] He also strengthened his powerbase by creating a military government system of Tokugawa clan in Mikawa which based from his hereditary vassals Fudai daimyō.

The system which called "Sanbi no gunsei" (三備の軍制) with the structure divide the governance into three sections:[13][14][15] To the end of the Edo period they ruled Japan as shoguns.

[citation needed] After the death of Ieyasu, in 1636, the heads of the gosanke (the three branches with fiefs in Owari, Kishū, and Mito) also bore the Tokugawa surname, so did the three additional branches, known as the gosankyō: the Tayasu (1731), Hitotsubashi (1735), and Shimizu (1758) family, after the ascension of Tokugawa Yoshimune.

Once a shogun died without a living heir, both the heads of gosanke (except Mito-Tokugawa family) and gosankyō had priority to succeed his position.

[20] The 1946 Constitution of Japan abolished the kazoku and the noble titles, making Iesato's son, Iemasa Tokugawa, no longer a prince.

[23] Tsunenari formed the Tokugawa Memorial Foundation in 2003 to preserve and administer the historical objects, art, armor and documents that have been passed down in the Tokugawa family over the generations, display them for the general public and provide assistance to academic research on topics concerning historical Japan.

The Tokugawa's clan symbol, known in Japanese as a "mon", the "triple hollyhock" (although commonly, but mistakenly identified as "hollyhock", the "aoi" actually belongs to the birthwort family and translates as "wild ginger"—Asarum), has been a readily recognized icon in Japan, symbolizing in equal parts the Tokugawa clan and the last shogunate.