He tightened the controls on Daimyo (Japanese feudal lord), by which many Tozama daimyo (a daimyo who was not a hereditary vassal of the Tokugawa family) including Masanori FUKUSHIMA were deprived of their status, and assigned his three younger brothers to the Owari Domain, the Kii Domain and the Mito Domain respectively and gave Suruga Province, Totomi Province and Kai Province to his own son, Tadanaga TOKUGAWA.
大名統制を強化して福島正則ら多くの外様大名を改易し、3人の弟を尾張藩・紀伊藩・水戸藩に配置し、自身の子徳川忠長に駿河国・遠江国・甲斐国を与えた。