Fudai daimyō (譜代大名) was a class of daimyō (大名) in the Tokugawa Shogunate (徳川幕府) of Japan who were hereditary vassals of the Tokugawa before the Battle of Sekigahara. Fudai daimyō and their descendants filled the ranks of the Tokugawa administration in opposition to the tozama daimyō and held most of the power in Japan during the Edo period.