Ii clan

Ii clan (井伊氏, Ii-shi) is a Japanese clan which originates in Tōtōmi Province. It was a retainer clan of the Imagawa family, and then switched sides to the Matsudaira clan of Mikawa Province. A famed 16th-century clan member, Ii Naomasa, served as one of Tokugawa Ieyasu's generals, and received the fief of Hikone in Ōmi Province as a reward for his conduct in battle at Sekigahara. The Ii and a few sub-branches remained daimyo for the duration of the Edo period. Ii Naosuke, the famed politician of the late Edo period, was another member of this clan.

The clan claims descent from Fujiwara no Yoshikado, who had been one of the Daijō daijin during the ninth century.