Tadasuke was a younger brother of Okubo Tadayo. He fought in a number of notable battles for Tokugawa Ieyasu (including Mikatagahara and Nagashino) and came to hold Numazu han, in Suruga province, in 1601, with a kokudaka of 20,000 koku. He died without heirs in 1613.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005
- Cesare Polenghi, Samurai of Ayutthaya: Yamada Nagamasa, Japanese warrior and merchant in early seventeenth-century Siam. Bangkok: White Lotus Press (2009), 13.