was a samurai general in the service of Tokugawa Ieyasu in the Azuchi-Momoyama period, subsequently becoming a daimyō in early Edo period, Japan. Ōkubo Tadayo was the eldest son of Ōkubo Tadakazu, a hereditary retainer of the Tokugawa clan. He was born in what is now part of the city of Okazaki in Mikawa Province, and accompanied Tokugawa Ieyasu in all of his campaigns, including the Battle of Mikatagahara (1573) and Battle of Nagashino (1575). Nicknamed , he rose to become considered one of Ieyasu's sixteen generals and was entrusted with Futamata Castle in Tōtōmi Province. Upon the assassination of Oda Nobunaga in 1582, Ieyasu expanded his rule into Shinano Province, with Ōkubo Tadayo assigned to managing the campaign from his base at Komoro Castle. After the Battle of Odawara (1590), Ie