Tadamasa was the eldest son of Honda Tadakatsu. He accompanied Tokugawa Hidetada during the Sekigahara Campaign (1600) and fought at the Osaka castle sieges (1614, 1615). In 1617 he received a 250,000-koku fief at Himeji in Harima province. He was married to a daughter of the by-then late Tokugawa Nobuyasu, Ieyasu's eldest son.
Sons: Honda Tadatoki (1596-1626), Honda Tadayoshi (1602-1676), Honda Masatoki
- Initial text from Samurai-Archives.com FWSeal & CEWest, 2005