Masatsuna was a son of Okabe Hisatsuna. He first served Imagawa Ujizane, then joined the Takeda after 1569. He fought in a number of battles with the Takeda, including Mikatagahara (1573) and Takatenjin (1574) but became a ronin after their fall in 1582. Not long afterwards he entered the service of the Tokugawa but died in 1583.
References
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005