- Born: 1503
- Died: 1559
- Titles: Saemon no kami
- Distinctions: lord of Shimosa province
- Japanese: 結城政勝 (Yuuki Masakatsu)
Masakatsu was the son of Yûki Masatomo (1477-1545) and assumed leadership of the Yûki around 1525. He clashed with local powers such as the Oda and composed the Yûki House Code (Yûki-shi shin hatto) in 1556. He died in September 1559 and was succeeded by his nephew Harutomo, who he had adopted as his son and heir.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005