Nitta Masauji

Nitta Masauji (1208–1271) was a mid-Kamakura warrior and gokenin, the fifth head of the Nitta main house and eldest son of Nitta Masayoshi. After his father's unauthorized tonsure in 1244, real power over the Nitta passed to collaterals Serada Yoshisue and Iwamatsu Tokikane.

Masauji recovered his position when Yoshisue's son Serada Yoriuji was exiled to Sado Island. A maternal grandson of Ashikaga Yoshiuji, he took the character uji of his name from an Ashikaga patron, beginning a Nitta naming custom. He died in 1271.