Lifespan: 14xx to 15xx
Other Names: Mutō Masauji
Title: Junior Fifth Rank (Lower), Master of the Western Capital Office
Father: Daihōji Takeuji
Children: Sumiuji, 氏説, Kurō
Daihōji Masauji served as a bushi during the late Muromachi period. Masauji was the twelfth head of the Daihōji clan of Dewa Province. He was the steward of Mount Haguro which, along with Mount Gassan and Mount Yudono, was one of the three sacred mountains of Dewa for the Shintō religion and for practitioners of the mountain ascetic cult known as shugendō. Hosokawa Masamoto was an adherent of this form of religion.
Masauji was born as the son of Daihōji Takeuji, a bushi from the late Muromachi period. He received one of the characters from the name of Ashikaga Yoshimasa, the eighth shōgun of the Muromachi bakufu, and adopted the name of Masauji.
In 1472, after inheriting the headship of the clan, Masauji offered to Ise Sadamune (the official in charge of the mandokoro, an office for the administration of domains and general affairs of influential noble families) coins in the amount of 1,000 hiki, two horses, and other gifts, for which he then received in return a long sword crafted by Kunimune (a sword-maker in Bizen Province during the mid-Kamakura period), a scabbard adorned with gold, porcelain rice bowls, safflower, tea, a Tsukushi bow (from northern Kyūshū), and other gifts. Sadamune sent a letter on the same date to Tosabayashi Kunai-Shōyū to give thanks for the delivery of three horses promised in the prior year whereupon he sent an incense box and incense burner, a tray made of yew plum pine, a vase, tiger fur, a pouch for flint, a folding fan, and other gifts.
In the midst of Masauji’s expanding his influence, the Tosabayashi clan transferred to him the official role of bettō, or steward of the religious institutions on Mount Haguro. While fostering the authority of these shrines, Masauji succeeded in gradually deepening his own influence. Masauji later came into conflict with the Sagoshi clan who served as the governors of the Akumi District in Dewa. After the head of the Sagoshi clan, Sagoshi Ujitaka, was conferred the title of Governor of Shinano, Masauji protested and then was granted the Court titles of Junior Fifth Rank (lower) and Master of the Western Capital Office.
After his demise, Masauji was succeeded by his son, Daihōji Sumiuji.