Lifespan: 14xx to 8/26 of Meiō 3 (1494)
Title: Governor of Shinano
Lord: Ashikaga Mochiuji → Uesugi Sadamasa
Father: Ōmori Yoriharu
Siblings: Noriyori, Ujiyori, Takayori, Miura Tokitaka (brother-in-law)
Wife: Daughter of Miura Takaaki
Children: Saneyori, Fujiyori, daughter (wife of Miura Takahira)
Ōmori Ujiyori served as a bushō during the late Muromachi and Sengoku periods. He was the head of the Ōmori clan and a retainer of the Ōgigayatsu-Uesugi family. Ujiyori served as the lord of Odawara Castle, and, later, as the lord of Iwahara Castle in Sagami Province.
Ujiyori’s year of birth is uncertain, but his father, Ōmori Yoriharu, entered the priesthood in 1422, so it is surmised he was born prior to that year.
Initially,Ujiyori followed his older brother, Ōmori Noriyori, to serve Ashikaga Mochiuji, the fourth Kamakura kubō, participating on the side of Mochiuji in the Eikyō Conflict in the Kantō occurring in 1438. After the death of Mochiuji, the Ōmori clan maintained its power. However, from the time of the Kyōtoku War which ran from 1455 to 1483, Ujiyori and his eldest son, Ōmori Saneyori, affiliated with the Uesugi family and were commended by Ashikaga Yoshimasa (the eighth shōgun of the Muromachi bakufu who sided with the Uesugi against Ashikaga Shigeuji – the fifth Kamakura kubō and first Koga kubō) for their years of loyalty. Ujiyori was repeatedly requested to pay a visit to Kyōto, but the Ōmori clan had a deep relationship with the Kamakura kubō, making tenuous their relations with the Muromachi bakufu. Moreover, Ujiyori’s older brother, Noriyori and Noriyori’s son, Shigeyori, supported Ashikaga Shigeuji. Consequently, the Ōmori clan was divided in their support for different sides of the conflict.
Through the assistance of Ōta Dōkan, in 1464, Ujiyori followed him to Kyōto and received a pardon from Yoshimasa. In the fifth month of 1478, Ujiyori joined an assault against Ōmori Izu-no-kami (considered to be Shigeyori) at Hiratsuka Castle in Sagami. After Izu-no-kami fled into the mountains of Hakone, the Ōmori clan was reunified and Ujiyori became the head of the clan. Around this time, Ujiyori entered Odawara Castle and served Uesugi Sadamasa. Together with Ōta Dōkan, Ujiyori served as a senior retainer of the Ōgigayatsu-Uesugi family supporting Sadamasa.
After entering Odawara Castle, Ujiyori endeavored to establish the site as his base of operations. In 1441, he built the Kaizō Temple in Hayakawa and, in 1445, the Sōsei Temple in Kuno in Sagami. He invited Tsuda Oribe Tadamasa to Ōkubo and endeavored to form markets and groups of locals with shared occupations, solidifying his governance of the western portion of Sagami. He also had exchanges with a well-known monk from Kamakura named Gyokuin Eiyo. In 1489, they became acquainted when he came to Yumoto in Hakone for to convalesce in the hot springs and Eiyo recited kanshi, or classical Chinese poetry.
Following the assassination of Ōta Dōkan, Ujiyori was relied upon as the most senior retainer in the Ōgigayatsu-Uesugi family. During the Chōkyō Conflict, at the Battle of Sanemakibara, the Battle of Sugayabara, and the Battle of Takamihara, Ujiyori (serving under the name of Ōmori Kiseian Nyūdō) contributed on a par with Nagao Kageharu and others. Meanwhile, the actions of Sadamasa, including entering into and soon thereafter breaching a settlement with Ashikaga Shigeuji (the Koga kubō), caused retainers to leave the clan. Out of concern for the future of the Ōgigayatsu-Uesugi family, Ujiyori sent Sadamasa a written censure called the Ōmori Precepts.
Ujiyori was knowledgeable in regard to Buddhist sutras. His posthumous Buddhist name has connections to the Nichiren sect, but he also built and ardently protected temples for the Sōtō school of Buddhism. Reflecting his high-level of involvement in multiple sects of Buddhism, he further established relations with the Shingon sect at the Hakone Shrine and the Rinzai sect based at the Jōko Temple, facilitating the governance of his territory. Later, he transferred Odawara Castle to his eldest son, Ōmori Saneyori, and, after adopting the name of Kiseian, moved to Iwahara Castle. When Ujiyori died in 1494, he was preceded in death by Saneyori so his second son, Ōmori Fujiyori, succeeded him as the head of the clan.