Lifespan: Bunmei 8 (1476) to 9/29 of Eishō 10 (1513)
Lord: Ōgigayatsu-Uesugi Sadamasa → Yamanouchi-Uesugi Akisada → Ōgigayatsu-Uesugi Tomoyoshi
Father: Ōta Dōkan
Adopted Siblings: Suketada, Sukekatsu (son of Suketada), Sukeie
Wife: [Formal] Daughter of Miura Yoshiatsu
Children: Sukeaki, Suketaka, Sukesada
Ōta Sukeyasu served as a bushō during the Sengoku period. He was a retainer of the Ōgigayatsu-Uesugi family and served as the lord of Edo Castle in Musashi Province.
In 1476, Sukeyasu was born as the lineal heir of Ōta Dōkan (Sukenaga).
In 1485, Sukeyasu attended his coming-of-age ceremony at the Hirakawa-Tenman Shrine on the west side of Edo Castle. Around this time, the relationship between his father, Dōkan, and his lord, Uesugi Sadamasa, deteriorated so Sukeyasu was tendered in the form of a hostage to Ashikaga Shigeuji, the Koga kubō.
In 1486, Dōkan was assassinated by Sadamasa’s retainers at the Kasuya residence in Sagami where Dōkan had served under Sadamasa. Sukeyasu subsequently returned to Edo Castle and inherited the headship of the clan but was pursued by followers of Sadamasa so he fled to Kai Province. This event is known as the Edo Castle Incident.
In 1488, after an internal conflict between Sadamasa and Uesugi Akisada of the Yamanouchi-Uesugi family erupted into the Chōkyō Conflict, Sukeyasu joined Miura Takahira (Sadamasa’s older brother who was also under pursuit) to join the army of Akisada. Through this connection, Sukeyasu later wed the Takahira’s granddaughter (the daughter of Miura Yoshiatsu). Around this time, a monk named Banri Shūku who was a close friend of Dōkan while Dōkan was alive visited Sukeyasu and held a gathering of haiku poets.
In the tenth month of 1494, Sadamasa died while on deployment in Takamihara in Musashi, either as a result of a sudden illness or after falling from a horse while attempting to cross the Ara River. There is a legend that the ghost of Dōkan caused him to fall. After Sukeyasu’s father-in-law, Yoshiatsu, forcibly took over the headship of the Sagami-Miura clan, Sukeyasu was permitted to return to serve Uesugi Tomoyoshi, the new head of the Ōgigayatsu-Uesugi family. Initially, he was assigned to Sugaya Castle in the Obusuma District of Musashi, but, around 1505 after the Chōkyō Conflict came to an end, he returned to Edo Castle.
In 1513, after Yoshiatsu was attacked by Ise Sōzui (Hōjō Sōun), Sukeyasu rushed forward with reinforcements, but was killed in action during a clash with the Hōjō forces in the Miura District of Sagami. According to one theory, he was murdered by his lord, Tomoyoshi, who felt threatened by the power wielded by Sukeyasu. There are also different opinions whether this occurred in 1498 or 1505.