The Daiei Discord was a conflict involving the Shimotsuke-Utsunomiya clan in which a group led by Utsunomiya Tadatsuna (the eighteenth head of the Shimotsuke-Utsunomiya clan) clashed with the Haga clan led by Haga Takatsune, a retainer of the Shimotsuke-Utsunomiya clan. The conflict occurred during the Daiei era (1521-1528) in the early Sengoku period.
In 1477, Utsunomiya Shigetsuna (the seventeenth head of the Shimotsuke-Utsunomiya clan) reorganized his group of retainers. After overcoming a major disturbance within the Utsunomiya clan known as the Eishō Insurrection, he rapidly gained power by intervening in the internal affairs of the Koga administration, supporting Ashikaga Takamoto (his son-in-law) to serve as the next Koga kubō, and proactively engaging in military actions while forging alliances with local families of influence through political marriages. Shigetsuna was responsible for rejuvenating the Shimotsuke-Utsunomiya clan from a downward spiral and defeated allied forces comprised of local powers such as Satake Yoshikiyo in the Battle of Takebayashi in 1514 and the Battle of Nawazuri in 1516, attaining control over northern Kantō.
Shigetsuna’s authority extended to Shimotsuke, Hitachi, and Shimōsa provinces, and in the course of his ambitious rise created a large power vacuum by subduing Ashikaga Takamoto, Yūki Masatomo, Nasu Sukechika, Oda Shigeharu and his son. In 1516, however, Shigetsuna died of illness.
Around the time of Shigetsuna’s death, a dramatic change occurred in relations with influential families in the local area. Nasu Sukechika of one faction of the Nasu clan had joined with Shigetsuna in support of Ashikaga Takamoto in the course of a power-struggle between Takamoto and Ashikaga Masauji known as the Eishō Disturbance, but the death of Sukechika in 1514 triggered a succession struggle that led to the demise of the clan. Shigetsuna had members of the Utsunomiya succeed Sukechika and aimed to revive the family, but was unable through Nasu Sukefusa to unify two factions of the Nasu family.
After the demise of Shigetsuna, Yūki Masatomo of the Yūki clan plotted to capture twelve neighborhoods in the former territory of the Utsunomiya, descending into a confrontational relationship with the Utsunomiya. Meanwhile, Satake Yoshikiyo of the rival Satake clan died in 1517 and was succeeded by Satake Yoshiatsu became the head of the clan and formed an alliance with Oda Masaharu. Masaharu feared the rapid expansion of influence by Hōjō Ujitsuna in the southern portions of the Kantō.
Confrontation between Utsunomiya Tadatsuna and the retainers
In 1512, Shigetsuna planned for Utsunomiya Tadatsuna to become his successor and the eighteenth head of the Shimotsuke-Utsunomiya clan. Following the death of Shigetsuna from illness in 1516, Tadatsuna became the new head of the clan in form and in substance. In accordance with the will of his father, Tadatsuna expanded the influence of the clan and reinforced control over his retainers. Tadatsuna, however, did not achieve the results of his esteemed father, while his strong-arm tactics to assert control bred dissatisfaction among his retainers. In addition to opposing Tadatsuna’s attempts to govern, the retainers resented Mibu Tsunashige and his son, Mibu Tsunafusa, who became a rising power after the Utsunomiya Disturbance (an internal rebellion in the Utsunomiya clan that ran from 1512 to 1516). Retainers further took issue with the treatment of the Haga clan, in particular, Haga Takataka and Haga Takatsune, who were held in Utsunomiya Castle after the Utsunomiya Disturbance.
Shionoya Takatsuna, Tadatsuna’s uncle and clan elder, was appointed as the representative to govern the territory of the Haga clan. However, members of the Utsunomiya clan including Takatsuna, along with Kasama Suketsuna and his son, Kasama Tsunahiro, objected to this arrangement and sided with the Haga clan against Tadatsuna. Meanwhile, Mibu Tsunafusa and Nagayama Tadayoshi supported Tadatsuna, leading to a split among the retainers into two factions. The confrontation between the Utsunomiya and Mibu on one side and the Haga and Shionoya on the other arose again in the Tenmon Insurrection.
The Battle of Saruyama
Haga Takatsune visited Yūki Castle to solicit support from Yūki Masatomo. Masatomo considered it to be a good opportunity to recapture their former territory from the Utsunomiya. In the eighth month of 1523, under the pretext of cooperating with the Haga clan, the Yūki invaded the territory of the Utsunomiya in Shimotsuke Province. The invading forces clashed with the Utsunomiya army on Mount Saru in an event known as the Battle of Saruyama. The Yūki prevailed in the battle and Tadatsuna was ousted from Utsunomiya Castle. Yūki Masatomo and the faction opposed to Tadatsuna led by Haga Takatsune backed Utsunomiya Okitsuna, the youngest child of Shigetsuna, as the nineteenth head of the Utsunomiya clan. The youthful Okitsuna, along with Tadatsuna, were both sons of Shigetsuna. His mother was a member of the branch of the Ashikaga family that served as the Koga kubō. She was the daughter of Uesugi Akizane who served as the twelfth head of the Yamauchi-Uesugi clan and the deputy shōgun of the Kantō. In terms of lineage, she was on par with the head of the Utsunomiya clan.
The ouster of Tadatsuna also drew the attention of forces in northern Kantō such as Satake Yoshiatsu.
Aiming for a revival from Kanuma Castle
Tadatsuna fled from Utsunomiya Castle to seek the aid of a senior retainer, Mibu Tsunafusa, at Kanuma Castle. Following the ouster of Tadatsuna, the retainers who supported him such as Nagayama Tadayoshi escaped from Shimotsuke Province. The ouster of Tadatsuna and stiff opposition by the anti-Tadatsuna faction against his supporters such as the Mibu clan had serious consequences for the area. From 1523 to 1524, a series of violent battles occurred in the Utsunomiya domain and surrounding areas between those retainers for and against Tadatsuna. Based in Kanuma, Tadatsuna maintained close communications with Ashikaga Takamoto, the Koga kubō, and aimed to return to Utsunomiya Castle. He failed to achieve his goal after dying on 7/16 of 1527. Under one theory, Mibu Tadafusa abandoned Tadatsuna, colluded with the faction opposed to Tadatsuna, and was killed. Upon the death of Tadatsuna, the insurrection came to an end.
Thereafter, the Haga clan reclaimed their authority and enjoyed the peak of their prosperity since the time that Haga Kagetaka served as a trusted confidant of Shigetsuna. In fact, however, the leadership of the Utsunomiya became puppets of its retainers and, as a result, the Shimotsuke-Utsunomiya clan fell into sharp decline, losing the status attained under Shigetsuna as the preeminent power in northern Kantō. Similarly, for the Yūki, the Satake, and the Oda clans, stability under the influence of their retainers came at the expense of falling behind in terms of their influence, making them susceptible to invasion by neighboring powers. Members of the Utsunomiya such as the Mumo and the Matsuno clans left their former lords and pledged allegiance to the Satake clan, a rising power. While the Utsunomiya witnessed a hollowing out of leadership, after his coming-of-age ceremony, Utsunomiya Okitsuna entered into conflict with Haga Takatsune and Mibu Tsunafusa over policy differences and was compelled to take his own life. Afterwards, the second son of Shigetsuna, Utsunomiya Toshitsuna, became the head of the clan. Toshitsuna proactively tried to restore authority, which actions led to the Tenmon Insurrection.
In addition to the Daiei Insurrection, other significant events involving the Utsunomiya can during the Sengoku period included the Eishō Conflict and the Tenbun Rebellion. Among these events, in particular, the Daiei Discord had a major influence on the future course of events, causing the retainers to act with abandon, and served as a primary reason for the vulnerability of the Utsunomiya when later confronted by the Gohōjō clan.