Date: Chōkyō 1 (1487) to Eishō 2 (1505)
Location: The Kantō region, in particular, Musashi, Sagami, Shimotsuke, and Izu provinces
Synopsis: This extended conflict between the Yamanouchi-Uesugi and the Ōgigayatsu-Uesugi branches ultimately weakened the clan to an extent that allowed the Hōjō clan led by Hōjō Sōun to wrest control of most of the Kantō away from the rival Uesugi clan.
Head of family: Uesugi Akisada
Relatives: Uesugi Fusasada (father), Uesugi Fusayoshi (younger brother) – military governors of Echigo Province; Uesugi Norifusa (adopted son), Uesugi Akizane (adopted son)
Koga kubō family: Ashikaga Shigeuji, Ashikaga Masauji, Ashikaga Masatomo
Base of Operations: Hachigata Castle in Musashi Province
Head of family: Uesugi Sadamasa – succeeded by his son, Uesugi Tomoyoshi
Key Allies: Imagawa Ujichika, Hōjō Sōun, Nagao Kageharu (rebelled against Akisada), Miura Tokitaka, Ōmori Ujiyori
Base of Operations: Kasuya residence in Sagami Province; Kawagoe Castle in Musashi Province
The Chōkyō War (Chōkyō no ran) persisted from 1487 to 1505 between two branches of the Uesugi clan – the Yamanouchi-Uesugi and the Ōgigayatsu-Uesugi. The Yamanouchi-Uesugi family were led by Uesugi Akisada and served as the deputy shōgun of the Kantō. The Ōgigayatsu-Uesugi were led by Uesugi Sadamasa (and, after his demise, his nephew, Uesugi Tomoyoshi). The conflict ultimately led to the decline of the Uesugi clan, providing an opportunity for the Hōjō clan led by Hōjō Sōun to seize control over a majority of the Kantō.
As a prelude to the Chōkyō War, the Kyōtoku War (Kyōtoku no ran) between the Uesugi clan and Ashikaga Shigeuji (the Koga kubō) ran from 1455 to 1483. The members of the Uesugi branches joined forces in a series of battles against Shigeuji who was supported by assorted daimyō in the Kantō. In 1476, discord between Uesugi Akisada and a senior commander named Nagao Kageharu caused Kageharu to launch a rebellion, known as the Revolt of Nagao Kageharu, resulting in a total collapse of the Yamanouchi-Uesugi army. Ōta Dōkan, the head of house affairs for the Ōgigayatsu-Uesugi family, suppressed the rebellion.
Notwithstanding Dōkan’s success in halting Kageharu’s rebellion, the authority of Akisada (the deputy shōgun of the Kantō) and the Yamanouchi-Uesugi family suffered a decline while Dōkan’s lord, Uesugi Sadamasa of the Ōgigayatsu-Uesugi family, gained influence. Although Sadamasa had once lamented a mocking caricature of the Ōgigayatsu-Uesugi family as a little bird compared to the stature of the Yamanouchi-Uesugi as a big bird, these developments elevated the Ōgigayatsu-Uesugi to a level of influence comparable to the Yamanouchi-Uesugi.
Fearing the situation, Akisada sought to raise Sadamasa’s suspicions by warning him that the resourceful Dōkan would eventually threaten the Uesugi clan. Akisada then made efforts to reconcile with Ashikaga Shigeuji (the Koga kubō) while secretly planning for battle against Sadamasa. Over time, Sadamasa distanced himself from Dōkan, while Dōkan himself began to fear Sadamasa’s failure to recognize his loyalty. Out of caution, Dōkan sent his son, Ōta Sukeyasu, as a hostage to Shigeuji.
In 1486, Dōkan was assassinated by Sadamasa’s retainers at the Kasuya residence in Sagami where Dōkan had served under Sadamasa. Thereafter, Sukeyasu returned to Edo Castle and succeeded his father as head of the family. Sadamasa then soon expelled Sukeyasu and occupied Edo Castle in an event known as the Edo Castle Incident (Edojō no ran). The intentional killing of Dōkan who had served as a trusted pillar inside and outside of the family shook the Ōgigayatsu. In particular, Miura Takahira, head of the Miura clan of Sagami and the older brother of Sadamasa, plotted to overthrow Sadamasa, and instead was banished by the former head of the clan, Miura Tokitaka.
In 1487, Uesugi Akisada and Uesugi Sadamasa (his older brother and military governor of Echigo) seized Kannō Castle located in the Ashikaga manor in Shimotsuke Province. Kannō had been occupied by Nagao Fusakiyo who had been colluding with the Ōgigayatsu-Uesgui family, so the seizure triggered a battle between the Yamanouchi-Uesugi and the Ōgigayatsu-Uesugi.
Course of Events
In 1488, Akisada received support from Uesugi Fusasada (his father and military governor of Echigo). Akisada, along with Ōta Sukeyasu and Miura Takahira, departed with 1000 mounted soldiers from his base at Hachigata Castle in Musashi Province and at once aimed to gain control of Sadamasa’s headquarters at the Kasuya residence. Sadamasa had left his older brother, Uesugi Tomomasa (the father of Tomoyoshi – Sadamasa’s adopted son) to defend Kasuya while Sadamasa sojourned at Kawagoe Castle in Musashi. With only 200 mounted soldiers, Sadamasa gave chase and launched a surprise attack against Akisada’s army at Sanemakihara in the environs of the Kasuya residence. The unexpected attack crushed Akisada’s forces, but Tomomasa lost Nanasawa Castle. Soon thereafter, Tomomasa took his own life at Shiroi Castle in Kōzuke Province in advance of an assault by the Ōgigayatsu-Uesugi clan and Nagao Kageharu.
An indignant Akisada then attacked Kawagoe Castle, but, on this occasion, Nagao Kageharu (who had earlier rebelled against Akisada and fled) led reinforcements provided by Ashikaga Masauji (the son of Shigeuji who inherited the role of Koga kubō after Shigeuji’s retirement) and joined with Sadamasa’s army. The forces collided at Sugayahara, and Sadamasa’s army repelled Akisada’s army. Toward the end of the year, Sadamasa’s army attacked Hachigata Castle, causing Akisada’s army to confront them at Takamihara and Takanohara, but Akisada’s men suffered a defeat.
The clashes between the Yamanouchi-Uesugi and the Ōgigayatsu-Uesugi at Sanemakihara, Sugayahara, and Takamihara (including Takanohara) are referred to as the Three Battles of Chōkyō. All three ended in victory for the Ōgigayatsu-Uesugi forces, but, after the intentional killing of Ōta Dōkan, the estrangement of military staff continued. Meanwhile, the Yamanouchi-Uesugi forces had the backing of allies in Echigo and Kōzuke provinces, and with this support, continued to hold on to Hachigata Castle.
During these conflicts, Ashikaga Masatomo (who the Uesugi clan had invited to serve as the Kamakura kubō in place of Ashikaga Shigeuji) was unable to enter Kamakura. Instead, he established his base in Izu Province for which the Yamanouchi-Uesugi served as the military governor, and adopted the name of the Horigoe kubō. The Uesugi clan and the Koga kubō reached a critical settlement so Izu became the only province under control of the Horigoe kubō. Masatomo then died of illness in 1491.
Following the demise of Masatomo, an internal conflict arose within the Horigoe kubō. In 1493, Ise Sōzui (later known as Hōjō Sōun, who was serving as lord of Kōkokuji Castle and as a guest commander of the Imagawa clan of Suruga Province), took advantage of the turmoil in the wake of Masatomo’s demise to attack and seize control of Izu Province. This occurred under orders from Ashikaga Yoshitō (later known as Ashikaga Yoshizumi), who originated from the family of the Horigoe kubō and became the eleventh shōgun of the Muromachi bakufu the following year. This plan may have further been orchestrated by Uesugi Sadamasa, who regarded the presence of the Horigoe kubō and the Yamanouchi-Uesugi forces who supported them in Izu as a threat to his territory in Sagami. In fact, immediately after this event, Sadamasa made a request to Sōun to cooperate in a campaign to oust Akisada.
Nevertheless, in 1494, Sadamasa’s proxies who governed the eastern and western portions of Sagami (Ōmori Ujiyori of Odawara Castle (8/16) and Miura Tokikata of Misaki Castle (9/23)) died one after another whereupon the Miura and Ōmori clans both endured succession struggles. On 10/2, Uesugi Sadamasa then turned to reinforcements from Hōjō Sōun and deployed to Takamihara again in a bid to defeat Uesugi Akisada of Hachigata Castle, but fell from his horse while attempting to cross the Ara River and died. Uesugi Tomoyoshi succeeded him as head of the Ōgigayatsu-Uesugi family, but Sadamasa’s death had a significant impact on the course of the conflict.
Ashikaga Shigeuji, the Koga kubō, had experienced a deteriorating relationship with Sadamasa, so after Sadamasa’s unexpected demise, Shigeuji aligned himself with Akisada. Meanwhile, within the Miura clan of Sagami, Miura Yoshiatsu (the adopted son of Miura Takahira) prevailed in the succession struggle and became the next head of the clan. As a result, Takahira (his father) and Ōta Sukeyasu (his son-in-law) returned to the Ōgigayatsu-Uesugi family upon the good word of Yoshiatsu. Akisada’s father, Uesugi Fusasada, the military governor of Echigo, died of illness on 10/17 and Akisada’s younger brother, Uesugi Fusayoshi, succeeded him.
In 1495, Hōjō Sōun executed a scheme to seize Odawara Castle from Ōmori Fujiyori after Fujiyori became head of the Ōmori clan. However, in 1496, Akisada combined forces with Ashikaga Masauji, invaded Sagami, and engaged in battle against Nagao Kageharu, Ōmori Fujiyori, and reinforcements from Hōjō Sōun on behalf of the Ōgigayatsu-Uesugi family. The invading forces toppled Odawara Castle defended by Ōmori Fujiyori and reinforcements led by Hōjō Yajirō (the younger brother of Sōun). After Sōun earlier captured Odawara Castle, Fujiyori should have been banished. Instead, Fujiyori had remained as its lord based on support from Sōun as his sworn friend. For some reason, until 1501, Sōun received permission from Uesugi Tomoyoshi (the military governor of Sagami) to occupy Odawara Castle and treat it as his own.
Notwithstanding the allied relationship, assigning a portion of territory to the retainers of a daimyō of another province reflected the dire military situation confronted by Tomoyoshi. Tomoyoshi needed Sōun not only for his military acumen, but also for the military support of Imagawa Ujichika, the military governor of Suruga who served as Sōun’s guardian. In fact, with the military support of Sōun, Tomoyoshi succeeded in recovering several castles in Sagami that had earlier been captured by Akisada. As a result, the front lines of the conflict returned to Musashi Province.
On 8/22 of 1504, Akisada initiated an attack against Tomoyoshi’s base at Kawagoe Castle, but once this turned into a stalemate, he directed the forces toward Edo Castle in the south. However, en route, Akisada received information that Hōjō Sōun had combined with Imagawa Ujichika and were marching toward Musashi Province, so he gathered forces at Tachikawahara in Musashi. On 9/27, allied forces of Uesugi Akisada and Ashikaga Masauji collided with the allied forces of Uesugi Tomoyoshi, Imagawa Ujichika, and Hōjō Sōun at Tachikawa-no-hara. In this Battle of Tachikawa-no-hara, Akisada suffered a major defeat and lost over 2000 soldiers.
Upon hearing the news, Uesugi Fusayoshi (Akisada’s older brother and the military governor of Echigo) attempted to provide support, dispatching Nagao Yoshikage (the deputy military governor) from Hachigata Castle. The withdrawal from Kawagoe Castle of reinforcements from the Imagawa and Hōjō created an opportunity to attack, and with that momentum, he toppled Hatsuzawa and Sanada castles. Ironically, the major victory achieved by the Ōgigayatsu-Uesugi at Tachikawa-no-hara invited a large-scale invasion by the Echigo-Uesugi against the Ōgigayatsu-Uesugi family.
In the third month of 1505, Tomoyoshi declared surrender after Akisada’s forces laid siege to Kawagoe Castle for the second time. Akisada incarcerated Tomoyoshi in the Sugaya residence near the former Sugayahara battlefield, and had him enter the priesthood. In lieu of Tomoyoshi, Akisada compelled the Ōgigayatsu-Uesugi retainers to stand behind his nephew, Uesugi Tomooki, to become their new lord. However, the retainers strongly opposed the appointment. Meanwhile, within the family of the Koga kubō, the relationship between Ashikaga Masauji and his eldest son, Ashikaga Takamoto, became strained. These circumstances caused Akisada to change his policy, whereupon Tomoyoshi was released, returned to Kawagoe Castle, and the original plan to replace him deemed never to have existed. In 1507, a political marriage was made between Uesugi Norifusa (an adopted son of Akisada) and the younger sister of Tomoyoshi, restoring the allied relationship between the Yamanouchi-Uesugi and Ōgigayatsu-Uesugi families.
Nevertheless, peace between the families was suddenly broken.
Soon after the political marriage between the Yamanouchi-Uesugi and the Ōgigayatsu-Uesugi families, Uesugi Fusayoshi, the military governor of Echigo Province who was the younger brother of Akisada and served as his righthand man, took his own life following a pursuit by forces under the command of Uesugi Sadazane (who was backed by Nagao Tamekage, the deputy military governor of Echigo). This upset Akisada, who, after recovering his military strength, in 1509, raised arms and marched into Echigo to eliminate Tamekage. In advance of departing, Akisada held discussions with Uesugi Tomoyoshi and exchanged a written promise. Next, Nagao Kageharu, who had returned to the former territory of Kōzuke, sought to take advantage of the absence and rebelled again, while Hōjō Sōun broke the alliance with the Ōgigayatsu-Uesugi family and launched an invasion into central Sagami.
The following year, Akisada was killed in battle by forces under the command of Sadazane and Tamekage. His two adopted sons (Norifusa and Akizane (the nautural son of Ashikaga Shigeuji)) then entered into a succession struggle for the role of the deputy shōgun of the Kantō. Meanwhile, in the Koga kubō family, Ashikaga Masauji endeavored to support Akizane, triggering conflict with Ashikaga Takamoto who opposed the succession. This escalated into an internal dispute regarding the status of the Koga kubō that also involved Takamoto’s younger brother, Ashikaga Yoshiaki. This series of battles is known as the Eishō Conflict. Uesugi Tomoyoshi scrambled in an effort to resolve the internal disputes in the Yamanouchi-Uesugi family and the Koga kubō family, but during this period Hōjō Sōun eliminated the Miura clan and seized control of Sagami Province.
Thereafter, within less than fifty years, the Hōjō clan took over governance from the Uesugi clan of most of the Kantō. The Koga kubō became a puppet administration, with the Chōkyō War serving as its genesis.