Lifespan: 7/12 of Eikyō 7 (1435) to 4/3 of Entoku 3 (1491)
Title: Junior Third Rank, Chief of the Cavalry for the Left Division
Bakufu: First Horigoe kubō of the Muromachi bakufu
Lord: Ashikaga Yoshimasa → Ashikaga Yoshimitsu → Ashikaga Yoshitane
Father: Ashikaga Yoshinori (the sixth shōgun)
Mother: Shōben-dono (from the Saitō clan)
Siblings: Yoshikatsu, Masatomo, Yoshimasa, Yoshimi, other
Wife: [Consort] Enman-in (daughter of Musha-no-kōji Takamitsu)
Children: Chachamaru, Yoshizumi, Masauji, Jundōji, Oda Masaharu (?)
Ashikaga Masatomo served as a bushō during the latter part of the Muromachi period. A member of the Ashikaga shōgun family, Masatomo became the first Horigoe kubō. He was the second son of Ashikaga Yoshinori, the sixth shōgun. His mother, Shōben-dono, originated from the Saitō clan, a military family serving on behalf of the shōgun (known as a hōkōshū). She was the younger sister of Saitō Asahi. Masatomo was the younger half-brother (of a different mother) of Ashikaga Yoshikatsu, the seventh shōgun, and the older half-brother (of a different mother) of Ashikaga Yoshimasa (the eighth shōgun) and Ashikaga Yoshimi (a son of Ashikaga Yoshinori). Masatomo was also the father of Ashikaga Yoshizumi, the eleventh shōgun, and successor shōgun descended from his bloodline.
Masatomo departed from the capital of Kyōto as the Kamakura kubō recognized by the Muromachi bakufu; however, owing to certain factors including chaos in the Kantō Region caused by the Kyōtoku War (Kyōtoku no ran), a decline in the authority of the bakufu, and an internal conflict within the Uesugi clan, Masatomo was unable to enter Kamakura, and, instead, he stopped in Horigoe in Izu Province. Thereafter, he became known as the Horigoe kubō.
Traveling from the capital to the Kantō Region
In 1435, Masatomo was born as the fourth (illegitimate) son of Ashikaga Yoshinori, the sixth shōgun. He was older than Yoshimasa, but treated as a younger brother because Yoshimasa’s mother came from the Hino, a family of a noble lineage who had intermarried with the Ashikaga shōgun family for generations. Masatomo was raised as a monk from an early age, becoming the head of the Kōgen-in, a sub-temple of the Tenryū Temple, and adopting the name of Seikyū.
Late in 1457, Seikyū returned to secular life upon orders of Yoshimasa, receiving one of the characters from Yoshimasa’s name and adopting the new name of Masatomo. Several days later, he departed Kyōto and arrived at Onjōji in Ōmi Province. In the spring of 1458, he was given a flag of conquest and headed toward the Kantō. He then arrived between spring and summer in Horigoe in Izu Province.
Together with Shibukawa Yoshikane (the secretary for Kantō) and Uesugi Noritomo as assistants, Masatomo had been dispatched to serve as the Kamakura kubō with the official sanction of the bakufu as his assistants. However, the prolonged struggle between the bakufu and Ashikaga Shigeuji, the powerful Koga kubō, in the Kyōtoku Conflict prevented Masatomo from entering Kamakura. Consequently, in early summer, he settled in Horigoe in Izu Province. Around the time that Yoshimasa dispatched Masatomo, he ordered daimyō from provinces in the Kantō Region including Mutsu, Dewa, Kai, and Shinano to deploy for a large-scale offensive to overthrow Shigeuji in favor of Masatomo.
Shiba Yoshitoshi, the military governor of Echizen, Owari, and Tōtōmi provinces failed to obey the orders to deploy to Kantō, instead heading toward Echizen to suppress an internal uprising known as the Battle of Chōroku. Owing to these actions, Yoshimasa removed Yoshitoshi from his position in the early summer of 1459, halting the deployment of the Shiba army. In the autumn, the bakufu army stationed in Kantō lost to Shigeuji’s army at the Battle of Ōta-no-shō. This resulted in a collapse of the plan to overthrow Shigeuji and a loss of trust among the daimyō. As a result, Masatomo remained in Izu Province without his own military forces.
Activities as a Horigoe kubō
Early in 1460, Imagawa Noritada, the military governor of Suruga Province, withdrew from Kamakura to return to his home province. In the spring, Masatomo’s base at the Kokusei Temple in Horigoe was burned down by Shigeuji’s forces, after which Masatomo moved to the Horigoe gosho or palace. Rather than overthrow Shigeuji, Masatomo confronted threats to his own life. He sent a messenger to Kyōto to deliberate the response with the bakufu. In the autumn, retainers from the Shiba clan including Asakura Takakage and Kai Toshimitsu, were dispatched, yielding the promise of a military force; however, when Masatomo attempted to move to Kamakura with the backing of the Shiba army, Yoshimasa halted the advance. This is because he feared the Horigoe administration would combine with the Uesugi who served as the bakufu army in the Kantō, enabling the Horigoe kubō to become independent of the bakufu. The bakufu commanded the army, not Masatomo, and the bakufu issued orders to leaders in the region, bypassing Masatomo.
In the autumn of 1461, the head of the Shiba clan changed upon orders of Yoshimasa. Yoshitoshi’s child, Matsuōmaru, entered the priesthood, while Shibukawa Yoshikado, the son of Shibukawa Yoshikane, became the head of the Shiba clan. He was formally appointed after a meeting with Yoshimasa joined by Asakura Takakage and Kai Toshimitsu. Rather than maintain control through the bakufu, Yoshimasa sought to strengthen the military force of the Horigoe administration. Yoshikane served as the secretary for Masatomo, so by having Yoshikane’s son become head of the Shiba clan, the Shiba army came under the direct control of the Horigoe administration. Then, the bakufu in Kantō began to show cracks. Beginning in 1461, retainers of Masatomo seized landholdings of local families in Kamakura and Sagami Provinc, the head of affairs for the Ōgigayatsu family named Ōta Sukekiyo retired, while one of Masatomo’s other lieutenants, Uesugi Noritomo, killed himself for no apparent reason.
In 1462, Masatomo believed slander from Yoshikane. He informed Yoshimasa of a rebellion by Uesugi Mochitomo, the head of the Ōgigayatsu family. This led to a difference of opinion within the Uesugi clan whether to support Masatomo, whereupon Masatomo blocked Mochitomo’s position as the military governor of Sagami and took control of the province. Yoshimasa then ordered Masatomo to protect Mochitomo, escalating into turmoil by which Miura Tokitaka and Chiba Sanetane, senior retainers of Mochitomo, retired. Yoshimasa then personally intervened, resolving the situation by having Mochitomo and others guarantee the standing of the Ōgigayatsu family and ousting Yoshikane from the Horigoe administration for his role in triggering the political dispute. Consequently, Masatomo was prevented from entering Kamakura while Yoshikane lost his position so the formation of a Shiba army failed to materialize.
Thereafter, Uesugi Masanori (Mochitomo’s son) served as the new secretary of Kantō, endeavoring with Masanori to rebuild relationships with leaders in Kantō such as the Uesugi clan. In 1465, when Shigeuji’s forces attacked again, Masatomo dispatched Masanori to Ikakkojin to establish a front-line. Owing to the demotion of Yoshikane, Masatomo could not count on the Shiba clan to supply forces, so he strengthened ties with the local families of influence in eastern Suruga. In 1471, his forces combined with reinforcements from the Uesugi to crush Shigeuji’s army after an attack on the Horigoe gosho, proceeding to attack and capture Shigeuji’s main base at Koga Castle. However, in 1472, Shigeuji staged a comeback and the situation reverted. In 1476, the death in battle of Imagawa Yoshitada, the military governor of Suruga, triggered an internal struggle. Masatomo dispatched Masanori to Suruga to intervene together with Ōta Dōgan, head of affairs of the Ōgigayatsu family. As a result of the mediation, Oshika Norimitsu (a cousin of Yoshitada and grandchild of Masanori from a daughter married into another family) served in lieu of Ryūōmaru, the son of Yoshitada.
In the midst of these developments, Nagao Kageharu, a senior retainer of the Yamauchi-Uesugi family, launched a rebellion known as the Nagao Kageharu Conflict. While Ōta Dōgan sought to suppress the rebellion after returning from Suruga, Shigeuji allied with Kageharu and joined the battle. Facing dire circumstances, the Uesugi families began to consider a settlement, promising to serve as intermediaries between Shigeuji and the bakufu. After Masatomo settled with Shigeuji and suppressed the rebellion, Shigeuji and the bakufu reconciled early in 1463 and the Kyōtoku Conflict came to an end. Prior to reaching a settlement, Masatomo engaged in conflict against Shigeuji and the forces supporting the Koga kubō for over twenty years. This, however, occurred during the height of the Ōnin-Bunmei Conflict so the bakufu was unable to field adequate military forces needed to control the entire Kantō Region. As a final outcome, the Horigoe kubō stood to govern only the single province of Izu, while Masatomo remained dissatisfied with Masanori and the local families of influence in Izu who advocated for the settlement.
After the reconciliation, Masatomo sought to change the policies of the bakufu. In the spring of 1487, he dispatched his second son, Ashikaga Seikō (later known as Ashikaga Yoshizumi) to Kyōto for an in-person meeting with Yoshimasa. He removed his eldest son, Ashikaga Chachamaru, from the line of succession, and designated his third son of the same mother as Seikō, Ashikaga Jundōji, as his successor. Masatomo compelled Masanori to kill himself for having opposed the removal of Chachamaru from the line of succession. Through a series of events, he allied with Hosokawa Masamoto, the deputy shōgun, to devise a plan to overthrow Ashikaga Yoshiki (later known as Ashikaga Yoshitane), the tenth shōgun. Masatomo had a connection to Masamoto after Masamoto adopted Sōmeimaru, a cousin of Seikō’s mother. The plan called for Seikō to become the next shōgun and for Jundōji, in his role as Horigoe kubō, to re-launch a campaign to oust Shigeuji. However, early in 1491, Masatomo fell ill and, in the spring, he died in Izu.
Three months after the death of Masatomo, a succession struggle arose between Jundōji and Chachamaru to become the next Horigoe kubō. Chachamaru broke out of prison by killing his guard, and then proceeded to slay Jundōji and his mother, Enman-in, who had supported Jundōji. By this means, Chachamaru seized the position of the Horigoe kubō. Two years later, in 1493, Masamoto ousted Yoshiki in the Meiō Political Incident and backed Seikō as his replacement. After becoming the eleventh shōgun, Seikō changed his name to Yoshitane and ordered Ise Sōzui (later known as Hōjō Sōun) to invade Izu to eliminate Chachamaru. Chachamaru ulitmately lost to Sōzui and killed himself, bring an end to the Horigoe kubō after only two generations. The descendants of Yoshizumi served as shōgun in later generations.