Battle of Nagahama
Date: 5/28 of Eiroku 3 (1560)
Location: Tonomoto in the environs of Nagahama Castle in Tosa Province
Synopsis: In the early part of the Sengoku period, power and territory in Tosa Province were distributed among seven gōzoku, or wealthy families, competing among one another. In the eras of Chōsokabe Kanetsugu and his son, Chōsokabe Kunichika, the clan gradually consolidated power, leading to a final showdown against the Motoyama clan. In the Battle of Tonomoto, the Chōsokabe prevailed while the Motoyama lost numerous bases. Later, the remaining members of the Motoyama finally surrendered to Chōsokabe Motochika.
The Battle of Nagahama occurred on 5/28 of Eiroku 3 (1560) in Nagahama in Tosa Province. The conflict was waged between the Chōsokabe clan (sengoku daimyō) and the Motoyama clan who vied for influence in the province. The main battle at Tonomoto was the first experience in battle for Chōsokabe Motochika.
After the Ōnin-Bunmei War, the system of governance by the Hosokawa clan serving as military governors of Tosa was weakened, and a group of seven gōzoku, or wealthy families, referred to as the Tosa shichiyū gained prominence and competed for territory. These families included the Motoyama, the Kira, the Aki, the Tsuno, the Kōsokabe, the Ōhira, and the Chōsokabe. Among these clans, the Chōsokabe, who were powerful retainers of the Hosokawa family, expanded their power. At this time, Chōsokabe Fumikane received Ichijō Norifusa (who fled war in the Kinai) as the provincial governor. By forming a joint body of kokujin, or provincial landowners, with the Ichijō clan as the leaders, he brought stability to Tosa.
After experiencing a temporary period of decline, the Chōsokabe recovered their power and served as a patron of the Hosokawa. Having newly acquired the authority of the Ichijō clan, over the course of several generations, the Chōsokabe strengthened their influence. Chōsokabe Kanetsugu (the father of Chōsokabe Kunichika), expanded the authority and governance of the clan in their territory.
While Kanetsugu excelled in literature and the military arts, he gradually came to act in an arrogant manner. In 1507, Hosokawa Masamoto was assassinated in the Lord Hosokawa Incident, triggering a succession struggle that led to another period of instability known as the Eishō Disturbance. Meanwhile, dissatisfaction spread among the kokujin in Tosa, giving rise to an allied army led by the Motoyama, in addition to the Ōhira, the Kira, and the Yamada, opposed to the Chōsokabe. Kanetsugu headed-out to intercept them, but, in the end, he was cornered in his base at Okō Castle and took his own life. Kanetsugu’s eldest son, Kunichika, relied upon Ichijō Fusaie to flee, but his power receded while this incident determined the destiny of relations between the Chōsokabe and the Motoyama. The loss of influence of the Hosokawa led to a collapse of the governance of the Muromachi bakufu within the province while local clans in Tosa fought among themselves in the Sengoku period.
Under the protection of the Ichijō clan, in 1518, Kunichika was able to return to Okō Castle in his former territory. While Yoshida Takayori and other retainers served as his guardians, Kunichika endeavored to revive the Chōsokabe family, bringing in the Yamada, the Kōsokabe, and Kira clans to expand the power of the family. He sought to strengthen the army and enrich the province based on a system conceived by the Chōsokabe known as ichiryō-gusoku to organize and deploy personnel who split their time between military service and farming. Kunichika forged ties with Motoyama Shigemune of the powerful Motoyama clan in Tosa through a political marriage by having his daughter wed Shigemune’s eldest son, Motoyama Shigetoki. Around this time, among the seven wealthy families known as the Tosa shichiyū, the only clans remaining were the Chōsokabe, the Motoyama, and the Aki clans.
After the death of Shigemune in 1555, Kunichika increased pressure upon the Motoyama clan. As Shigemune’s successor, Shigetoki sought revenge by arranging for residents of Oe under his command to take by force in Urado Bay military provisions for the Chōsokabe that were being shipped by vessel to Tanezaki Castle. This incident raised tensions between the two clans.
Course of events
Kunichika made plans to invade the territory of the Motoyama, but Nagahama Castle on the front lines of their territory was a stronghold that could not easily be captured. Over the years, however, the castle gate had begun to decay so Shigetoki ordered a former retainer of Kunichika known as Fukudome Chikamasa (Uma-no-jō) who was skilled in castle construction to rebuild the gate. Upon hearing this news, Kunichika sent a messenger to Chikamasa, offering him landholdings if he returned to the service of the Chōsokabe and then plotted for Chikamasa to have the gate opened by those inside the castle grounds.
On 5/27 of Eiroku 3 (1560), Kunichika launched a nighttime attack from Tanezaki Castle to Nagahama Castle. Guided by Chikamasa, the Chōsokabe broke-through the castle gate whereupon the defenders inside vacated the castle with minimal resistance. The forces then massed at the main base of the Motoyama clan at Motoyama Castle.
On the morning of 5/28, the Chōsokabe army deployed south from Nagahama Castle to Sekkei Temple. Meanwhile, the Motoyama army established a position to the west in Hideno. From around 10:00 AM, the two armies engaged in a violent clash in the Battle of Tonomoto. Initially, the battle favored the Motoyama with their superior numbers, but, in the midst of a chaotic scene, the Chōsokabe pushed back against the Motoyama army and Shigetoki withdrew to Urado Castle. In their pursuit of the Motoyama forces, the Chōsokabe utilized vessels along the shoreline to the north and south, imposing a blockade of Urado Castle. The Chōsokabe also installed fences on land to surround the castle, but, owing to sudden illness by Kunichika, were forced to withdraw several days later.
The Battle of Tonomoto was the first experience in war for Kunichika’s eldest son, Chōsokabe Motochika, at the relatively late age of twenty-two. Teased as a princess child by those around him, he was frail and, prior to the deployment, received instruction in the handling of a spear from a retainer named Jinsenji Bungo. Nevertheless, once the fighting began, Motochika led a unit of fifty soldiers and captured seventy heads. Motochika himself killed two members of the enemy cavalry. Riding the momentum of victory, Motochika shook off the restraint of Kunichika and others to attack Oe Castle, an ancillary castle aligned with the Motoyama, and, after assessing it was undefended, charged in to capture the base. Thereafter, owing to his actions on the battlefield as though of a different person, Motochika was called the devil child and regarded with awe. On this occasion, his younger brother, Chōsokabe Chikasada, also participated in battle for the first time.
Despite their superior military power, as an outcome of this battle, the Motoyama lost numerous bases to the Chōsokabe, casting a dark shadow over the clan. Although the Chōsokabe prevailed in the final showdown, just before finishing off the Motoyama, Kunichika fell ill and was forced to retreat. Attempts to treat him at Okō Castle were to no avail, and he died soon thereafter. Kunichika noted to Motochika in his last will that expelling the Motoyama would be the best tribute he could give, showing regret for not doing so.
After succeeding Kunichika, Chōsokabe Motochika, conducted operations to undermine the Motoyama clan, and, in 1562, compelled the destruction of Asakura Castle where Shigetoki had holed-up, further weakening the clan. Shigetoki’s son, Motoyama Chikashige, later surrendered to the Chōsokabe.
Thereafter, Motochika aimed to liberate the Chōsokabe from the influence of the Ichijō clan. In 1569, he eliminated Aki Kunitora who had ties to Ichijō Kanesada and, in 1575, decimated the Ichijō clan at the Battle of Shimantogawa en route to unifying Tosa Province. Motochika then aimed to pacify all of the territory in Shikoku, making great strides in that direction until, in 1585, the Invasion of Shikoku by Hashiba Hideyoshi.