Battle of Usonobaru
The Battle of Usonobaru occurred over a period of approximately three months from the middle of the fifth month until 8/16 of Eiroku 2 (1559). This was the final showdown of an internal conflict in the territory of the Sagara clan based in the southern portion of Higo Province. Originating from differences over personal matters, the conflict escalated into the greatest battle in the Kuma District of Higo during the Sengoku period. The battlefield was set on the northern shore of the Kuma River in the environs of Taragi.
Trigger for hostilities
In 1559, three individuals working at Hitoyoshi Castle in Higo, namely, Kodama Yatarō, Hayata Heihachirō, and Fukami Shinzaemon, engaged in illicit sexual relations with numerous handmaids who served the mother of Marume Yoriyoshi (a magistrate for the Sagara clan). Their attempt to take away these women from their masters served as the trigger for hostilities.
After consulting with 智勝, a priest at the Sōkei Temple, they executed a plan to have Yoriyoshi quarrel with another magistrate named Higashi Nagatoshi (a peer and potential rival of Yoriyoshi), thereby creating an opportunity to take the maids out of the castle (or by killing Yoriyoshi and taking his servants). First, Kodama Yatarō went at night to the residence of Nagatoshi and told him a lie that Yoriyoshi intended to oust him in a bid to strengthen his authority. At first, Nagatoshi did not believe him but then Yatarō falsely asserted that Yoriyoshi secretly went to the castle each night to discuss the plot with his mother. Nagatoshi sent his nephew to investigate and learned that Yoriyoshi did in fact make nighttime visits to the castle. This led Nagatoshi to believe the story. Next, Hayata Heihachirō and Fukami Shinzaemon went to the residence of Yoriyoshi and told him that Nagatoshi was preparing to oust him, deepening the divide between the two.
Owing to her concerns of the situation, Naijō, the mother of Sagara Yoshihi (a sengoku daimyō and the eighteenth head of the clan), requested mediation by Higashi Naomasa, the lord of Yunomae Castle who was a relative of Yoriyoshi through marriage as well as a cousin of Nagatoshi. Naomasa visited the castle with the expectation that he would be ordered to kill one of them as a means to prevent a conflict. Given that he did not receive such an order, he obeyed Naijō by only informing Yoriyoshi that in the event of an emergency to flee to Yunomae Castle and then he returned home. After learning of these developments, Nagatoshi became alarmed that if Yoriyoshi and Naomasa supported Naijō to start a conflict, he would be labeled as a traitor.
Therefore, Nagatoshi decided to act first. Refusing to oppose his lord, he persuaded Yoshihi and Naijō of a plan. On the evening of 5/15 (or 5/19), he had them feign illness and secretly took them to Ikeji Castle. Around the time that Yoshihi and Naijō, accompanied by Nagatoshi, arrived at the castle, sixty retainers under Nagatoshi yelled “Eliminate Marume the traitor.” This contingent then went from Nagatoshi’s residence to set fire to Yoriyoshi’s residence. Shuddering in fear of a sudden attack, Yoriyoshi was left with no option other than to take his wife, children, and mother and flee for safety to Yunomae Castle. Contrary to his earlier promise, Naomasa was reluctant not to follow Naijō but joined those taking cover in the castle.
Course of events
Given that Yoriyoshi and the others had hurriedly sought refuge, there were insufficient provisions in the castle. This compelled Naomasa to dispatch laborers to bring-in rice from his own storehouses located in the township of Kamimura. He sent forces led by his younger brother, Tsunematsu Kurōdo, to protect them. After hearing this news, Yoshihi had Indō Yoriyasu lead forces on a deployment. Yoriyasu intercepted the contingent at Okunoichido-bashi, but his army was demolished and Yoriyasu himself sustained injuries and returned home.
Thereafter, those at Yunomae Castle received a report that soldiers from Hitoyoshi Castle planned to enter Taragi Castle from which to prepare for an attack against Yunomae Castle. In an effort to capture Taragi Castle before this occurred, on the evening of 8/15, Naomasa sent forces under Kurōdo to assault Taragi Castle. The nephew of the chamberlain of Taragi Castle (Iwasaki Kaga-no-kami) was in Yunomae Castle. Out of fear that his uncle would be killed, he made a plan by which to send his own handmaid outside of the castle and have her inform the defenders of the deployment. As a result, Kaga-no-kami had soldiers from Sue, Fukada, and Kigami lay in ambush. Once Kurōdo and his forces arrived, the soldiers who lay in wait launched a surprise attack but, instead, were crushed and the survivors fled in defeat to Taragi Castle. Kurōdo then led his troops on an attack against Taragi Castle, but, after failing to capture their target, withdrew to Usonobaru-Tendō-ga-o and set-up a base.
The next day, in addition to forces led by Naomasa, Yoriyoshi, and Kurōdo, reinforcements led by Nasu Takeharu of Kozaki Castle, Nasu Taketsuna of Mukaiyama Castle, and Nasu Takemune of Ōkawa Castle all from the village of Shiiba in the Higashi-Usuki District of Hyūga Province, set-up a formation at Usonobaru. In response, the Hitoyoshi group led by Indō Yoriyasu took a position in front of a monument to Emperor Yokose in Kurohiji in Taragi, while the Taragi group led by Fukami Sōzaemon, along with soldiers from Nasu, Fukada, and Kigami, landed at Hashi-Shikakura.
First, the Taragi group served in the vanguard, clashing with Naomasa and his forces. Sōzaemon and others were killed in action and the group from Taragi destroyed. Next, the Hitoyoshi group entered the battle, but the soldiers fighting on behalf of Yoriyoshi and Yoriyasu knew one another. Moreover, some were cousins or even brothers. Perhaps owing to their hesitation to fight one another, there was no significant change in the course of the battle, although the two sides engaged in spear fighting for as long as one hour. While enduring their second round of battle, Kurōdo’s forces began to show signs of fatigue while the group from Hitoyoshi pushed further ahead. Amidst the mayhem, Naomasa’s army was decimated. Yoriyoshi fled to Hyūga but Naomasa, in addition to Kurōdo and over 180 soldiers, died in battle. Meanwhile, the group from Hitoyoshi lost 62 members.
After learning of the defeat, Nakayama Izumi-no-kami, the chamberlain of Yunomae Castle, set fire to the castle and took his own life. The wife and children of Naomasa, along with Yoriyoshi’s mother and handmaids took their lives at Saikōjidani where they had fled. At this time, the handmaids (or servants) who had been a root cause for the conflict were all martyred.
In a copy of the Diaries of Yatsushiro, there is only one entry on the day of this battle, in reference to Taragi. It is not known whether there was further description in the original work. It does, however, state that Naomasa and Kurōdo died, and the castle was toppled, on 9/3 (instead of 8/16).
This conflict involved fighting by and among retainers and family members but was suppressed by groups from Hitoyoshi while many from Taragi died. As a result, the outcome is generally viewed as having increased the authority of Sagara Yoshihi. In particular, Yoshihi recognized the contributions of Kubota Echigo-no-kami who served as the lord of the manor of Kigami, increasing his fief and awarding him Mount Ōhira. Meanwhile, Higashi Noto-no-kami entered Yunomae Castle.
The three individuals responsible for triggering the conflict, namely, Kodama Yatarō, Hayata Heihachirō, and Fukami Shinzaemon, went into hiding during the battle. In 1560, they were apprehended and paraded around below the castle. Then, together with 智勝, the priest with whom they had consulted in regard to the plot, were all taken to Nakagawahara and beheaded, whilst their heads were left outside exposed to the elements. The Sōkei Temple had its origins in the Heian period and a lineage of thirteen abbots, but owing to its role in the conflict, the temple lost its abbot and soon fell into decline. At present, only a temple hall with a Kshitigarbha (Jizo) image remains.
After fleeing to Hyūga, Marume Yoriyoshi served Itō Yoshisuke. In 1572, at the Battle of Kizakibaru between the Itō and Shimazu clans, he was killed in action.