Ninth Campaign of Obi
Date: Eiroku 11 (1568)
Location: The environs of Obi in the southern portion of Hyūga Province
Synopsis: The Ninth Campaign of Obi marked the final battle in a longstanding conflict between the Shimazu-Hōshū and Hyūga-Itō clans for control of Obi Castle and its environs in southern Hyūga Province. Despite fielding a larger army, the Shimazu forces were gradually surrounded by the Itō army at Ogoe. Accompanying the collapse of their formations, the Shimazu fled toward Sakatani Castle with the Itō in pursuit. As evidence of their defeat, in a subsequent settlement, the Shimazu turned over Obi and Sakatani castles to the Itō clan.
Commanders: Shimazu Tadachika, Hongō Tokihisa, Tsuchimochi Yoritsuna
Forces: 13,000 (7,000 led by Shimazu Tadachika, 6,000 led by Tsuchimochi Yoritsuna)
Losses: Over 800 at the Battle of Ogoe
The Ninth Campaign of Obi occurred in 1568 in the southern portion of Hyūga Province in Kyūshū. The conflict was waged between Itō Yoshisuke (the eleventh head of the Hyūga-Itō clan) and Shimazu Tadachika (the fifth head of the Shimazu-Hōshū clan), allied with Hongō Tokihisa. The Shimazu-Hōshū were a cadet family of the main branch of the Shimazu family, having moved from Chōsa in Satsuma Province to Obi in southern Hyūga Province in the era of Shimazu Tadakado (the second head of the Shimazu-Hōshū) around 1486. Based in northern Hyūga, the Hyūga-Itō challenged this encroachment by the Shimazu-Hōshū into Hyūga. The Ninth Campaign of Obi marked the final battle in a conflict between the Hyūga-Itō and the Shimazu-Hōshū clans that ran over an eighty-year period for control of Obi Castle and its environs.
In 1484, the Itō clan who governed the north-central portion of Hyūga joined forces with Shimazu Hisayasu to deploy to Obi. Hisayasu, who was from Kushima in the southernmost portion of Hyūga, was in conflict with a retainer of the Shimazu named Niiro Tadatsugu of Obi. In 1485, an army of 16,000 men laid siege to Obi Castle. At the height of this siege, however, Itō Suketaka died in battle. Thereafter, his son, Itō Sukekuni, was killed fighting against Shimazu forces who came to the aid of the defenders at Obi Castle. As a result, the Itō army was forced to withdraw while their bid to capture the castle failed. This is known as the first and second campaigns of Obi.
In 1536, after Itō Yoshisuke became the head of the Itō family, Shimazu Tadahiro of the Shimazu-Hōshū family backed a rebellion by Nagakura Sukeyoshi against the Itō clan. This event, in addition to lingering enmity owing to the death of Sukekuni, resulted in violent clashes with the Hōshū family in control of Obi. On many occasions, the Itō sought to capture Obi Castle, and, in 1562, despite success in its capture, it was recaptured by the Shimazu just six months later as the struggle for control persisted. This is known as the third to eighth campaigns of Obi.
On 1/9 of Eiroku 11 (1568), in the Ninth Campaign of Obi, Yoshisuke led a contingent of 20,000 troops to Sadowara Castle with the aim of capturing Obi Castle. On 1/11, he had forces amass at Oniga Castle and, on 1/13, arrived at Sasagamine. With Itō Sukemoto serving as the commander-in-chief, Yoshisuke assigned 3,800 troops to Itō Sukemune to establish a position at Niiyama, 11,000 troops to Ochiai Kaneoki and Kiwaki Sukemori to the south of Ogoe, and 3,200 troops to Nagakura Sukenami and Kawasaki Chikara-no-suke at Ranketsu-ka-o. He further positioned a detached division of 2,600 troops at Futohara-Takamine and Shinyama-Kobyō to surround Obi Castle. According to one account, he positioned the remaining 400 troops as guards on Sasagamine.
Meanwhile, Hongō Tokihisa (allied with the Shimazu) led an army of 6,000 soldiers to serve as a rear guard entered Sakatani Castle – an outlying castle located to the west of Obi Castle.
Course of events
On 1/21, the Itō army incurred an attack by the Shimazu army, but proceeded to surround Obi Castle and carry out a continuous assault. Within Obi Castle, the military provisions were already dwindling so Kashiwabara Hitachi-no-kami (the lord of Sakatani Castle) held a council with Hongō Zusho-no-suke and decided to send reinforcements to Obi Castle. Early in the morning on 2/21, a total of 13,000 troops amassed at the Ata Pass, including a Hongō army of 6,000 troops under the command of Tsuchimochi Yoritsuna and a Shimazu army of 7,000 troops under Shimazu Tadachika. Additional Shimazu forces from Obi Castle deployed to Ōsakoguchi to meet them.
Meanwhile, the Shimazu forces confirmed the arrival of the Itō army in Takeno to the west of Ogoe. First, after Ochiai Kaneoki and Kiwaki Sukemori headed toward Ogoe, Itō Sukeyasu and Itō Sukekiyo followed them and, upon the sound of arquebus fire as a signal, launched an all-out assault against the Shimazu army. Despite efforts to fight back, the Shimazu forces gradually became surrounded by the Itō army around Ogoe. After Itō Sukeyasu and Kiwaki Sukemori drew the enemy forces close by and initiated attacks to disturb the formations of the Shimazu army, Ochiai Kaneoki, Kawasaki Chikara-no-suke, and Yamada Munemasa captured heads one after another, while the state of the battle leaned in favor of the Itō. Further, after Nagakura 伴八郎 and other members of the Itō army charged from the flanks, the Shimazu army quickly unraveled and its troops began to flee toward Sakatani in defeat. As the Itō army pursued them, the Shimazu continued to incur losses. After approaching near Sakatani Castle, the Itō forces yielded the attacks and withdrew.
In this battle, the Hongō and Shimazu armies suffered a major defeat by the Itō army, losing over 800 soldiers and commanders including Tsuchimochi Yoritsuna, Hongō Tadatoshi, Honda Chikatoyo, and Kashiwabara Hitachi-no-kami and 65 lords of castles. Amidst this defeat, the defenders abandoned hope for the arrival of reinforcements to Obi. After the Battle of Ogoe, Obi Castle itself had not yet fallen so the Itō army set-up a position at 細砂礫, severing the route to Shōnai and completely isolating Obi Castle. In the fifth month, the Itō army surrounded Sakatani Castle where Hongō Tokihisa was holed up. As a result, the Hongō army could not send troops again in support of Obi Castle. Facing a dire shortage of provisions, the defenders at Obi Castle confronted the prospect of cannibalization as the only means to survive. Moreover, Shimazu Tadachika was ill in bed so it became impossible to hold-out any longer.
Shimazu Michihisa came in support of Sakatani Castle, but, after learning of the major defeat of the Shimazu army at the Battle of Ogoe, Shimazu Takahisa of the main branch of the Shimazu clan made a decision to settle with Yoshisuke. In the middle of the fifth month, he dispatched Hongō Nakatoku who then entered into a settlement with the representative of the Itō, Mera Shigekata. Based on this agreement, on 6/6, Obi and Sakatani castles were turned over to the Itō while Shimazu Tadachika and members of the Shimazu-Hōshū family withdrew from southern Hyūga. The terms provided that the areas of Obi and Nangō are the territory of the Itō clan and the area of Kushima is the territory of the Kimotsuki clan. By this means, a conflict over Obi Castle between the Itō and Shimazu clans persisting for approximately 80 years finally came to an end. After completely removing the Shimazu-Hōshū family from southern Hyūga, Yoshisuke placed his son, Itō Suketake, in Obi Castle to solidify his governance, and, with the exception of the Kushima area, asserted control over almost all of the Naka and Miyazaki districts of Hyūga.
The victory in this battle gave rise to the period of peak prosperity for the Itō clan during which the clan cultivated friendly relations with powers in Hyūga, Satsuma, Ōsumi, and Higo provinces. The clan established a network of 48 castles and fortresses in their territory known as the Forty-Eight Castles of the Itō. In 1572, however, after the Battle of Kizakibaru, the influence of the Itō clan began to wane while the Shimazu clan unified their control of Satsuma and Ōsumi provinces followed by an invasion of the home province of the Itō in Hyūga. Once again, after a period of ten years, Obi Castle fell to the Shimazu. In 1587, owing to the Kyūshū Pacification by Toyotomi Hideyoshi in addition to resistance by bands of retainers of the Itō including Yamada Munemasa, the Shimazu were expelled from Hyūga. The castle was governed by the Shimazu until the return of Yoshisuke’s third son, Itō Suketake, as its lord based on contributions he made serving as a guide for the Toyotomi army during the Pacification of Kyūshū.