Second Siege of Sogō Castle
Date: 6/11 of Tenshō 12 (1584)
Location: The environs of Sogō Castle in Sanuki Province
Synopsis: After luring away the Sangawa and Yusa clans, Chōsokabe Motochika toppled Sogō Castle while Sogō Masuyasu fled.
The Second Siege of Sogō Castle occurred on 6/11 of Tenshō 12 (1584). This battle was waged between the army of Chōsokabe Motochika and the army of Sogō Masayasu.
In the fourth month of 1583, upon orders of Hashiba Hideyoshi, Sengoku Hidehisa went from Awaji Island to Shōdo Island and attacked Kioka and Yashima castles. These efforts failed and his forces withdrew. An army commanded by Konishi Yukinaga sailed to the Kōzai Inlet, but, in the face of a counterattack by the Chōsokabe army, could not make a landing and was forced to retreat.
At the same time, the main division commanded by Motochika proceeded from Awa Province, crossed Ōkubo, set-up a base on Mount Tamo, and engaged in attacks on Toramaru Castle in Sanuki Province. Clashes occurred in the environs of Yoda and Irino, but, owing to counterattacks by forces led by Sogō Masayasu, the Chōsokabe army shifted their strategy to a war of attrition by cutting down wheat crops and plowing-under the rice seedlings, thereby depriving the defenders of their food provisions.
Based on information that the army of Sengoku Hidehisa had entered Hiketa Castle, Motochika dispatched the battalion led by Kagawa Yukikage, leading to the Battle of Hiketa. After suffering a defeat, the Sengoku army retreated by boats to Awaji Province. Masayasu withdrew from Toramaru Castle and entered Sogō Castle. According to one theory, Toramaru Castle was toppled in the seventh month of the following year, but the details are uncertain.
Meanwhile, at the Battle of Komaki-Nagakute, Hideyoshi continued fighting against the allied forces of Oda Nobukatsu and Tokugawa Ieyasu. At this time, Ieyasu allied with Motochika and called upon him to advance to Awaji. Hideyoshi quickly responded to these developments by returning to Ōsaka Castle to reinforce his defenses. Hearing of the return of Hideyoshi to Ōsaka, Ieyasu urged Motochika to immediately go forward, however, given concerns with respect to the actions by the dogō, or small-scale landowners, in Iyo Province and invasion by the Mōri clan, and because Sogō Castle had not fallen, Motochika was not in a position to act upon Ieyasu’s request.
Seeking to quickly pacify Shikoku, Motochika succeeded in luring away the Sangawa and Yusa clans from the Sogō army and join his side. By leveraging these clans, he captured Ametaki Castle, followed by other outlying castles ancillary to Sogō Castle. On 6/11 of Tenshō 12 (1584), Motochika finally toppled Sogō Castle and the Second Siege of Sogō Castle came to an end. However, on the prior evening of 6/10, Masayasu fled the castle. Masayasu and Masayuki offered to surrender to Motochika, but then traveled from Yashima to Bizen Province and on to Sakai, thereafter coming under the command of Hashiba Hideyoshi.
When Oda Nobukatsu, an ally of the Chōsokabe army, learned that Sogō Castle had fallen, in a letter dated 8/19 and addressed to Kōsokabe Chikayasu (Motochika’s younger brother), he expressed his delight that, based on a letter that he received, the impregnable fortress of Sogō had been taken in an assault on 6/11.
Sogō Castle was attacked by the Chōsokabe army and a retainer of the Chōsokabe named Hewa Chikatake became the lord of the castle, but, after the Hashiba army invaded Sanuki, in 1585, the Chōsokabe withdrew and Hidehisa became the most powerful figure in Sanuki. Sogō Masayuki was granted a fief of 20,000 koku and his rights to Sogō Castle were restored. In 1586, however, after joining the Conquest of Kyūshū, he was killed in action against the Shimazu clan at the Battle of Hetsugigawa in Bungo Province. Thereafter, Sogō Castle was abandoned.