Invasion of Chūnō
Date: Eiroku 8 (1565) to Eiroku 9 (1566)
Location: The central portion of Mino Province
Synopsis: Following the death of Saitō Yoshitatsu in 1561, his illegitimate son, Saitō Tatsuoki, succeeded him, but owing to youth and inexperience, Tatsuoki made the clan vulnerable to attack from Oda Nobunaga based in the neighboring province of Owari. To exploit this opportunity, Nobunaga began an invasion of the central portion of Mino Province. With the support of Kajita forces from Mino, the Oda succeeded in subduing the Saitō and driving Tatsuoki out of the province.
The Invasion of Chūnō occurred from Eiroku 8 (1565) to Eiroku 9 (1566) and was waged between the Oda army and the Saitō army for control of the central portion of Mino Province.
Occupation of Inabayama Castle
Takenaka Shigeharu and Andō Morinari (Shigeharu’s father-in-law) were retainers of the Saitō family. After the death of Saitō Yoshitatsu on 5/11 of Eiroku 4 (1561), Shigeharu and Morinari served Yoshitatsu’s son and heir, Saitō Tatsuoki, who became the head of the family at the age of fourteen. Tatsuoki’s youth and inexperience shook the band of retainers so that, at once, the Saitō struggled to defend against invasions of Mino by Oda Nobunaga of neighboring Owari Province. In addition to his immaturity, Tatsuoki indulged in a decadent lifestyle and did not pay attention to affairs of governance. Furthermore, he took care of only some of his close retainers while distancing Shigeharu and the Western Mino Group of Three (Andō Morinari, Inaba Yoshimichi, and Ujiie Naomoto – influential retainers of the Saitō who later served the Oda) from governance of the clan.
At midday on 2/6 of Eiroku 7 (1564), Shigeharu joined his father-in-law, Morinari, to attack Tatsuoki at Inabayama Castle (later known as Gifu Castle), killing six people including Saitō Hida-no-kami, causing Tatsuoki to flee. The occupation of Inabayama Castle continued until around 7/29, and, in the eighth month, Tatsuoki appeared to have taken back the castle by force. There is also a theory that Tatsuoki was reprimanded and the castle returned, but given that the conflict persisted for nearly six months, a more likely explanation is that the occupiers abandoned the castle in response to attacks by supporters of Tatsuoki. After abandoning the castle, Shigeharu became reclusive. During the period of occupation, Nobunaga is said to have solicited Shigeharu to transfer the castle to the Oda, but Shigeharu refused. Nevertheless, the event made clear the deterioration of the Saitō clan, leading to conspicuous departures by retainers. Meanwhile, Nobunaga shifted his strategy from attacks on western Mino to attacks on the central portions of the province.
Course of events
The Satō clan were a powerful kokujin family based at Kajita Castle in a strategic location in Mino connecting Hida Province and eastern Mino. Satō Tadayoshi and Satō Tadayasu (father and son), together with the Kajita army (comprised of residents and bushō from the village of Kajita), responded to appeals from Umemura Ryōtaku, and through the collusive efforts of Niwa Nagahide, switched sides to the Oda. The collusion by the Kajita group provided a foundation for the unification of Owari and attacks in Mino, weakening the position of the Saitō.
In 1565, Nobunaga commenced attacks against Oda Nobukiyo, the lord of Inuyama Castle allied with the Saitō. After moving his base from Kiyosu Castle to Komaki Castle, Nobunaga continued governing Owari while attacking the central portion of Mino to weaken the grip of Saitō Tatsuoki. In Mino, Mori Yoshinari first attacked Torimine Castle, later changing the name to Kaneyama Castle.
The Oda army occupied Igiyama Castle and pinned down the Saitō. Nobunaga delegated the assault on Unuma Castle on the front lines of the battle in Mino to Kinoshita Hideyoshi, who, at the time, was an up-and-coming retainer. Ōsawa Jirōzaemon, the lord of Unuma Castle, put-up limited resistance, but was persuaded by Hideyoshi to open the castle.
Nobunaga advanced forces to Inuyama and Kurusu, and proceeded to attack Sarubami Castle defended by Tajimi Nobusato. In the course of the battle, the garrison imposed losses on the Oda army, but no allied reinforcement came in support. After Niwa Nagahide severed the water supply to the castle, Nobusato determined he could no longer resist and, together with his family, departed. Nobunaga recognized the contributions of Kawajiri Hidetaka who served in the vanguard for Nagahide and thereafter appointed him to serve as the next lord of the castle. To celebrate the victory, the castle was renamed Katsuyama Castle.
Three-way alliance among castles in Chūnō
Nagai Michitoshi (the lord of Seki Castle) devised a plan to ally with Kishi Nobuchika (the lord of Dōhora Castle) and Satō Tadayoshi (the lord of Kajita Castle) forging a three-way alliance. At this time, Tadayoshi’s daughter (Yaeryoku) was sent as a hostage for adoption by Nobuchika. This alliance enabled them to halt attacks by the Oda army in the central portion of Mino while the main division under Saitō Tatsuoki rushed in to sweep-up the Oda forces, going as far as to plan an invasion of Owari.
Attempt to lure Kishi Nobuchika
Nobunaga’s troops marched north toward Dōhora Castle, aiming to ally with Kishi Nobuchika who was known as an intrepid warrior and tactician for the Saitō clan. Kanamori Nagachika was dispatched as a messenger to persuade him to join the Oda, but the Kishi family refused, choosing instead to remain loyal to the three-party alliance and the Saitō clan. Right in front of the messenger, the eldest son of Kishi Nobufusa was beheaded, whereupon Nagachika said to the Kishi that they will meet in battle tomorrow and left the castle. Nobunaga recognized the reputation of the Kishi family as fierce warriors, and sought to ally with them and have them serve as leaders in the Oda family, but was compelled to give-up this wish and planned to attack Dōhora Castle located just several kilometers to the south of Kajita Castle.
Battle of Kajita and Dōhora Castles
At the stronghold of Dōhora, Nagai Michitoshi and Kishi Nobuchika devised a plan to lure Nobunaga’s army to the castle and, with the Kajita forces led by Satō Tadayoshi, the Seki army led by Michitoshi, and reinforcements from the main division of Saitō Tatsuoki, destroy the Oda in battle at Kajita and Dōhora. The soldiers led by Nobunaga marched north, laying siege to Dōhora Castle defended by Nobuchika. Satō Tadayoshi and the Kajita forces, however, colluded with the Oda army. Upon learning of the betrayal, the Kishi skewered Tadayoshi’s daughter, Yaeryoku, who served as a hostage and exposed her on a cross on Mount Nagaomaru facing Kajita Castle. That night, a veteran of the Kajita army named Nishimura Jirōbei recovered Yaeryoku’s body under cover of darkness and buried her remains at the Ryūfuku Temple.
Nagai Michitoshi of Seki Castle and Kishi Nobuchika of Dōhora Castle then surrounded Kajita Castle. After the arrival of the main division led by Saitō Tatsuoki, the besieging forces made plans to occupy the stronghold. Nobunaga received communications from the Kajita forces, whereupon, with Nobunaga as the commander-in-chief, a contingent quickly departed to intervene in the siege of Dōhora Castle. After the Kajita forces (who were members of the Fujiwara family allied with the Oda) betrayed the Saitō in favor of the Oda, the Kishi fought valiantly as an isolated army. Owing to the actions of the Oda army, the Seki army led by Michitoshi did not arrive at Dōhora Castle. The main force under Tatsuoki planned to join later. Outnumbered, the defenders in the castle put forth their utmost effort, but, after Kishi Nobuchika repelled enemy forces eighteen times, he pulled back to the inner citadel and took his own life. Dōhora Castle was burned and, after falling to the attacking forces, was abandoned. Later, it was used as a base by Mori Nagayoshi in the Battle of Kajita and Kaneyama.
Battle of Seki and Kajita Castles
Under the pretext of supporting Saitō Toshiharu (the youngest son of Saitō Dōsan), the Oda army led by Nobunaga attacked Dōhora Castle, after which Nobunaga spent one night at the residence of Satō Tadayoshi, the lord of Kajita Castle. The next day, Nobunaga conducted an inspection of heads taken from the Kishi family and returned to Inuyama. While en route, an army of Seki forces led by Nagai Michitoshi and a main division led by Saitō Tatsuoki of over 3,000 troops charged the Oda army. Nobunaga’s army had less than 700 soldiers, and, owing to the actions of the Kishi army, the Oda were unable to mount a serious defense, sustaining dead and injured forces. The Oda army retreated to open fields and confronted Tatsuoki. After feigning an offensive, the wounded soldiers fled and, in the end, the remainder of the force quickly withdrew. Following the abrupt retreat of the Oda forces, the main division of the Saitō army under Tatsuoki returned to Gifu Castle.
Later, forces commanded by Nagai Michitoshi and Hida Tadamasa (the lord of Yoneda Castle), together with reinforcements from Tatsuoki, made preparations for an assault on Kajita Castle. During a siege of Kajita Castle at the Battle of Seki and Kajita in the eighth and ninth months of 1565, the massive Seki army led by Michitoshi converged with reinforcements from the Saitō army to attack Kajita Castle from the west. Owing to the efforts of Saitō Toshiharu as the commander-in-chief of Oda reinforcements and Yuasa Sanuki leading the Kajita forces, the Seki army (Saitō forces) broke down during the assault and retreated in defeat. Meanwhile, Hida Tadamasa attacked from the east, but, after the retreat of the Seki army, Satō Tadayoshi took control in a violent battle on the Kawaura River that served as a natural moat to the castle, and succeeded in repelling the Hida forces. Upon the demand of Yoshiharu, the Kajita and Oda armies promptly attacked Seki Castle from the east, west, and south. In the subsequent siege of Seki Castle, Nagai Michitoshi managed to defend the site through a combination of ambushes and deceptive tactics, but, at last, reinforcements from Tatsuoki failed to arrive, whereupon Seki Castle fell and the central portion of Mino came under the control of Nobunaga. Thereafter, the Western Mino Group of Three colluded with the Oda army affiliated with Toshiharu.
The Kishi family was decimated at Dōhora Castle, but Kishi Nobukiyo (the son of Kishi Nobuchika) and Eihime (the daughter of Kishi Nobufusa) survived. Kishi Shinemon (the son of Kishi Nobusada) served Mori Yoshinari.
Owing to the invasion by the Oda army of the central portion of Mino, the Saitō clan lost communications with eastern Mino, rendering without meaning their alliance with the Takeda clan. Consequently, the Saitō clan wielded power only in western Mino. The clan also witnessed defections in western Mino, and the landholdings of the Western Mino Group of Three were recognized and became retainers of Saitō Toshiharu.
After the battles in the central portion of Mino, Hida Tadamsa, the lord of Yoneda Castle, surrendered to Nobunaga and, after obtaining recognition to his rights to his landholdings, became a yoriki, or security officer, in Toshiharu’s band of retainers.
Nagai Michitoshi lost governing authority over central Mino and, together with Saitō Tatsuoki, was ousted from Mino.
Saitō Tatsuoki was betrayed by his retainers through collusion with the Kajita group, suffering a loss of power. Following an attack on Gifu Castle by the Oda army, he was expelled from Mino.
Saitō Toshiharu, the younger brother of Nōhime (Nobunaga’s formal wife) was formally recognized as the heir to the Mino-Saitō clan. His older brother, Saitō Yoshitaka, was assigned by Toshiharu to serve as the chamberlain of Kajita Castle and, later, he served Nobunaga and Nobutada.
The Mino-Satō clan became relatives of Toshiharu. After marrying Seishitsuin as his formal wife, Toshiharu was adopted by her father, Satō Tadayoshi. Toshiharu became the second-generation lord of Kajita Castle in a strategic location for travel between Mino and Hida provinces while the Kajita forces served as the elite force among his retainers.