Siege of Kannonji Castle

観音寺城の戦い

Oda Clan

Ōmi Province

Rokkaku Clan

Date:  9/12 of Eiroku 11 (1568)

Location:  Primarily around Mitsukuri Castle in the south-central part of Ōmi Province

Outcome:  Rokkaku Yoshikata and his son, Yoshiharu, planned for a prolonged battle, spreading forces across many secondary castles in Ōmi, but after the fall of Mitsukuri and Wadayama castles in a single day, they fled from Kannonji Castle to continue their resistance, while Nobunaga marched to Kyōto and installed Ashikaga Yoshiaki as the fifteenth shōgun of the Muromachi bakufu.

Commanders:  Oda Nobunaga, Kinoshita Hideyoshi, Niwa Nagahide, Shibata Katsuie, Mori Yoshinari, Inaba Yoshimichi, Takigawa Kazumasa, Azai Nagamasa, Kanbe Tomomori, Matsudaira Nobukazu

Forces:  50,000 to 60,000

Casualties:  Over 1,500

Commanders:  Rokkaku Yoshikata, Rokkaku Yoshiharu, Rokkaku Yoshisada, Gamō Katahide, Yoshida Shigemasa, Tanaka Jibu-Taifu

Forces:  11,000

Casualties:  Unknown

The Siege of Kannonji Castle occurred on 9/12 of Eiroku 11 (1568).   While en route to Kyōto to install Ashikaga Yoshiaki as the next shōgun, Oda Nobunaga triggered this conflict against Rokkaku Yoshikata and Rokkaku Yoshiharu (father and son), the military governors of Ōmi Province.  The primary site of the battle was at Mitsukuri Castle so this conflict is also referred to as the Battle of Mitsukuri Castle.

This was the first battle to occur after Nobunaga proclaimed restoration of the Muromachi bakufu among the five provinces comprising the Kinai Region.  The battle had an impact on the ensuing pacification of Kyōto and the Kinai, providing an opportunity to use the title as de facto ruler of the country.  If the period after Nobunaga’s march upon Kyōto marked the beginning of the Azuchi-Momoyama period, then the Siege of Kannonji Castle was the final battle of the Sengoku period.  After the fall of Mitsukuri Castle in one night, the defenders vacated Kannonji Castle without bloodletting while the Rokkaku clan fled to the Kōka District.

Events leading to the outbreak of hostilities

On 5/19 of 1565, Ashikaga Yoshiteru, the thirteenth shōgun of the Muromachi bakufu, was killed by the Miyoshi Group of Three in the Eiroku Incident.  Yoshiteru’s younger brother, Ichijōin Kakukei (later known as Ashikaga Yoshiaki) was a priest at the Ichijō monastery in the Kōfuku Temple, but, with the assistance of Wada Koremasa, a bushi from Kōka,  he escaped from Nara.  Thereafter, he drifted for approximately three years.

First, Kakukei headed toward Wada Castle in the Kōga District of Ōmi, but then he set-up a temporary residence in the town of Yajima in the Yasu District of Ōmi which was closer to Kyōto.  For a while, he attempted to rely upon Rokkaku Yoshiharu for support, but, after learning that Yoshiharu was in communication with the Miyoshi Group of Three,  he then turned to Takeda Yoshimune of Wakasa Province and Asakura Yoshikage of Echizen Province.  While in Echizen, he dropped his priest’s name of Ichijō Kakukei and adopted the name of Ashikaga Yoshiaki.  After learning that Yoshikage would not take action, he then sought help from Oda Nobunaga through the offices of Akechi Mitsuhide.

In the eleventh month of 1567, Nobunaga received a private order from the chamberlain’s office of Emperor Ōgimachi to return the imperial lands in Owari and Mino that were not part of a fief.  After receiving the order, Nobunaga began his march toward Kyōto.  After Yoshiaki arrived from Echizen to meet Nobunaga at the Ryūshō Temple in Mino, on 8/5 of 1568, he departed from Gifu Castle and, accompanied by 250 mounted soldiers, arrived on 8/7 at Sawada Castle.

Kannonji Castle in Ōmi was on the route to Kyōto.  Nobunaga assigned three retainers to Wada Koresama, who was a trusted retainer of Yoshiaki and sent a messenger to Rokkaku Yoshiharu in Kannonji Castle requesting that he assist Yoshiaki’s entrance into the capital.  However, Yoshiharu and his father, Yoshikata, rejected this offer.  Just before Nobunaga’s arrival at the camp, the Miyoshi Group of Three and Shinohara Nagafusa headed toward Kannonji Castle and held a deliberation in regard to an invasion by the Oda army.  After the rejection by the Rokkaku, Nobunaga sent a messenger again, demanding support to enter the capital. There are various theories concerning the these calculations, such as a plan to have retainers reside in Kannonji Castle as was done later at Azuchi Castle, or to leverage the political structures of the Rokkaku to establish a free market, and, most likely, sought to avoid a final showdown against such a progressive clan serving as the military governors of Ōmi.  Meanwhile, Yoshiharu was likely focused on the military power of the Miyoshi Group of Three.  Citing illness, he sent the messenger back without a meeting.  After staying in Sawada Castle for seven days, Nobunaga concluded that hostilities were unavoidable, and, at once, returned home.

On 9/7 of 1568, Nobunaga readied a contingent of 15,000 soldiers and departed Gifu Castle.  In addition, Tokugawa Ieyasu of Mikawa sent 1,000 men while Azai Nagamasa of northern Ōmi sent 3,000 men.  On 9/8, the army arrived at Takamiya, and, on 9/11, marched to the northern shore of the Echi River.  By this time, the Oda army had swelled to 50,000 to 60,000 soldiers.  The Rokkaku responded by positioning, at their main base at Kannonji Castle, 1,000 mounted soldiers under Yoshikata, Yoshiharu, and Yoshiharu’s younger brother, Rokkaku Yoshisada, and, at Wadayama Castle, a main force of 6,000 soldiers under the command of Tanaka Jibu-Taifu, and, at Mitsukuri Castle, 3,000 soldiers headed by Yoshida Izumo-no-kami and others.  In addition, they disbursed the servants across eighteen secondary castles in support of Kannonji Castle.  The Rokkaku set-up their defenses in anticipation of the Oda first attacking Wadayama Castle.  From there, they likely planned to launch a pincer attack from Kannonji and Mitsukuri castles.

Battle situation

Nobunaga’s actions had a contrary effect.  In the early morning of 9/12, after the Oda army traversed the Echi River, the forces split into three divisions.  Inaba Yoshimichi led the first division toward Wadayama Castle, Shibata Katsuie and Mori Yoshinari led the second division toward Kannonji Castle, and Takigawa Kazumasu, Niwa Nagahide, and Kinoshita Hideyoshi led the third division toward Mitsukuri Castle.

The battle first broke out at Mitsukuri Castle.  Hideyoshi led 2,300 soldiers to attack the north entrance while Nagahide led 3,000 soldiers to attack the east entrance.  Mitsukuri Castle was on a steep hill blanketed with large trees, making it difficult to attack.  Meanwhile, Yoshida Izumo-no-kami led a stiff defense so that, around 5:00 PM, the attacking forces began to fall apart.  The division led by Hideyoshi held a deliberation and decided to launch a nighttime attack.  Hideyoshi had his men prepare several hundred torches approximately one meter in length, positioned troops at fifty locations around the middle of the mountain, and, all at once, lit the torches to serve as a signal for a mass assault.  The Oda forces caught the defenders off-guard, and, after over seven hours of fighting, the castle fell before dawn.  The attackers brought over 200 heads of the enemy soldiers.  After learning about the fall of Mitsukuri, the soldiers positioned at Wadayama Castle fled without fighting the Oda.

Having anticipated a long battle, Rokkaku Yoshiharu was disappointed to learn that, in less than one day from the outbreak of hostilities, both Mitsukuri and Wadayama had been lost.  Perhaps because he realized the defenses at Kannonji Castle were vulnerable, to avoid a precedent that would be cited for time immemorial, he fled at night to Kōga.  With the exception of one, the eighteen supporting castles lost their leaders and surrendered to the Oda army with the outcome largely decided.  In the course of this conflict, the Oda army lost as many as 1,500 soldiers.

The defensive strategy of the Rokkaku relied upon the interception of attacking forces from castles positioned along the front lines of the battle.  This conflict marked the first time that Kannonji Castle itself had been attacked in 70 years, since an attack by Saitō Myōjun in 1496.  From the perspective of a defensive strategy, Kannonji Castle had been functioning more as an administrative center for the military governor of Ōmi rather than as a base for combat.  To serve the Tōsandō administrative area, the castle featured a very open design making it difficult to defend in the event of an attack.  The Rokkaku did not likely anticipate that Nobunaga would head directly toward Kannonji Castle for an attack.

Consequences of the battle

After learning of the defeat, a key retainer of the Rokkaku named Gamō Katahide displayed an intent to continue the resistance by hunkering down along with 1,000 soldiers in Hino Castle whereupon Kanbe Tomomori, a commanding officer n the Oda family who was married to Katahide’s younger sister, paid a visit by himself to Hino Castle.  As a result of these discussions, Katahide surrendered, tendered his eldest son, Tsuruchiyo (later known as Gamō Ujisato), as a hostage, and became a retainer of the Oda, serving as a yoriki, or security staff, for Shibata Katsuie.  Nobunaga took favor with Katahide and Tsuruchiyo, having Tsuruchiyo marry his daughter, Sō-ō-in, so that Tsuruchiyo became Nobunaga’s son-in-law.  Later, after formation of the Encirclement Campaign against Nobunaga, Katahide was solicited by the Rokkaku to oppose Nobunaga, but he firmly rejected the offer, electing to fight as a commanding officer for the Oda.

Despite having lost Kannonji Castle, the Rokkaku continued to show an intent to reside the Oda army.  However, with their former territory under the control of the Oda, the most that could be achieved were small skirmishes.  The fall of the Rokkaku as sengoku daimyō of Ōmi Province was definitive.

The Miyoshi Group of Three and others in control of Kyōto at the time became anxious upon hearing that the Rokkaku had been defeated.  These forces were subsequently expelled from the capital without much of a fight.  Nobunaga sent a messenger to Ashikaga Yoshiaki at the Ryūshō Temple in Mino, informed him of the war situation and encouraged him to depart.  On 9/27 of 1568, Nobunaga and Yoshiaki went to the Mitsui Temple on Lake Biwa.  On 9/28, they entered Kyōto where Yoshiaki set-up at the Kiyomizu Temple and Nobunaga set-up at the Tōfuku Temple.  Hosokawa Fujitaka provided security for the Imperial Court.

In this way, Nobunaga garnered control of the Kinai, while Yoshiaki assumed the role as the supreme shōgun.