Battle of Mimikawa

耳川の戦い

Shimazu Clan

Hyūga Province

Ōtomo Clan

Date:  Tenshō 6 (1578)

Location:  Takagigawahara in Hyūga Province

Synopsis:  In this era, the Shimazu of Satsuma Province in the south and the Ōtomo of Bungo Province in the north were the two most powerful clans in Kyūshū.  Despite a history of friendly relations, tensions arose as the Ōtomo advanced further south while the Shimazu marched north.  The two armies clashed in Hyūga Province with the Shimazu prevailing as the Ōtomo attempted to flee north toward their home province of Bungo.

Lord:  Shimazu Yoshihisa 

Commanders:  Shimazu Yoshihiro, Shimazu Iehisa, Shimazu Mochihisa

Forces:  20,000 to 30,000

Losses:  Unknown

Lord:  Ōtomo Sōrin  

Commanders:  Tawara Chikakata, Takita Shigekane, Saeki Sōten

Forces:  30,000 to 40,000

Losses:  Unknown

The Battle of Mimikawa occurred in Tenshō 6 (1578) at Takagigawahara (the fields along the Takagi River) in Hyūga Province.  The conflict was waged between Ōtomo Sōrin (a sengoku daimyō and twenty-first head of the Ōtomo clan) of Bungo Province and Shimazu Yoshihisa (a sengoku daimyō and the sixteenth head of the Shimazu clan) of Satsuma Province.

Relationship between the Ōtomo and the Shimazu prior to the Tenshō era (1573 to 1593)

The Ōtomo clan of Bungo and the Shimazu of Satsuma maintained friendly relations over a long-period of time.  With respect to conflicts between the Shimazu and the Itō of Hyūga Province, since the Eishō era (1504 to 1521), the Ōtomo frequently served as a mediator on terms favorable to the Shimazu.  The two clans were de facto allies who refrained from interfering in the spheres of influence of one another.  In the midst of continuing instability in the territory of the Shimazu, the relationship with the Ōtomo was important to the security of their own province.  Meanwhile, owing to a desire to further trade with the Ming dynasty in China, the relationship with the Shimazu was valued by the Ōtomo as a means to protect their seafaring vessels.  In a letter dated 8/25 of Tenshō 1 (1573) from senior members of the Ōtomo (Tawara Chikakata, Usuki Akisumi, Shiga Chikanori, and Saeki Korenori) addressed to the council of elders of the Shimazu (Kawakami Tadakatsu, Shimazu Suehisa, Murata Tsunesada, Ijūin Hisanobu, Hirata Masamune, and Ijūin Tadamune) regarding the handling of Ōtomo vessels that drifted ashore in the territory of the Shimazu, the Ōtomo noted the good relations betwene the clans for generations and, in their reply to the Ōtomo, the Shimazu noted the strong bonds between the families, evidencing their alliance.  In 1560, when Ashikaga Yoshiteru (the thirteenth shōgun of the Muromachi bakufu) mediated in a conflict between the Shimazu and Itō clans, Shimazu Takahisa noted in a letter to a retainer named Kabayama Yoshihisa that he told a messenger of Yoshiteru named Ise Sadataka (the steward of the mandokoro, or official in charge of the administration of domains and general affairs of powerful noble families) that he would accept a peace proposal if it included the Ōtomo.  Based on this alliance, the Shimazu were able to secure their territory while the Ōtomo were relieved of the threat of attack by the Shimazu and Itō while engaged in battle in the northern portions of Kyūshū.

Invasion of Hyūga by the Ōtomo

In 1577, after a defeat to the Shimazu, Itō Yoshisuke temporarily withdrew from Hyūga and took refuge with the Ōtomo.  Ōtomo Sōrin granted the Itō approximately 300 hectares of land and offered them protection.  Meanwhile, Mera Shirōemon (the lord of Kadogawa Castle), Migimatsu Shirōzaemon (the lord of Shiomi Castle), and Mera Kinouchi (the lord of Yamage Castle) – retainers of the Itō who had surrendered to the Shimazu – appealed to Saeki Korenori (a retainer of the Ōtomo) to serve as a guide for the invasion of Hyūga.  Amidst these circumstances, in 1578, Ōtomo Sōrin and Ōtomo Yoshimune (father and son) opposed the northward advance of the Shimazu and, to enable the return of the Itō clan to Hyūga, decided to lead an expedition to Hyūga with an army of between 30,000 to 40,000 soldiers.  The Ōtomo army separated into two divisions for the gateways from Higo and from Bungo.  Shiga Chikamori, Kutami Akiyasu, and Ichimata Akizane led the division from Higo while Sōrin and Yoshimune led the division from Bungo.  On 2/21 of Tenshō 6 (1578), the vanguard of the Ōtomo army entered Kadogawa Castle in Hyūga.  Members of the Itō band of retainers who had earlier withdrawn to Bungo joined the vanguard and engaged in operations to lure kunishū, or provincial landowners, in Hyūga to their side.

Retainers of the Itō including Nagakura Sukemasa and Yamada Munemasa traversed the Mimi River and encroached on territory in the Shimazu sphere of influence, raising arms at Ishino Castle.  Other members of the Itō band of retainers who promised to collude including Mera Shirōemon, Migimatsu Shirōzaemon, and Mera Kinouchi acts in concert by raising arms and attacked Tsuchimochi Chikashige, the lord of Agata Castle aligned with the Shimazu.  On 3/18, Saeki Nyūdō, Tawara Chikakata, and Takita Shigekane joined the attack against Chikashige while the invasion of Hyūga by the Ōtomo began in earnest.  Chikashige holed-up in Matsuo Castle, but, on 4/15, it fell and, in the course of retreating to Mukabaki, was apprehended and slayed by sword.  The Ōtomo succeeded in controlling the portion of Hyūga lying to the north of the Mimi River while the influence of the Shimazu family receded to the area south of the Mimi River.

In the sixth month, Shimazu Yoshihisa dispatched an army of 7,000 men led by Shimazu Tadanaga as the commmander-in-chief to Hyūga and ordered an attack against Ishino Castle defended by Nagakura Sukemasa and Yamada Munemasa among 600 members of the Itō band of retainers.  This is known as the Siege of Ishino Castle.  On 7/8, the Shimazu army commenced an all-out assault.  Over 500 Shimazu forces were killed in action including Kawakami Norihisa, a vice-general.  Tadanaga, the commander-in-chief, sustained serious injuries when an arrow pierced his left thigh.  Defeated, the Shimazu retreated to Sadowara in Hyūga.  Ōtomo Yoshimune sent a letter of commendation to the garrison of Itō soldiers at Ishino Castle, congratualting the defenders for their victory.  After capturing the territory of the Tsuchimochi, the Ōtomo army decimated all of the shrines and temples, reflecting the will of Sōrin as a Christian daimyō.  According to one theory, Sōrin sought to create a Christian province in Hyūga and his leanings toward Christianity caused friction with his band of retainers.  In the eighth month, Sōrin, accompanied by missionaries, entered Hyūga and established a main base in Mushika.

Counterattack by the Shimazu

As a prelude to offensive operations against the Ōtomo, Shimazu Yoshihisa initiated attacks against the band of retainers of the Itō clan of Hyūga Province.  In the eighth month, Shimazu Yoshihisa and other commanders led attacks against Ueno and Kuma castles in Hyūga defended by Itō band of retainers, capturing both in the ninth month.  Four days after the capture of Ueno Castle, a messenger of Ashikaga Yoshiaki (the fifteenth and final shōgun of the Muromachi bakufu) paid a visit to the Shimazu clan.  The Ōtomo, backed by the Mōri, continued to defend their territory in northern Kyūshū while Yoshiaki took refuge with the Mōri afte rbeing ousted from Kyōto by Oda Nobunaga, establishing an administration in exile known as the Tomo bakufu at Tomo Castle.

Yoshiaki determined that the Mōri would not march to Kyōto owing to the threat posed by the Ōtomo from behind.  In the ninth month of 1578, he issued an official letter to the Shimazu ordering them to capture the territory of the Ōtomo and to halt the invasion of the territory of the Mōri by the Ōtomo.  Shimazu Yoshihisa proceeded to use this letter as justification to further advance to the north, whereupon he had Shimazu Mochihisa lead 10,000 soldiers to head north to assault Ishino Castle defended by the the Itō band of retainers including Nagakura Sukemasa and Yamada Munemasa.  This event is known as the Siege of Ishino Castle.  The fighting commenced on 9/19, and, on 9/29, the defenders yielded to the Shimazu army and proposed a settlement.  After the Shimazu agreed to spare the lives of the members of the garrison, Sukemasa, Munemasa, and other members of the band of retainers vacated the castle and retreated to Bungo.

Course of events

On 10/20, the Ōtomo army based to the north of the Mimi River recommenced a southward advance and laid siege to Taka Castle occupied by the Shimazu army.  While heading out in support of Taka Castle, Shimazu Iehisa, the lord of Sadowara Castle, encountered the forces of Saeki Korenori and was repelled.  The Ōtomo army, wielding several thousand arquebuses and cannons (breech-loading swivel guns) launched three assaults, but Shimazu Iehisa and Yamada Arinobu (the lord of Taka Castle) defended the castle.  On 10/24, Shimazu Iehisa mobilized forces from Satsuma and Ōsumi, leading 30,000 soldiers to deploy from Kagoshima.  After proceeding via Kamiya Castle to Sadowara Castle, the soldiers joined with Shimazu troops in Hyūga to form an army of 40,000 men.  On 11/9, commanders including Shimazu Yoshihisa, Shimazu Mochihisa, Ijūin Tadamune, Uwai Kakuken entered Takarabe Castle and held a war council.  To attack the Ōtomo army based at Matsubara, a diversionary battalion and three ambush battalions traversed the Omaru River and Shimazu Yoshihiro set-up an encampment on the south shore of the Omaru River and confirmed the status of the war.  The diversionary battalion of 300 members assaulted the Ōtomo army at Matsubara and destroyed their supplies.

Alert to the situation, the Ōtomo army rushed forces in support of those at Matsubara, whereupon the diversionary battalion retreated to the location of the ambush divisions.  To reinforce the ambush divisions, Shimazu Iehisa led forces out of Taka Castle to keep in check the main division of the Ōtomo army.  Once the Ōtomo army approached the location of the three ambush divisions, the Shimazu launched an attack, penetrated the base of the Ōtomo at Matsubara, and set it on fire.  The main division of the Shimazu commanded by Shimazu Yoshihiro, Shimazu Mochihisa, Shimazu Tadanaga, and Ijūin Tadamune took advantage of the chaos to cross the river and set-up a position on the southern shore of the Takagi River.  Having suffered losses in this preliminary clash, the Ōtomo dispatched sixteen messengers including Tawara Chikakata to the base of the Shimazu to propose a settlement.  The Ōtomo army split into one faction in favor of continuing the fight and another supporting a settlement.  At a war council, Takita Shigekane advocated for battle, but Chikakata, a general, favored peace negotiations with the Shimazu so did  not go along with the pro-war faction.  Notwithstanding Chikakata’s remonstrations, Shigekane and Saeki Sōten disagreed and launched an attack against the Shimazu army.  The Ōtomo army could not disregard these developments so were forced to fight back against the Shimazu forces.  Tsunokuma Sekisō, a strategist in the Ōtomo army, asserted that “One should not engage in battle when blood red clouds hang overhead.”  Shigekane and Sōten, however, ignored Sekisō’s warning and conflict ensued.  Initially, Sōten, together with Chikakata, argued for restraint and a settlement, but, at the war council, were berated by Shigekane and, for this reason, joined him in the attack.

Upon learning of the war council by the Ōtomo, Shimazu Yoshihisa prepared for battle by positioning forces and leading 10,000 soldiers to Nejirozaka.  In the morning of 11/12, the Takita and Saeki forces initiated an attack against the vanguard troops of the Shimazu army based on the northern shore of the Omaru River.  The main division of the Ōtomo army followed these forces and this battalion of the Shimazu was destroyed during which Hongō Tokihisa and Hongō Hisamori were killed in action.  Next, the Ōtomo army crossed the Omaru River and attacked the main division led by Shimazu Yoshihisa.  Shimazu Yoshihiro, Shimazu Toshihisa, and Ijūin Tadamune intercepted the Ōtomo army while Shimazu Mochihisa, commander of the ambush battalion, planted a battle standard alongside his horse.  The soldiers in the ambush battalion attacked the Ōtomo army while Shimazu Iehisa of Taka Castle and Shimazu Yoshihisa from Nejirozaka joined in the battle.  In an effort to re-group, the Ōtomo army began to retreat, during which some of the troops headed toward Dakekugafuchi where Saeki Sōten drowned in the abyss.  After positions are Kawahara and Nokubi were suppressed, along with the main base, the Ōtomo army began a further retreat in the direction of the Mimi River.  In the course of fleeing, some of the Ōtomo troops were unable to complete the crossing and drowned in the river while others were killed by members of the Shimazu army.  In view of the situation on the battlefield, Ōtomo Sōrin temporarily retreated to Bungo to re-group with his forces.  The Battle of Mimikawa thereby ended in a victory for the Shimazu army.

Consequences

Owing to this battle, the Ōtomo clan lost military power and retainers including, among others, Saeki Korenori, Takita Shigekane, and Kamachi Akimori (a kokujin or provincial landowner, from Chikugo Province).  Consequently, Tachibana Dōsetsu censured Shiga Chikamori (who had been serving as the division commander) for his failings.  An official notice from Ashikaga Yoshiaki was also sent to influential kokujin within the territory of the Ōtomo, causing them to abandon the clan.  This led Akizuki Tanezane (of Chikuzen Province) to resist the Ōtomo and Ryūzōji Takanobu (of Hizen Province) to rebel.  This resulted in a loss of the power and territory of the Ōtomo.  (Apart from the issue as to whether the Shimazu and other clans opposed to the Ōtomo actually desired to cooperate with Yoshiaki.)  Moreover, based on a letter from Shimazu Yoshihisa to Mōri Terumoto dated 12/10 of Tenshō 6 (1578), the Ōtomo were censured for impeding the ability of Yoshiaki to return to the capital of Kyōto.  The Ōtomo stood in opposition to all of the neighboring daimyō families including the Mōri who obeyed Yoshiaki in addition to the Shimazu, the Ryūzōji, and the Chōsokabe who were the subject of his official letter.  The Ōtomo deepened relations with the Oda administration in Kyōto as well as its successor, the Toyotomi administration and,  in an effort to overcome their precarious situation, pursued diplomatic policies in opposition to Yoshiaki.

After a series of battles, the Shimazu eliminated the number of clans rivaling their power in Kyūshū and turned their attention toward strengthening their governance of Satsuma and Ōsumi provinces.  Meanwhile, with support from the Ōtomo diminishing, the Sagara clan of Kuma in Higo Province surrendered to the Shimazu.  Next, a direct attack by the Shimazu against the Aso clan of Aso in Higo forced their surrender.  On 3/24 of Tenshō 12 (1584), at the Battle of Okitanawate, the Nabeshima and Ryūzōji of Hizen Province were defeated by the allied forces of the Shimazu and the Arima clans.  This caused kokujin in Kyūshū to begin to align with the Shimazu.  The Shimazu then commenced an attack against the main base of the Ōtomo in Bungo Province.  Pleas from Ōtomo Sōrin to Toyotomi Hideyoshi led to the Subjugation of Kyūshū by the Toyotomi army and the subsequent defeat and expulsion of the Shimazu from Bungo, with the Shimazu ultimately surrendering to the Toyotomi.

Timeline of events

On 12/10 of Tenshō 5 (1577):  Based on the stratagem of the Shimazu clan, Fukunaga Suketomo, the lord of Nojiri Castle in Hyūga, rebelled and switched his allegiance to the Shimazu so Itō Yoshisuke and Itō Suketake of the Hyūga-Itō temporarily withdrew from Sadowara and Tonokōri castles, moving from Mount Mera via Takachiho to Bungo Province to seek the protection of the Ōtomo clan.

In the first month of Tenshō 6 (1578):  Retainers of the Hyūga-Itō, namely, Mera Shirōemon-no-jō (the lord of Kadagawa Castle), Migimatsu Shirōzaemon-no-jō (the lord of Shiomi Castle), and Mera Kinouchi (the lord of Yamage Castle), made a request via Saeki Korenori (a chief retainer of the Ōtomo clan) for support from Ōtomo Sōrin and Ōtomo Yoshimune to deploy to Hyūga in support of the Itō clan.

On 1/2):  Tsuchimochi Chikashige of the Agata-Tsuchimochi clan based at Matsuo Castle in Agata joined with Shimazu Yoshihisa of Satsuma and abandoned the Ōtomo of Bungo.

On 1/22:  Shimazu Yoshihisa allocated Ishizuka and Sangamyō to the Agata-Tsuchimochi clan.

On 3/15:  The Ōtomo army deployed for an invasion of Hyūga with a force of 30,000 to 40,000 soldiers.  The main division led by Ōtomo Yoshimune set-up its base at Sakekiki in Ume and headed toward Agata via the 梓峠 Pass.  The soldiers comprising the division to attack Agata were from Hiji, Kusu, and Usa.  A detached division went from Higo Province via the Yagamine Pass toward Takachiho and destryed the Yoshimura clan based at Kurotake Castle.

On 4/7:  The Ōtomo army entered Hyūga and established a base at Yashirogahara.  Around this time, the Ōtomo army, in furtherance of their vision to form a Christian province, burned down shrines and templates across the territory of Agata.  This led to the destruction of cultural assets including structures, statues, and ancient texts in northern Hyūga.  As a result, most primary sources from the pre-modern period in northern Hyūga were lost.

On 4/10:  The Ōtomo army captured the base o Tsuchimochi Chikashige at Agata-Matsuo Castle and eliminated the Tsuchimochi clan.  Thereafter, by the eleventh month, Saeki Korenori set-up an encampment at Mushiga.

On 9/6:  On 9/4, a party led by Ōtomo Sōrin departed from Usuki and traveled by sea route to Agata.  He was accompanied by Jesuit missionaries from Portugal including Francisco Cabral, Luís de Almeida, Andrea Doria, and a Japanese individual who adopted the name of Johan de Torres.  In Mushiga, they built an improvised church and residence for priests.  Thereafter, they held daily mass accompanied by organ music.  Sōrin and his wife, Julia, along with other retainers attended the services.

On 9/11:  Ashikaga Yoshiaki, the fifteenth and last shōgun of the Muromachi bakufu, while staying in Bingo and Tomo (in territory controlled by the Mōri), issued an official position to the Shimazu clan requesting their support for his travel to the capital and an invasion and occupation of the territory of the Ōtomo who were opposed to the Mōri.

On 10/20:  The Ōtomo army surrounded Taka Castle.  At this time, Ōtomo Sōrin, together with Francisco Cabral, sojourned in Mushiga.  Shimazu Iehisa entered Taka Castle in Niiroin protected by Yamada Arinobu.  The Ōtomo army attacked by severing provisions.

From 11/9 to 11/12:  The Battle of Takagigawahara occurred (commonly known as the Battle of Mimikawa).  The vanguard forces of the Shimazu army established a position on a plateau to the south of the Omaru River.  The Shimazu army planned (and later succeeded) in colluding with those at the Kawara encampment.

On 11/11:  The Matsuyama encampment was burned down in guerilla warfare.

On 11/12:  The main division of the Shimazu army led by Shimazu Yoshihisa arrived at the Nejirozaka encampment.

The two armies clashed in the environs of Shimozuru in the town of Kijō.  Upon the outbreak of hostilities, Hongō Tokihisa and Hongō HIsamori were killed in action.  As the two armies battled against one another, from the position at Oisesakaue, Shimazu Mochihisa attacked from the east, while soldiers from Taka Castle attachwed from the west, so, in a bid to regroup, the Ōtomo army initiated a retreat toward Bungo.  Some of the units who withdrew in the direction of the Mimi River drowned, giving rise to the event known as the Battle of Mimikawa.

On the evening of 11/12, in an effort to regroup, Ōtomo Sōrin temporarily withdrew from his main base at Mushiga to Bungo.

On 11/14, The Agata-Tsuchimochi clan entered into service for the Shimazu clan and the Shimazu took control of the territory of Agata.