Battle of Okitanawate

沖田畷の戦い

Ryūzōji Clan

Hizen Province

Arima Clan

Shimazu Clan

Date:  3/24 of Tenshō 12 (1584)

Location:  Okitanawate in the northern portion of the Shimabara Peninsula in Hizen Province

Synopsis:  Following the decline of the Ōtomo clan, the Ryūzōji based in Hizen and the Shimazu based in Satsuma were the sole remaining powers vying for control of Kyūshū.  After betraying the Ryūzōji, Arima Harunobu called upon the Shimazu to join forces to confront the Ryūzōji in Hizen.  The wetlands area of Okitanawate on the Shimabara Peninsula prevented the Ryūzōji army from exploiting their larger army.  This resulted in victory for the allied forces of the Arima and Shimazu, while the death in battle of Ryūzōji Takanobu led to the subsequent fall of the Ryūzōji clan.  

Lord:  Ryūzōji Takanobu 

Commanders:  Ryūzōji Takanobu, Nabeshima Naoshige

Forces:  25,000 (other sources note as many as 60,000)

Losses:  Approximately 2,000 including Takanobu

Lord:  Shimazu Yoshihisa

Commanders:  Arima Harunobu, Shimazu Iehisa

Forces:  6,000 (3,000 from each clan; other sources note as many as 10,000)

Losses:  Unknown

The Battle of Okitanawate occurred on 3/24 of Tenshō 12 (1584) on the Shimabara Peninsula in the northern portion of Hizen Province in Kyūshū.  The conflict was waged between Ryūzōji Takanobu, a sengoku daimyō of Hizen, and the allied forces of the Arima and Shimazu clans led by Arima Harunobu and Shimazu Iehisa.  “Nawate” refers to small paths extending between wetlands areas where the battle unfolded.

Background

The Ryūzōji rose from being servants ot the Shōni clan to usurp their lords and become a sengoku daimyō family.  In the era of Takanobu, operating from their base in Saga, the Ryūzōji unified Hizen Province.  In 1570, at the Battle of Imayama, the Ryūzōji defeated Ōtomo Sōrin (Yoshishige), a sengoku daimyō and the twenty-first head of the Ōtomo clan of Bungo Province.  Riding this momentum, the Ryūzōji captured one-half of Higo, Chikuzen, Chikugo, and a portion of Buzen Province.

In 1578, Ōtomo Sōrin led his army southward to Hyūga Province and, at the Battle of Mimikawa, was defeated by Shimazu Yoshihisa.  As a result, the Ōtomo family lost many bushō.  The defeat triggered a succession of departures by members of illegitimate branches of the family as well as members of their band of retainers, leading to a decline of the clan.  This brought to an end an era when the Ōtomo were counted among the three most powerful clans in Kyūshū.  Meanwhile, in the wake of their victory, the Shimazu encroached on the territory of the Ōtomo and confronted the sole remaining power, the Ryūzōji, in a contest for control of Kyūshū.

In 1581, the Shimazu advanced north to Higo Province.  Ryūzōji Takanobu responded by dispatching his lineal heir, Ryūzōji Masaie, and brother-in-law, Nabeshima Nobuo (later known as Naoshige) to subdue Akahoshi Chikataka who was aligned with the Shimazu and forced the surrender of Uchi-no-koga Shigefusa of the Yamamoto District in the northern portion of Higo.  Consequently, kokujin, or provincial landowners, located in the northern portion of Higo came into the service of the Ryūzōji.

After Takanobu learned that Kamachi Shigenami of Yanagawa in Chikugo was conspiring with the Shimazu, he had Ogawa Nobutaka and Tokushima Nagafusa kill Shigenami and his entire family, causing strong opposition among bushi to the action, some of whom abandoned Takanobu.

Prelude to battle

On 3/19 of Tenshō 12 (1584), Takanobu departed from Ryūōsaki having learned that Arima Harunobu betrayed him.  On 3/20, he landed at Kamishiro in the northern portion of the Shimabara Peninsula.  Harunobu requested reinforcements from the Shimazu army located in Yatsushiro.  At the time, the Shimazu were commencing efforts to pacify Higo, but, after the main division of the Ryūzōji army arrived in Shimabara, the Shimazu were forced to respond by sending reinforcements to Harunobu.  If, however, the main division of the Shimazu army moved, although weakened, the Ōtomo would likely advance southward, while Aso Koremitsu and Kai Sōun who killed Sagara Yoshihi in battle were on the move so Shimazu Yoshihisa could not send his large army to Shimabara.  Instead, he dispatched forces commanded by his younger brother, Shimazu Iehisa, along with Ei Hisatora, Niiro Tadamoto, Saruwatari Nobumitsu, Ijūin Tadamune, and Kawakami Tadatomo.  This contingent was smaller than the 5,000 troops in the Arima army.  Fortunately, the Shimazu army arrived on 3/22, the day before the Ryūzōji forces.  Stormy seas caused trouble for the Ryūzōji and also delayed the crossing by the Shimazu which, as a result, could not send a large contingent.

Meanwhile, Nabeshima Nobuo warned his lord, Takanobu, against raising the vigilance of the Shimazu army.  Nobuo advocated for a war of attrition, and to wait until the reinforcements from the Shimazu withdrew to Higo before crushing the Arima.  Owing to his overwhelming military superiority, Takanobu became arrogant and dismissed the counsel of Nobuo.  In terms of military power, the allied forces of the Shimazu and Arima were inferior to the Ryūzōji so Harunobu argued in favor of waiting for the rear guard of the large Shimazu army before engaging in battle, but Iehisa devised a plan to decimate the Ryūzōji army using a proactive defense strategy, deciding upon Okitanawate in the northern part of Shimabara as the battlefield.

At the time, in the area of Shimabara, wetlands and muddy rice fields were spread out in-between the coastline and the foothills of the first chain of mountains.  Moreover, the roads between the mountains and Moritake Castle were very narrow.  In Okitanawate, small footpaths traversed the wetlands.  To block access to the footpaths, and to firmly secure the castle, the allied army reinforced the main gate and built fences, completing these preparations by the evening of 3/23.  The defenders also benefited from the sluggish advance of the Ryūzōji army.  The allied army established its main base at Moritake Castle with Harunobu as the commander-in-chief.  Ijūin Tadamune was positioned with over 1,000 troops along the coastline, 50 members of the Akahoshi clan were inland at the main gate, Shimazu Iehisa’s army was on reserve behind Moritake Castle for ambushes, while Niiro Tadamoto set-up ambushes with 1,000 soldiers in the foothills.  At early dawn on 3/24, the Ryūzōji army reached Okitanawate whereupon Nabeshima Nobuo set-up a camp on the side of the mountains while Takanobu’s second son, Egami Ietane, along with Gotō Ienobu, set-up along the coast.  Meanwhile, the main division led by Takanobu positioned in-between these two forces penetrated into Okitanawate to stage an assault on Moritake Castle.

Course of events

The allied forces of the Shimazu and Arima built barriers in front of and to the north of Moritake Castle and positioned a limited number of troops while, with the exception of the main division of the Arima stationed in the castle, established a defensive line hiding in the shadows of the mountain range and prepared to attack.  Meanwhile, Takanobu climbed Oyama overlooking Moritake Castle and, after viewing the enemy encampment, determined their numbers were low, haughtily assuming that an easy victory was at hand.

Clashes commenced around 8:00 AM.  The Shimazu executed a plan to draw-out the Ryūzōji army so did not counterattack and, instead, feigned a withdrawal in defeat.  As the Ryūzōji army pursued them, the Shimazu rained arrows and arquebus fire on them from the flanks, withering the vanguard of the enemy.  The second division attempted to support them but, owing to the narrow roads with muddy rice fields on either side, struggled to advance.  The allied forces of the Shimazu and Arima enticed the Ryūzōji army to come forward who found themselves unable to maneuver owing to the narrow paths surrounded by rice fields and wetlands.  Arquebus fire halted their progress, causing them to fall into disarray.  To confirm the situation on the front lines of the battle, Takanobu dispatched Yoshida Kiyouchi as a messenger.  So that the troops would continue to attack without hesitation for loss of life, Kiyouchi spoke beyond the orders given by Takanobu.  This incited the commanders who then launched reckless attacks and were subjected to a hail of arrows and fire from arquebuses by Shimazu forces laying in wait.  Caught off-guard, as the Ryūzōji forces entered the muddy rice fields they were cut down by the Shimazu troops.  While some battalions sought to retreat, others attempted to advance, descending into a scene of chaos on the footpaths between the rice fields.  On the coastline along the Ariaki Sea, when 2,000 Egami and Gotō forces in the Ryūzōji army proceeded en masse, Amakusa Izu-no-kami of the Shimazu and Arima allied army bombarded them with two cannons mounted on his ship, imposing casualties and scattering the enemy forces.  The allied army used this as an opportunity to attack the enemy camps with forces led by Ijūin Tadamune along with the main division of the Arima attacking from their positions along the coastline to the main camp of the Ryūzōji.

Around 2:00 PM, while Takanobu was seated upon his camp stool, he was spotted by Kawakami Tadakata of the Shimazu army who attacked and took his head.  Tadakata kept Takanobu’s short-sword as the spoils of war. 

In this way, after luring the enemy forces into unfamiliar terrain, and deploying a battlefield strategy known as tsurinobuse by which the Shimazu drew the enemy forces forward and then attacked from the flanks with troops lying in ambush, the allied forces of the Shimazu and Arima defeated the Ryūzōji despite fielding inferior numbers. 

According to another theory, the individual who killed Takanobu was Manzen Chūbei-no-jō 弘賀.  Amidst the chaos of battle, Takanobu was carried away in a basket by six individuals.  While Takanobu hid among the reeds, he was discovered by the battalion of 弘賀.  Members of the battalion announced there was a message to deliver, but after the six individuals approached, they were suddenly cut-down.  Reciting a Buddhist incantation, Takanobu attempted to crawl away but his head was taken with a sword.

In any event, news that Takanobu had been killed quickly spread across the battlefield.  During the inspection of heads, a retainer of Takanobu named Eiriguchi Nobutsune pretended to be an ally and penetrated the Shimazu camp.  Aiming to kill Shimazu Iehisa, the commander-in-chief, he lunged at Iehisa but only managed to cut his left foot and was then captured and tortured to death.

Aftermath

In this battle, the Ryūzōji family lost many members including, in addition to their commanding generals (Takanobu and Nobukatsu), Ryūzōji Yasufusa, Ogawa Nobutoshi, and senior retainers such as Narimatsu Nobukatsu and Hyakutake Tomokane.  Over 230 members of the clan were killed in action.

After losing Takanobu, the Ryūzōji forces retreated in the direction of their base at Saga Castle in the Saga District of Hizen.  Egami Ietane, who attacked along the coastline, managed to flee the battlefield despite losing some of those under his command including Shigyō Tanekane during the retreat.  The main division led by Nabashima Nobuo collapsed and headed in the direction of Yanagawa.

Takanobu’s lineal heir, Ryūzōji Masaie, joined his grandmother to govern affairs in the province, but amidst rumors that the Shimazu army would come to invade, in 1588, Masaie’s uncle, Ryūzōji Nobuchika, consulted with the chief retainers and called back Nabeshima Nobuo from Yanagawa.  Numerous kokujin formerly under the command of the Ryūzōji abandoned the clan in favor of the Shimazu so that, at once, the power of the Shimazu expanded into Chikuzen and Chikugo.  Thereafter, the Shimazu pursued a course aiming for a hegemony in Kyūshū.

Meanwhile, there are no records of a reward given to Kawakami Tadakata for killing Takanobu.  In this era, even marginal victories were valued where as this was an overwhelming victory so there may have been fear of fueling the resistance and resentment of the defeated forces.  Moreover, the means by which they secretly penetrated the main base of the Ryūzōji to enable the attack against Takanobu may have been regarded as a devious tactic that violated the moral code of the bushō.

Relative strength of armies

With respect to the allied forces of the Shimazu and Arima, Arima Harunobu led 5,000 soldiers which, together with the Shimazu, comprised an army of lees than 10,000 soldiers in total.  A Jesuit missionary from Portugal named Luís Fróis who resided in Japan at the time noted in his chronicle that two large cannons were on ships allied with the Arima, but there was no gunner so a Kafr from Egypt loaded the cannons while another person from the Malabar Coast of India ignited the cannons.  Despite the difficulties of these operations, the cannons fired well.

Luís Fróis further noted, “The enemy forces attacked our enclosed base again.  The forces from Satsuma fought back, but were already fatigued and they were woefully disorganized for the battle.  The Ryūzōji possessed many arquebuses but few arrows, along with long spears and short swords, while the Shimazu forces had few arquebuses, but wielded many arrows, short spears, and very long swords.  The opposing armies did not have a chance to clash with spears, instead, indiscriminately cutting the long spears with their swords while there was no time to load ammunition in the arquebuses so those were not deployed.”  The Shimazu utilized their tactic to draw-in the enemy forces, but the conflict was so violent that neither side could utilize their arquebuses.  The Ryūzōji army fielded more soldiers than the allied forces of the Arima and Shimazu but could not make effective use of their firepower.

An account of the battle in northern Hizen states the Ryūzōji army totaled 57,000 soldiers.  According to records from Satsuma, the total was 60,000.  Luís Fróis noted in his chronicle a total of 25,000 soldiers.

Later, Nabeshima Naoshige, who was originally ordered to suppress Chikugo Province from Yanagawa Castle, was replaced by his father at the castle so he could participate in the battle.  According to the account of Luís Fróis, Naoshige attempted to send 50 ships and 5,000 men to Shimabara Castle, but, owing to the defenses of the Arima and Shimazu army, could not land there and entered Jichū Castle.  Together with the original army of 57,000 soldiers, the combined forces totaled over 60,000.