The Oei Rebellion (応永の乱)

The Oei rebellion, which broke out in the sixth year of the Oei era (1399) during the Muromachi period, was a revolt against the Muromachi bakufu (Japanese feudal government headed by a shogun) led by the shugo daimyo (feudal lord) Yoshihiro OUCHI, in which he occupied the city of Sakai (modern-day Osaka) which was eventually brought to ruin.

Background leading up to the rebellion
The Shoguns of the Muromachi bakufu had been courting an alliance with the most powerful of the shugo daimyo, because the shogunate's power and authority was still weak. The third Shogun Yoshimitsu ASHIKAGA, was bent on strengthening shogunal power. He displayed his influence by having the Flower palace rebuilt, and he increased the numbers in his hokoshu (guardian) force, essentially an army he personally commanded, thereby boosting shogunal authority.

Moreover, Yoshimitsu was also bent on weakening the most powerful of the shugo daimyo, and in 1379, he skillfully exploited the conflict between the Hoskawa and Siba families to engineer the overthrow of the powerful Kanrei, Yoriyuki HOSOKAWA (in what became known as the Koryaku coup). In 1389, Yoshimitsu deliberately provoked Yasuyuki TOKI into raising troops and then crushed him (this incident is referred to as Yasuyuki TOKI's rebellion).

And then, in 1391, Yoshimitsu bent his efforts on creating divisions and strife within the very powerful Yamana clan, which held the role of shugo (de facto governor) for 11 provinces and were called "the lords of one-sixth of all Japan;" Yoshimitsu succeeded in bringing about the family's ruin when he had the brothers Tokihiro and Ujiyuki YAMANA strike against their own relatives, Ujikiyo and Mitsuyuki YAMANA. What's more, he then provoked Ujikiyo and Mitsuyuki into raising an army and then destroyed them in turn. In the end, the Yamana clan was left with just 3 provinces under their control (this episode became known as the Meitoku rebellion).

The Ouchi clan, of shugo daimyo rank
The Ouchi clan claimed descent from Crown Prince Imson, son of King Seong of the Baejje kingdom in Korea; indigenous to Suo Province, they became warriors in Japanese society, and reached the rank of gokenin (lower-ranking vassal) under the Kamakura bakufu (Japanese feudal government headed by a shogun). During the period of the Northern and Southern Courts (Japan), they initially sided with the Southern Court, but afterwards switched their allegiance to the Northern Court and fought against the Kikuchi clan and other Southern Court supporters in Kyushu; the Muromachi bakufu rewarded them by appointing them shugo (a position tantamount to military governor) over the provinces of Suo, Nagato, and Iwami.

Yoshihiro OUCHI joined the army of the local military commissioner (tandai) in charge of Kyushu, Ryoshun IMAGAWA, and fought against the Southern Court forces in Kyushu for many years, and as a reward was made shugo over Buzen Province (eastern Fukuoka today) as well. Yoshihiro fought very hard and valiantly during the Meitoku rebellion, achieving a remarkable number of military victories and exploits, so he was also made shugo of Izumi and Kii Provinces. Yoshihiro also had the merit of having helped mediate the unification of the two courts, and reached the point that he was treated with the same honors as a relative of the Ashikaga clan itself.

Making the most of the close proximity of his seat of power to mainland Asia, Yoshihiro also worked to build trade relations between the Ouchi and the Joseon dynasty in Korea, thereby amassing a vast fortune. He made an effort to suppress the wako (Japanese) pirates operating near Korea in compliance with a request by the Joseon king, receiving commendation and praise from the king for his success, and among other overtures, he even sent a messenger to the Joseon kingdom to express his hope that, because the Ouchi had a royal prince of Baekje as an ancestor, he be granted lands in Korea itself; all in all, Yoshihiro had forged a very strong relationship with the Joseon kingdom in Korea.

The Ouchi clan had become so powerful - simultaneously shugo of six provinces, Suo, Nagato, Iwami, Buzen, Izumi, and Kii, and possessing great wealth thanks to their trade - that they were bound to put Yoshimitsu, who was aiming to establish a system of despotic rule by the Shogun, on his guard.

Conflict begins between Yoshimitsu and Yoshihiro
In 1394, Yoshimitsu passed the role and responsibilities of Shogun on to Yoshimochi ASHIKAGA and ascended to Daijo-daijin (Grand minister of state). It goes without saying that Yoshimitsu retained his tight grip on real power, however. In Oei 2 (1395), he resigned from his post as Daijo-daijin and took the tonsure, changing his name to "Dogi" (meaning "the way of righteousness"). Quite a few daimyo and court nobles sought to flatter him and so they all took the tonsure; Yoshihiro also took the tonsure and entered the Buddhist priesthood.

Up until this point, the relationship between Yoshimitsu and Yoshihiro had been very cordial, but in 1397, Yoshimitsu began construction of Kinkaku-ji Temple, and consequently wanted the various daimyo to contribute people towards this project. But among all the daimyo, Yoshihiro alone objected, saying 'Warriors should serve with their bows and arrows,' and refused to comply, incurring Yoshimitsu's displeasure.

At the end of that same year (1397) Yoshihiro was ordered to strike down the Shoni clan, and began fighting with them in Chikuzen Province only to lose his younger brother Mitsuhiro OUCHI in battle, and worse still, no order was given to reward the fallen Mitsuhiro's son for his father's sacrifice, only increasing Yoshihiro's discontent; but what provoked his indignation still more was the rumor that Yoshimitsu had secretly commanded the Shoni and Kikuchi clans to strike down Yoshihiro.

When a Korean envoy arrived in Japan in 1398 and presented Yoshihiro with a vast number of gifts, Yoshimasa SHIBA slandered him to Yoshimitsu, saying 'Now Yoshihiro is accepting bribes from Korea,' and when Yoshihiro heard of this slander he was furious. To Yoshimitsu, who was trying to plan how to proceed in forging trade links with mainland Asia, the existence of someone like Yoshihiro, possessing as he did such a strong bond with Korea, must have been quite obtrusive.

Yoshimitsu repeatedly summoned Yoshihiro to the capital, but rumors had spread that 'You'll be deprived of your governorship (shugo) over Iwami and Kii' or even 'You'll be assassinated on the road to Kyoto,' and hearing these, Yoshihiro felt uneasy.

Trapped into a corner, Yoshihiro made a secret alliance with Mitsukane ASHIKAGA, the kubo (official in charge) of the Kanto region. This secret agreement was reached through the mediation of Ryoshun IMAGAWA, who had unilaterally lost his standing and had been dismissed from his post as tandai (local military commissioner) of Kyushu thanks to Yoshimitsu's machinations. In addition, Yoshihiro contacted several potential allies, including Akinao TOKI of Mino Province, who had been brought to ruin during Yasuyuki TOKI's rebellion a few years earlier, Tokikiyo YAMANA, eldest son and heir of Ujikiyo YAMANA, who had been destroyed during the Meitoku rebellion, Hidemitsu KYOGOKU (younger brother of Takanori KYOGOKU, the shugo of Izumo Province), the warrior monks of Enryaku-ji and Kofuku-ji Temples, and Gonancho (Second Southern Court) forces like the Kusunoki and Kikuchi clans, urging them to raise troops to oppose the shogunate.

The two factions begin to raise armies

On November 19, 1399 (Oei era), Yoshihiro OUCHI led his forces out and arrived at the inlet of Sakai (Osaka) at the border of Izumi Province, and sent his retainer Shinzaemon HIRAI on to the capital, but chose not to go himself. Rumors had sprang up around Yoshimitsu that Yoshihiro was plotting to overthrow him.

Yoshimitsu sent the monk Hogen IYO, who worked for the Cloistered Imperial Prince Sondo of Shoren-in Monzeki (head priest of Shoren-in temple), to Sakai to insist that Yoshihiro travel to the capital, but Yoshihiro refused to comply, saying 'There are some things that will not go according to your will.'
On December 3, Yoshimitsu dispatched the Zen monk Chushin ZEKKAI as his envoy to Sakai.

Yoshihiro met privately with his relatives and chief vassals to decide how to respond. Hiroshige OUCHI, his younger brother, asserted that he obey Yoshimitsu's will and go to Kyoto. Bizen Nyudo HIRAI also argued along the same lines, trying to persuade Yoshihiro that he should re-swear his allegiance and appeal to the Shogun's good graces, for if he did not he would be declared an enemy of the Imperial Court and his whole family would be destroyed. Bungo Nyudo SUGI, on the other hand, argued that the Shogun was already trying to destroy the Ouchi family, and thus advocated armed resistance.

Yoshihiro met with Chushin ZEKKAI. Chushin ZEKKAI counseled him not to believe rumors that the shogunal family was bent on destroying Yoshihiro, and that he should make his way to the capital and apologize to the Ashikaga family for not heeding the earlier summons. Yoshihiro said that he remained grateful for the deep favor the shogunal family had bestowed on him, but also listed his own accomplishments in the battles in Kyushu joining forces with Ryoshun IMAGAWA, in the Meitoku rebellion, in unifying the Southern and Northern Courts, and in the annihilation of the Shoni family before pointing out his dissatisfaction that despite these deeds, the Ashikaga family was trying to remove Izumi and Kii Provinces from his governance, and the fact that his nephew, the son of his younger brother Mitsuhiro - who had died in battle during the recent campaign against the Shoni family - had received no reward for his father's service. Chushin ZEKKAI responded by saying that he saw that Yoshihiro's loyalty was beyond question, and that one cannot trust the rumors the world produces he also reiterated his advice to go the capital, claiming that the reason no reward had been conferred on Mitsuhiro's son was that Yoshihiro had not obeyed the summons to Kyoto in the first place. In response, Yoshihiro declared that he had formed an alliance with the Kanto (the kubo, or shogunal representative of Kanto, Mitsukane ASHIKAGA) to remonstrate with the shogunate's policies, and to go now to Kyoto would violate the terms of that alliance, but said he would be marching on Kyoto together with Mitsukane on the second day of the following month. This was in reality a declaration of war. Chushin ZEKKAI gave up his attempts to persuade Yoshihiro otherwise and returned to the capital.

Yoshimitsu, after hearing Chushin ZEKKAI's report, issued an order to hunt down and destroy Yoshihiro. The vanguard of the army, more than 6000 riders led by Yorimoto HOSOKAWA, Takanori KYOGOKU, and Yoshinori AKAMATSU, immediately rode out from Yodo towards Izumi Province. On December 13, Yoshimitsu set up camp at To-ji Temple, with more than 2000 horsemen under his command. By December 19, Yoshimitsu had advanced as far as Hachiman, where he met up with the main force of 30,000 riders, led by the kanrei Motokuni HATAKEYAMA and former kanrei Yoshimasa SHIBA, and then they all proceeded towards Izumi Province together.

Yoshihiro called a meeting with his advisors where they discussed military strategy. Hiroshige, his younger brother, proposed that they fortify their castles and hold their ground, defending Izumi and Kii Provinces. Bungo Nyudo SUGI advocated that they seize the opportunity they had been given and travel by ship to Amagasaki City, where they could launch a surprise attack against the army at Hachiman and fight one great battle where all would be decided. Bizen Nyudo HIRAI, who had been warning against any effort to overthrow the shogunate for some time now, asserted that any offensive strike was futile, and proposed that they hole up in their castles. Yoshihiro adopted Bizen Nyudo's defensive strategy of entrenching themselves in their castles.

Yoshihiro collected lumber and erected 48 major towers and more than 1000 watchtowers, creating a castle of approx. 1.96 square meters to serve as strong points around Sakai, and began boasting that 'the enemy could not defeat us here even if they brought one million men against us.'
On the other hand, Yoshihiro did make preparations against the likelihood of his death in battle, even going so far as to invite the monk who had previously given him the tonsure to come and perform his funeral service. He also sent both his will and a remembrance of himself to his mother, whom he had left at home in Suo Province, and sent a message to his younger brother Morimi OUCHI to guard the provinces under their control well and fiercely. All of Yoshihiro's followers had also prepared to die in battle.

The assault on the fortifications begins
The shogunal army of about 30,000 horsemen surrounded Sakai and laid siege to it, while at sea, pirates from Shikoku and Awaji Island blockaded Sakai's harbor with a fleet of more than 100 ships. Yoshihiro gathered all available troops at Sakai, and had both Kuro SUGI, who was fighting at Moriguchi Castle, and Bicchu no kami (the governor of Bicchu Province) SUGI, who was deployed at Kamoyama, fall back and join him there. Yoshihiro's army numbered about 5000 men.

On January 3, 1400, the shogunal army all simultaneously let out a battle cry and began a general frontal assault. The Ouchi forces fought back, raining arrows down on the enemy from their watchtowers. On the north, kanrei Motokuni HATAKEYAMA's force of 2000 men broke through Ichinoki and Ninoki gates, pushing their assault as far as Sannoki gate in what developed into a bitterly fought battle that left more than 700 dead or wounded.

Tokihiro YAMANA's 500-man force replaced the Hatakeyama army and pressed the attack, while Bungo Nyudo SUGI and others led a sortie out from the castle to meet them in battle with 500 men. Yoshihiro also led 200 riders over to join the fight. Toshiyasu KITABATAKE, the provincial governor of Iyo, came to reinforce the Yamana army with about 300 men, and was caught in such fierce fighting that Toshiyasu's own son, a major general, was killed.

The armies of the Hosokawa and Akamatsu clans, numbering about 5000, attacked from the south of Sakai, while the Rokkaku and Kyogoku clans pressed the assault from the east. The battle continued into the night, with too many killed and wounded to count.

The anti-Yoshimitsu faction rises up in revolt
Around this time, Akinau TOKI, who had formed an alliance with Yoshihiro, raised an army and invaded Owari Province, penetrating as far as Mino Province. At that point, the shugo of Mino, Yorimasu TOKI, was at the camp of the army fighting against Ouchi's forces, but immediately returned to Mino and smashed Akinao's army.

Ujikiyo YAMANA's eldest son and heir, Tokikiyo, had also allied himself with Yoshihiro, and attacked into Tanba Province, invading the capital (Kyoto) and setting fires there before targeting the shogunal army camped at Hachiman and raiding it with 300 men. Tokikiyo's force smashed the camps of the shogunal army one after the other, but exhausted their strength and were forced to withdraw.

Hidemitsu KYOGOKU raised an army in Omi Province and planned to invade towards the capital. 500 warrior-monks from Onjo-ji Temple burned the Setabashi bridge at Seta and waited to meet Hidemitsu's army. Hidemitsu, out of options, drew up battle lines in Moriyama and prepared for the coming battle. When the Kyogoku force of 1000 men, who had joined the attack against the Ouchi, retraced their steps and neared Moriyama, Hidemitsu, trying to join up with Akinau TOKI, headed for Mino Province, but on the way he became caught in the middle of a farmers' uprising and was routed; Hidemitsu slipped away with just one close retainer and disappeared. Moreover, because Hidemitsu's official government post was "kingo" (saemon no jo under the ritsuryo system), when referring to just his raising of troops it is also called the Kingo Disturbance (kingo sodo in Japanese).

Mitsukane ASHIKAGA, kubo (shogunal representative) of the Kanto, led about 10,000 men into Musashi Province, advancing as far as Koan-ji Temple in the city of Fuchu, but halted his advance after he was warned by the Kanrei of the Kanto, Norisada UESUGI not to continue.

Sakai castle falls
Back in Sakai, morale among the Ouchi forces jumped after they repulsed the general assault launched by the shogunal army. The shogunal forces resolved to attack the city with fire, and having prepared sagicho rockets (a kind of firecracker), they got the road ready before launching another general attack in the early morning of January 25, 1400. Taking advantage of a strong wind, the shogunal forces were able to set fires within the castle, and they pressed their assault furiously, knocking down all the watchtowers they could.

Bicchu no kami SUGI resigned himself to the reality that this day would be his last battle, and threw all his strength into an assault on the camp of Mitsuuji YAMANA, achieving a spectacular death in battle. Yoshihiro, after seeing this, resolved that he would continue in the tradition of general Xiang Hu's glorious death, and make such an end for himself as would ensure his fame for posterity. He cut his way into the battle lines of the shogunal army on the north side of the city, striking left and right with his katana in fierce fighting. Kanrei Motokuni HATAKEYAMA's legitimate son and heir Mitsuie took his force of 200 men and challenged Yoshihiro's advance, but Yoshihiro proved a worthy opponent indeed, fighting back ferociously even though he had a mere 30 men. At that moment, the 200 soldiers from Iwami Province defected and joined the shogunal force. This infuriated Yoshihiro, who attacked the Iwami army with such force that the Iwami army became terrified, broke and scattered.

Yoshihiro continued fighting, attempting to strike down Mitsuie, but the shogunal army surrounded him and launched an unrelenting assault. The number Yoshihiro's soldiers steadily dropped until only one remained, Mori Minbu no jo. Mori Minbu no jo protected Yoshihiro as they cut their way into the enemy battle lines, fighting fiercely until being killed in battle. Alone now, Yoshihiro continued to fight on, trying to kill Mitsuie, but he was surrounded and in the end used up all his strength, letting out a great shout, saying 'Yoshihiro OUCHI, great military commander without peer, now enters the next life. Kill me now, and take me before the Shogun for one last meeting,' and with that was struck down.

When Bungo no kami SUGI, who was reinforcing the south side of the city, was told of Yoshihiro's death, he cut his way into the enemy's formation and died in battle. Hiroshige, who was reinforcing the east side of the city and fighting against the armies of the Imagawa and Isshiki clans, also found his own soldiers' numbers dwindling, and deciding that he had fought as long as he could, he tried to kill himself. But Bizen Nyudo HIRAI stopped him, counseling that he surrender, advice Hiroshige also took.

The rest of the Ouchi army having either escaped or killed themselves, the fortifications of Sakai were taken.

Mitsukane ASHIKAGA, the kubo of the Kanto, had taken his army and marched from Fuchu in Musashi Province as far as the Ashikaga family's private estates in Shimotsuke Province (modern-day Ashikaga City in Tochigi Pref.), but when news of Yoshihiro's defeat and death reached him, he turned back to Kamakura.

Aftermath of the battle
In April, 1400, the Kanto kubo Mitsukane ASHIKAGA presented a prayer-petition to the Grand Shrine at Mishima in Izu Province in which he apologized for double-crossing the shogunate 'in my narrow-mindedness.'
Ryoshun IMAGAWA, the one who had urged Mitsukane to revolt against the shogunate, was made the target of a search and destroy order from the shogunate, and because of this proceeded to the capital and apologized, for which he was granted clemency. Thereafter, he abandoned political life and immersed himself in the composing of waka (classical Japanese poems) and renga (linked verse).

Yoshimitsu stripped the Ouchi clan of their control over the provinces of Izumi, Kii, Iwami, and Buzen. To Hiroshige, who had capitulated, he granted only the provinces of Suo and Nagato. But Morimi, who had been protecting the Ouchi heartlands of Suo and Nagato, refused to accept this and forcefully resisted. Hiroshige, together with shogunal reinforcements, attacked and drove Morimi away, but in 1401 Morimi raised a new army in Kyushu and made another attempt to win back the Ouchi lands, and after several battles between them, Morimi destroyed Hiroshige at Sakariyama Castle (in modern-day Chufu ward of the city of Shimonoseki).

Morimi then extended his military hegemony even further, gaining control as far as Aki and Iwami Provinces. The shogunate, no longer able to avoid acknowledging Morimi's overlordship of these lands, officially granted him the title of shugo over Suo and Nagato Provinces in 1405, and when they added the provinces of Buzen and Chikuzen to his dominion as shugo, he finally swore allegiance to the Shogun again. In this way, the Ouchi clan was able to recover their military strength and rally after being brought once to the brink of ruin.

The Chronicle of the Oei Era (Oei-ki in Japanese)
The events of the Oei rebellion are recorded in "the Chronicle of the Oei Era."