The Honnō-ji Incident (本能寺の変, Honnō-ji no Hen) was the attempted assassination of Japanese daimyo Oda Nobunaga at Honnō-ji in Kyoto in 1582. Nobunaga was on the verge of unifying the country, but died by seppuku in the unexpected rebellion of his vassal Akechi Mitsuhide.
Nobunaga only had a few guards and retainers with him when he was attacked, ending his Sengoku period campaign to unify Japan under his power. Nobunaga's death was avenged two weeks later when his retainer Toyotomi Hideyoshi defeated Mitsuhide in the Battle of Yamazaki, paving the way for Hideyoshi to complete the unification of Japan.
Mitsuhide's motive for assassinating Nobunaga is unknown, though there are multiple theories for his betrayal.
Background
By 1582, Oda Nobunaga was the most powerful daimyo in Japan. He was pursuing a campaign of unification amid the political upheaval of the Sengoku period. Earlier that year, he had destroyed the Takeda clan, at the Battle of Tenmokuzan, leaving central Japan firmly under his control; his rivals, the Mōri clan and the Uesugi clan, were both weakened by internal strife. The death of Uesugi Kenshin had left the Uesugi clan torn by an internal conflict between his two adopted sons. The Mōri clan was also facing near-certain defeat and had offered to cede five provinces in a peace proposal to Hashiba Hideyoshi. The nearly decade-long Ishiyama Hongan-ji War had already ended with the defeat of the Ikkō-ikki.
It was at this point that Nobunaga began sending his generals aggressively in all directions to continue his military expansion. Nobunaga ordered Hashiba Hideyoshi to attack the Mōri clan in the Chūgoku region; Niwa Nagahide to prepare for an invasion of Shikoku; Takigawa Kazumasu to watch the Hōjō clan from Kōzuke Province and Shinano Province; and Shibata Katsuie to invade Echigo Province, the home domain of the Uesugi clan.
Nobunaga, who was confident of unifying the country after destroying the Takeda clan, returned to Azuchi in high spirits. Tokugawa Ieyasu went to Azuchi Castle to thank Nobunaga for giving him the Suruga province. However, around this time, the Mōri clan launched a large-scale counteroffensive in the Chūgoku region, and Nobunaga received a request for reinforcements from Hashiba Hideyoshi, whose forces were stuck besieging the Mōri-controlled Takamatsu Castle.
Nobunaga immediately ordered Akechi Mitsuhide to go to the Chūgoku region to support Hideyoshi, and he himself followed soon after. Nobunaga began his preparations and headed for Honnō-ji in Kyoto, his usual resting place when he stopped by the capital.
Nobunaga was unprotected at Honnō-ji, deep within his territory, with the only people he had around him being court officials, merchants, upper-class artists, and dozens of servants. He had dispatched most of his soldiers to take part in various campaigns, with only a small force left to protect himself. There was little fear that anyone would dare strike Nobunaga; taking advantage of the weak security measures, Mitsuhide suddenly turned against his master.
Mitsuhide's betrayal
Upon receiving the order, Mitsuhide returned to Sakamoto Castle and moved to his base in Tanba Province. He engaged in a session of renga with several prominent poets, using the opportunity to make clear his intentions of rising against Nobunaga. Mitsuhide saw an opportunity to act when Nobunaga was not only resting in Honnō-ji and unprepared for an attack, but all the other major daimyō and the bulk of Nobunaga's army were occupied in other parts of the country. Mitsuhide led his army toward Kyoto under the order of Nobunaga. It was not the first time that Nobunaga had demonstrated his modernized and well-equipped troops in Kyoto, so Mitsuhide's men marching toward Kyoto did not raise any suspicion. Before dawn, Mitsuhide, leading 13,000 soldiers, suddenly changed course in the middle of his march and attacked Honnō-ji, where Nobunaga was staying.
There's a legend that when crossing the Katsura River, Mitsuhide announced to his troops that "The enemy awaits at Honnō-ji!" (敵は本能寺にあり, Teki wa Honnō-ji ni ari).
However, this story first appeared in Oda Nobunaga-fu (織田信長譜) by Hayashi Razan (1583–1657) then in Nihon Gaishi by Rai San'yō, a kangakusha of the late Edo period, and is most likely a creation, not a statement by Mitsuhide himself.
According to Luís Fróis's "History of Japan" and testimonies from surviving soldiers, Mitsuhide was only the commander of the Oda army's area forces, and since it was the Oda clan to whom the soldiers owed allegiance, he did not reveal his purpose to anyone except his officers, fearing that informants might appear. Even when the attack actually began, the soldiers did not know who they were attacking, and some thought it was Ieyasu.
Chronology of the incident
The situation at the time was recorded by Gyū-ichi Ota, the author of "Shinchō Kōki", who interviewed the ladies-in-waiting who were at the scene soon after the incident.
Nobunaga had come to Kyoto to support Hashiba Hideyoshi and stayed at Honnō-ji on this day. This was because Nobunaga had avoided building a castle in Kyoto so that he could maintain distance from the Imperial Court. Nobunaga had ordered his generals to go into battle, so only about 150 men were escorting him at Honnō-ji. Akechi Mitsuhide was leading 13,000 fully armed soldiers, creating a perfect opportunity for Mitsuhide to attack Honnō-ji.
Honnō-ji was a fortified temple with stone walls and a moat, and it had a reasonable defense capability, but it was helpless when surrounded by a large army.
On that day, Kyoto seemed to be in the midst of bad weather due to the combination of abnormal weather and the rainy season. The attack began early in the morning. Mitsuhide's forces finished encircling Honnō-ji around 6:00 a.m. and began to invade the temple from all sides.
According to Shinchō Kōki, Nobunaga and the pages at first thought that someone had started a fight in the street. But when the enemy raised a battle cry and started shooting, they realized it was a rebellion. Nobunaga asked, "Whose scheme is this?", and Mori Ranmaru replied, "It appears to be Akechi's". Nobunaga did not ask back, but simply said, "There is no need to discuss the pros and cons.There is no choice." (是非に及ばず, Zehi ni oyobazu), and began to fight back with bows and arrows at the edge of the palace. When his bowstring broke, he kept shooting arrows while changing bows, and when he ran out of spare bows, he fought with his spear. When Nobunaga was eventually unable to fight after being hit in the elbow by an enemy spear, he retreated and told the nyōbō-shū there, "I don't care, you ladies hurry up and get out of here". It was said that Nobunaga then entered the back room of the palace, closed the door of the storage room, and committed seppuku in the burning temple. The Akechi forces lifted the siege around 8:00 a.m.
Meanwhile, Oda Nobutada, who was at Myōkaku-ji Temple, received news of Mitsuhide's rebellion and attempted to go to Honnō-ji to rescue his father. However, as he was leaving the temple, Murai Sadakatsu and his sons stopped him. Murai said that Honnō-ji had already burned down and the enemy would soon attack us, and advised Nobutada to hunker down in the fortified Nijō Gosho. Upon entering the Nijō Gosho, Nobutada ordered Maeda Geni to flee with his infant son, Sanpōshi (Oda Hidenobu), going from Gifu Castle in Mino to Kiyosu Castle in Owari. Nobutada had all the people escape, including the kugyō and the nyōbō-shū, and then he began his war council. Some advised Nobutada to escape and head for Azuchi, but he said, "An enemy who has committed such a rebellion will not let us escape so easily. It would be a disgrace for me to be killed by common soldiers while fleeing", and decided to stay in Kyoto and fight. In the meantime, Akechi forces completed the siege of Nijō Gosho, making it impossible to escape. Later, Nobutada committed seppuku. Kamata Shinsuke, who assisted Nobutada in his suicide, hid his head and body according to his instructions.
Aftermath
Akechi Mitsuhide was eager to find Nobunaga's body in the burnt ruins of Honnō-ji, but he was unable to locate it. Due to Nobunaga's body remaining undiscovered, no one knew if he was alive or dead, which created a problem for Mitsuhide. Even though the fate of Nobunaga was uncertain, if there was even a chance he was alive, Mitsuhide was more likely to be defeated. It was incredibly difficult for Mitsuhide to gain support from people who feared Nobunaga's retaliation. Hideyoshi even sent a letter to Nobunaga's vassals claiming that Nobunaga was still alive in order to persuade them to help defeat Mitsuhide. However, if Mitsuhide obtained Nobunaga's head, he could publicly confirm his death and encourage forces to join his side. Meanwhile, Mitsuhide was also using the death of Nobunaga to persuade Oda's vassals around Kyoto to respect his authority. Then, Mitsuhide used Nobunaga's Azuchi Castle east of Kyoto to begin sending messages to the Imperial Court. Mitsuhide was attempting to use these messages to increase his rank and force other members of the Imperial Court to respect him; however, no one responded.
Hashiba Hideyoshi received the first news the day after the incident. Hideyoshi responded by immediately making peace with the Mōri clan, attempting to keep Nobunaga's death under wraps, and returning to the Kinai region with a forced and incredibly fast type of march known as Chūgoku Ōgaeshi (the Great Return from the Chugoku Region). He returned in roughly a week with an army of nearly 30,000 troops over 200 km. Hideyoshi also joined forces with Niwa Nagahide and Oda Nobutaka in Osaka and headed for Kyoto. Using this momentum, Hideyoshi defeated Mitsuhide in the Battle of Yamazaki, and while on the run, Mitsuhide was killed due to an ochimushagari.
The Kiyosu Conference was then held to determine the successor to the Oda clan, consisting of four vassals of the Oda clan, Shibata Katsuie, Niwa Nagahide, Ikeda Tsuneoki, and Hashiba Hideyoshi. Three possible successors were discussed; Nobukatsu, the second son; Nobutaka, the third son; and Hidenobu (Sanhōshi), Nobutada's eldest son, or Nobunaga's three-year-old grandson.
Nobunaga's corpse
After defeating Mitsuhide, Hideyoshi searched for Nobunaga's body but was unable to locate it. In October 1582, Hideyoshi held Nobunaga's funeral at Daitoku-ji Temple in Kyoto. To represent his missing body, Hideyoshi used a life-size wooden statue of Nobunaga, then cremated and put the ashes in an urn.
Without any doubt, the thing Nobunaga feared most while preparing to die was not death, but how his body would be treated. Nobunaga must have understood that if his body had fallen into Mitsuhide's hands, his severed head would surely have been gibbeted, disgraced as a criminal, and that Mitsuhide would use Nobunaga's death as public justification for his rebellion. In case of such a situation, Nobunaga came up with some solutions. He could have had his body cremated so that it could not be identified; instead, he could be buried outside Honnō-ji, or he would have someone he trusts carry it away from the temple, even though Mitsuhide could steal it on the way to a new burial site. There are several theories regarding why no bodies were found in the burnt ruins of Honnō-ji. One theory is that Nobunaga could not be identified due to the bodies being unrecognizable; another theory is that there were simply too many bodies, and a third theory was that the fire was so intense that his body was completely consumed by the flames.
There are also several stories claiming that Nobunaga's body and head were carried out of Honnō-ji. There are a large number of tombs in various parts of Japan said to be Nobunaga's, but there is no evidence of his remains lying inside.
Tokugawa's escape to Mikawa
When Tokugawa Ieyasu heard the news in Hirakata, Osaka, he only had a few companions with him. Ieyasu and his party chose the shortest route back to Mikawa Province by crossing Iga Province despite the danger posed on that route by groups of peasants engaging in ochimusha-gari, a practice of hunting warriors who were cut off from their main force. While it was claimed that such groups were formed for self-defense, in reality, they often robbed and killed defeated samurai or soldiers during conflicts.
Accounts of Ieyasu's journey to Mikawa vary across primary sources such as the Tokugawa Nikki and Mikawa Todai-Hon: