Honnō-ji Incident

By 1582, Oda Nobunaga was the most powerful daimyo in Japan and was continuing a sustained campaign of unification in the face of the ongoing political upheaval that characterized Japanese history during the Sengoku period. Nobunaga had destroyed the Takeda clan earlier that year at the Battle of Tenmokuzan and had central Japan firmly under his control, with his only rivals, the Mōri clan, the Uesugi clan, and the Hōjō clan, each weakened by internal affairs. After the death of Mōri Motonari, his grandson Terumoto strove only to maintain the status quo, aided by his two uncles, as per Motonari's will. Hōjō Ujiyasu, a renowned strategist and domestic manager, had also died, leaving his less prominent son Ujimasa in place. The death of Uesugi Kenshin left the Uesugi clan devastated also by an internal conflict between his two adopted sons, weaker than before. The nearly decade-long Ishiyama Hongan-ji War also had already ended with the conclusion of peace.[6]

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.[6]

Nobunaga, confident of unifying the country after destroying the Takeda clan, returned to Azuchi in high spirits. Tokugawa Ieyasu also came 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.[2]

Nobunaga immediately ordered Akechi Mitsuhide to go to the Chugoku region to support Hideyoshi, and he himself was to follow soon after.[6] Nobunaga began his preparations and headed for Honnō-ji temple in Kyoto, his usual resting place when he stopped by in the capital.[2] Ieyasu was advised by Nobunaga to go sightseeing in the Kansai region, such as Kyoto and Osaka, so he parted ways with him and left for Sakai.

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. Nobunaga had only a small force with him, and all the generals under his command were fighting hard in various parts of the country. Taking advantage of this opening, Mitsuhide Akechi suddenly turned against Nobunaga.[2]

Upon receiving the order, Mitsuhide returned to Sakamoto Castle and moved to his base in Tanba Province. Around this time, Mitsuhide had a session of renga with several prominent poets, where he made 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 pretense of following the order of Nobunaga. It was not the first time that Nobunaga had demonstrated his modernized and well-equipped troops in Kyoto, so the march toward Kyoto did not raise any suspicion from Mitsuhide's men. Before dawn, Mitsuhide, leading 13,000 soldiers, suddenly changed course in the middle of his march and attacked Honnō-ji Temple, where Nobunaga was staying.[2][6]

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 appeared first in Oda Nobunaga-fu (織田信長譜) by Hayashi Razan (1583 – 1657)[7] 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 Akechi himself.[8][9] 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, Mitsuhide 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 whom they were attacking, and some thought it was Ieyasu.

The situation at the time was revealed by Gyū-ichi Ota, the author of "Shinchō Kōki," who interviewed the nyōbō-shū[lower-alpha 1] who were at the scene soon after the incident.[10]

Nobunaga had come to Kyoto to support Hashiba Hideyoshi and stayed at Honnō-ji on this day. This was because Nobunaga had not dared to build a castle in Kyoto in order to maintain a distance from the Imperial Court.[4] Moreover, Nobunaga had ordered his generals to go into battle, so only about 150 men were escorting him at Honnō-ji. Akechi Mitsuhide, on the other hand, was leading 13,000 fully armed soldiers. This was a perfect opportunity for Mitsuhide.[2][4] 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.[2][4]

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.[2][4]

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?", 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 the 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[lower-alpha 1] there, "I don't care, you ladies hurry up and get out of here".[11][12] It is 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.[2][6][12] The Akechi forces lifted the siege around 8:00 a.m.[4]

Meanwhile, Oda Nobutada, who was at Myōkaku-ji Temple, received news of Mitsuhide's rebellion and attempted to go to Honnō-ji Temple to rescue his father. However, just as he was leaving the temple, Murai Sadakatsu and his sons rushed in and 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 orders 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[lower-alpha 1], 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 completed the siege of Nijō Gosho, making it impossible to escape. Later, Nobutada also committed seppuku.[5]^: 69[6][4] Kamata Shinsuke, who assisted Nobutada in his suicide, hid his head and body according to his instructions.

Akechi Mitsuhide was eager to find Nobunaga's body in the burnt ruins of Honnō-ji, but he was unable to locate it. Nobunaga's body not being found meant that no one knew if he was alive or dead, creating a problem for Mitsuhide. If by any chance he is alive, the probability of Mitsuhide's defeat increases, and even if it remains unclear whether he is alive or dead, Mitsuhide will find it very difficult to gain support from those who fear Nobunaga's retaliation. In fact, Hideyoshi sent a letter to Nobunaga's vassals, falsely claiming that Nobunaga was still alive and requesting their cooperation in defeating Mitsuhide. If Mitsuhide had obtained Nobunaga's head, he could have made his death known to the public, and some forces might have followed him. If that had happened, he might have defeated Hideyoshi.[3][4]

Mitsuhide tried to persuade Oda vassals in the vicinity of Kyoto to recognize him as the new master of former Oda territories. Then, Mitsuhide entered Nobunaga's Azuchi Castle east of Kyoto and began sending messages to the Imperial Court to boost his position and force the court to recognize his authority as well. However, no one responded to Mitsuhide's call.

Hashiba Hideyoshi received the first news the day after the incident. Hideyoshi immediately made peace with the Mōri clan, keeping Nobunaga's death under wraps, and returned to the Kinai region with an ultra-fast, forced march known as Chūgoku Ōgaeshi (The Great Return from the Chugoku Region). After returning in about a week with an army of nearly 30,000 troops for a total distance of 200 km, Hideyoshi joined forces with Niwa Nagahide and Oda Nobutaka in Osaka and headed for Kyoto. With this momentum, Hideyoshi defeated Mitsuhide in the Battle of Yamazaki. While on the run, Mitsuhide was killed as a victim of ochimusha-gari[lower-alpha 2].[13]

After defeating Mitsuhide, Hideyoshi also searched for Nobunaga's body, but it still could not be found. In October 1582, Hideyoshi held Nobunaga's funeral at Daitoku-ji Temple in Kyoto. In place of his missing body, Hideyoshi had a life-size wooden statue of Nobunaga cremated and put it in an urn in place of his ashes.[4]

Tokugawa Ieyasu heard the news in Hirakata, Osaka, but at the time, he had only 34 companions with him. Ieyasu and his party therefore chose the shortest route back to the Mikawa Province by crossing the Iga Province, which was beyond the reach of the Akechi forces, and then crossing Ise Bay. It is said that Hattori Hanzō, a Tokugawa vassal from Iga, negotiated with Iga ninjas to hire them as guards along the way to avoid the ochimusha-gari[lower-alpha 2]. However, it has been pointed out that this story was written in a historical document compiled in the mid-Edo period and may have been exaggerated. On the other hand, Chaya Shirōjirō, a wealthy merchant in Kyoto, wrote that he went ahead and gave silver coins to local people and asked them to guide and escort the group, which is highly likely to be true since it also appears in Jesuit historical documents of the same period.

Takigawa Kazumasu suddenly faced the assault of the Hōjō clan and lost most of his land there, a defeat that cost him his previous prestige in the Oda clan.

Shibata Katsuie and his forces in the north were bogged down by an Uesugi counterattack in Echizen Province and remained unable to act for quite a while.

The fact that no one else had the chance, resources, or ability to act decisively ensured Hashiba Hideyoshi's supremacy and spiritual inheritance of Oda Nobunaga's legacy.

The Kiyosu Conference was then held to determine the successor to the Oda clan, and four vassals of the Oda clan, Shibata Katsuie, Niwa Nagahide, Ikeda Tsuneoki, and Hashiba Hideyoshi, attended the conference. Three names were mentioned as possible successors: Nobukatsu, the second son; Nobutaka, the third son; and Hidenobu (Sanhōshi), Nobutada's eldest son, or Nobunaga's grandson, who was only three years old. However, Hideyoshi, who had contributed to the defeat of Mitsuhide Akechi, had a great say in the matter, and Hidenobu, whom he recommended, was chosen as his successor. As a result, the Oda clan was weakened, and only six years later, in 1588, Hideyoshi unified the country.[14]

The Honnō-ji Incident is a major historical event known to all Japanese, but no definitive conclusion has been reached regarding Akechi Mitsuhide's motives, and the truth remains unknown. More than 50 theories have been proposed over the years, and new theories emerge with each discovery of a new historical document or announcement of the results of an excavation.[2]

The prevailing theory during the Edo period was that the incident was caused by Mitsuhide's resentment of various unreasonable punishments he received from Nobunaga. The main reasons were as follows.[15]

• He was dismissed as a receptionist for Tokugawa Ieyasu[lower-alpha 3].
• Nobunaga had violated him in various ways[lower-alpha 3].
• His fiefdom in the San'in region was unilaterally confiscated.
• His mother, who was a hostage, was killed because of Nobunaga.

Most of the stories are not from primary sources but from historical documents of the Edo period, so their credibility is low.[15][16]

After World War II, the "ambition theory" developed that Mitsuhide also had ambitions to rule Japan. There also emerged the theory that Mitsuhide was a loyalist to the imperial court or a shogunate vassal of the Ashikaga shogunate. Historian Kuwata Tadachika put forth the reason that Mitsuhide had a personal grudge, and there was another theory that Mitsuhide did not enjoy the cruelty of Nobunaga.[15][17]^: 242

The mastermind theory that someone behind the incident manipulated Mitsuhide Akechi to carry out Nobunaga's assassination is surprisingly new and has emerged since the 1990s. It all started when the well-known medieval historian Akira Imatani published a book advocating a conflict between the Imperial Court and Nobunaga. The theory is that the existence of an emperor with high authority was becoming a hindrance to Nobunaga, who wanted to be an absolute monarch. At the time, when the new emperor was about to ascend to the throne, the emperor system was the subject of much debate in the historical academia. Although Imatani himself did not claim that the Imperial Court was involved in the Honnō-ji Incident, various conspiracy theories were developed, mainly by influential historical researchers who were inspired by Imatani's theory.[15] There are several theories about the mastermind.

• Hashiba (Toyotomi) Hideyoshi theory[18]
  • The reason is that Hideyoshi's Chugoku Ogaeshi (big U turn from Chugoku) was too fast. However, only the cavalry warriors were able to turn back at breakneck speed, and the infantry arrived late. Many of the soldiers did not make it in time for the "Battle of Yamazaki" with Mitsuhide.[15]
• Tokugawa Ieyasu Theory[18]
  • The reason is: "Nobunaga, who was on the verge of unifying the country, felt that Ieyasu, his ally, stood in his way. He planned to kill Ieyasu first. However, Mitsuhide, who was becoming increasingly dissatisfied with Nobunaga's policies, conversely informed Ieyasu of the plot and drew him into his side, thus killing Nobunaga by surprise." It is a leap of faith to assume that Mitsuhide and Ieyasu, who had not interacted with each other before, were able to conspire in Nobunaga's city, Azuchi Castle Town, and there is no historical support for this idea.[15]
• Ankokuji Ekei (the Mōri ) theory
  • The theory is that Ankokuji Ekei, a diplomatic monk of the Mōri , which was facing an existential crisis as Nobunaga himself was about to launch a full-scale offensive, arranged for Nobunaga's assassination on condition of the Mori's full cooperation with Mitsuhide and Hideyoshi, and had it carried out.[2]
• Buddhist power theory
  • The theory that Buddhist powers such as Hiei-zan Enryaku-ji and Ishiyama Hongan-ji, which were suppressed by Nobunaga and held a strong grudge against him, were the masterminds behind the situation.[2]
• The Imperial Court/Kuge Power Theory
  • This is the theory that Prince Masahito, Konoe Sakihisa, Yoshida Kanemi, and others forced Mitsuhide to defeat Nobunaga because Nobunaga forced Emperor Ōgimachi to abdicate. In reality, however, the Imperial Court was rather desperate to curry the favor of its sponsor, Nobunaga, since Nobunaga's financial support had dramatically improved their financial situation, which was in danger. Emperor Ōgimachi was also unable to abdicate due to a lack of funding for the abdication ceremony.[15]
• Ashikaga Shogun (Muromachi Shogunate) Theory
  • The theory is that Ashikaga Yoshiaki, the 15th shogun, exiled by Nobunaga, formed the Nobunaga siege by Mori Terumoto, Uesugi Kagakatsu, and other powerful Daimyo, and forced Mitsuhide to stage a coup d'etat. However, the Shogun did not have much authority at the time, and Uesugi and Mori did not cooperate with Akechi.[15]
• Jesuit Theory
  • The theory is that the Jesuits of the Catholic Church, which dispatched missionaries to Japan, were the masterminds. The Jesuits supported Nobunaga militarily and economically, and Nobunaga also protected Christianity, but Nobunaga tried to become independent from the Jesuits by deifying himself, so the Jesuits had Mitsuhide defeat Nobunaga and then had Hashiba (Toyotomi) Hideyoshi defeat Mitsuhide, according to this theory. However, while it is true that Nobunaga protected Christianity, there is no historical record of the Jesuits assisting Nobunaga on either the Japanese or Jesuit side, and in fact, the finances of the Japanese branch of the Jesuits were so tight that they could not afford to do so.[15]

In the 2010s, a Shikoku theory was proposed that Mitsuhide, who valued his relationship with Chosokabe Motochika, rose up to avoid Nobunaga's attack on Shikoku. Mitsuhide was entrusted by Nobunaga to negotiate with Chosokabe, and the Akechi family and Chosokabe had deep ties in relation to marriage.[6][19]

Besides, there is the theory of preferential treatment for Oda Nobunaga's relatives. The theory is that Mitsuhide felt threatened by the fact that Nobunaga, who had previously adopted a merit-based system for his vassals and had appointed them according to their abilities regardless of their origins, began to favor his relatives, eliminating one vassal after another who had made good achievements, with a view to managing the government after unifying the country.[20] As Nobunaga had sent two senior retainers under him, Sakuma Nobumori and Hayashi Hidesada, into exile for poor performance, Akechi might have thought that he could suffer a similar fate. Akechi was already in his early fifties, and it is not surprising that he was anxious about such a grim future.

Before Akechi began his march toward Chugoku, he held a renga session at the shrine on Mount Atago. The beginning line, Toki wa ima, ame ga shita shiru satsuki kana (時は今 雨がした滴る皐月かな), translates to "The time is now, the fifth month when the rain falls." However, there are several homonyms in the line, such that it could be taken as a double entendre. An alternate meaning, without changing any of the pronunciations, would be: 時は今 天が下治る 皐月かな. Thus it has also been translated as "Now is the time to rule the world: It's the fifth month!" In this case, the word toki, which means "time" in the first version, sounds identical to Akechi's ancestral family name, "Toki" (土岐).[17]

There is no doubt that what Nobunaga feared most when he prepared to die was not dying, but what would happen after death, in other words, 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 and he would have been disgraced as a criminal, and that Mitsuhide would use Nobunaga's death to justify his rebellion by making it public. In such a situation, Nobunaga had only two possible options. Either he would have the body burned so that it could not be identified as Nobunaga's, or would have it buried so Mitsuhide could not find it inside Honnō-ji, or he would have someone he trusted carry it out of Honnō-ji, even at the risk of being stolen by Mitsuhide on the way.[4]

There are several theories regarding the fact that no bodies were found in the burnt ruins of Honnō-ji. One theory is that Nobunaga could not be identified because the bodies were too badly damaged, another that there were too many burned bodies to identify, and a third that the fire was so intense that his body was completely consumed.[lower-alpha 4][4]

There are also several stories that Nobunaga's body and head were carried out from Honnō-ji. There are a number of tombs in various parts of Japan that are said to be Nobunaga's, but there is no evidence that his body or ashes are buried in any of them.[4]

• Honnōji Hotel is a 2017 comedy mystery drama that takes places around the Honnō-ji Incident
• Tainei-ji incident – a similar coup in 1551 where a powerful daimyō of western Japan was forced to commit suicide

• de Lange, William (2020). Samurai Battles: The Long Road to Unification. Toyo Press. ISBN 9789492722232.
• Naramoto Tatsuya (1994). Nihon no Kassen. Tokyo: Shufu to Seikatsusha.