A.  Events

Nobunaga arrived at the Honnō Temple in Kyōto in the early evening on the twenty-ninth day of the fifth month of 1582, accompanied by a small band of twenty to thirty retainers.  After arriving at the temple, he declined visits from court nobles, as he had been very busy during these times, hosting Ieyasu and Anayama Nobutada to thank them for securing Suruga, ordering his third son, Oda Nobutaka, to subjugate the provinces in Shikoku, and instructing Akechi Mitsuhide and other commanders to support Hideyoshi in his battles against the Mōri.  He planned to leave Kyōto on the fourth day of the sixth month to direct plans for the western territories and Shikoku. 

On the first day of the sixth month, he received many visitors, creating the atmosphere of an official residence at the temple.  This was the largest gathering since his last visit to Kyōto in the third month of the prior year.  Nobunaga offered tea and visited with the nobles for several hours, discussing the recent defeat of the Takeda clan as well as upcoming challenges from the Mōri.  Nobutada, his son-in-law, visited from Myōkaku Temple.  Murai Sadakatsu, a court administrator and members of the mounted soldiers staying in Kyōto also paid tribute, although with less formality than the meetings with the local nobility.  Nobutada and his retainers returned late at night to their quarters and Nobunaga retired for the evening.

A disturbance on the temple grounds awoke Nobunaga at the break of dawn.  The unexpected noise also stirred Mori Ranmaru and other attendants, which they initially believed to be a fight between locals.  Then the shrill of a war cry and shooting pierced the morning silence.  Nobunaga had a brief exchange with Ranmaru as to whether it may be a rebellion, noting it may be Akechi Mitsuhide. 

When Mitsuhide attacked, those lodging in the temple were in three groups: Some with Nobunaga, those on watch near the front entrance, and others attending to the horses in a barn.  The men near the front entrance swiftly withdrew to protect Nobunaga.  Those in the barn, including Yashiro Shōsuke, Ban Tarōsaeimon, and Tomo Masabayashi, came out to engage the attackers.  Despite being capable bushi, the attackers outnumbered them.  Shōsuke was a mounted bushi from the Kantō who had supported Nobunaga for several years.

Nobunaga grabbed a bow and arrows, but the string to the bow broke, so he switched to a spear to engage the attackers.  After one round, he went into an inner room and committed seppuku, rather than surrender.  The large main hall was largely empty so the battle soon ended.  The attacking forces then set fire to the temple hall around seven in the morning.

Nobutada lodged in the Myōkaku Temple less than one kilometer away from the Honnō Temple.  Upon hearing of the attack on Nobunaga at Honnō, Nobutada sought immediately to defend his lord, but, soon thereafter, Murai Sadakatsu and his two sons arrived to inform Nobutada that Nobunaga had died and that the attack had destroyed the temple.  Sadakatsu further told him that Mitsuhide and his men prepared next to attack Nobutada, advising him to seek refuge in the nijōgosho, an official residence nearby that offered better protection. Nobunaga had originally funded the building of this residence, occupied by the family of Prince Sanehito.  Tennō Ogimachi occupied the kaminogosho residence.  Some of Nobutada’s retainers urged him to flee.  He chose to fight, but Nobunaga’s younger brother, Nagamasu, fled safely to Azuchi.     

Nobutada went to nijōgosho with a contingent of 500 men, beckoning another five hundred to join who were lodging in other locations in Kyōto.  Mitsuhide’s men surrounded the residence.  Nobutada tried to negotiate with Mitsuhide through Sadakatsu.  Mitsuhide only sought Nobutada, so he allowed the nobility residing in nijōgosho to leave.  Then he launched an attack with forces outnumbering the defenders, who fought valiantly with nothing more than swords.  After several engagements, Mitsuhide’s men broke through the main gate and entered the compound.  Nobutada donned a helmet and fought the attackers with a long sword.  Mitsuhide’s men then attacked the adjacent residence of the Konoe clan.  Clamboring to the rooftop, they used arquebuses along with the bow and arrow to rain fire down on the defenders at nijōgosho.  This took a toll on Nobutada’s forces, so that, before long, few remained. Nobutada then committed seppuku as the clash ended by mid-morning.

B.  Motives

The motives for Mitsuhide’s surprise attack are an enduring mystery; however, the events and circumstances leading to the attack, together with the absence of a follow-up plan, suggest that the coup was an act of revenge.

From his first association with Nobunaga, Mitsuhide had gained stature within the Oda army through his own effort, without the benefit of family ties.  Nobunaga’s policy to promote retainers for merit rather than clan affiliation was a great blessing for a tozama such as Mitsuhide.  In recognition of his achievements, he rose from an ordinary foot soldier to become a senior commander in the Oda army.  Nevertheless, in the few years preceding the coup, Nobunaga had embarked on a major reorganization of his chief commanders.  As retribution for failing to pacify the adherents of the Hongan Temple, he banished Sakuma Nobumori, who had enjoyed the status of head military commander, together with his son.  He then removed other important retainers such as Hayashi Hidesada, Andō Morinari, and Niwa Ujikatsu.  Mitsuhide may himself have feared this fate, not for failing to carry out his duties, but for having acquired too much power, and, in the eyes of Nobunaga, posing a threat to Nobunaga’s appointed successor, Nobutada.

Mitsuhide’s rivalry with Hideyoshi jeopardized his future in the clan.  Mitsuhide had made tremendous progress compared to his pre-clan days as a wayfarer, but he aspired to more.  Meanwhile, Hideyoshi had also risen from a lowly foot soldier to become a leading member of Nobunaga’s inner circle.  Unlike the dark and sensitive demeanor of Mitsuhide, Hideyoshi evinced a natural appeal and self-effacing character that endeared him to Nobunaga.  Meanwhile, in the period leading up to the coup, Nobunaga ordered Mitsuhide to leave Tanba and support Hideyoshi in his bid to take Takamatsu Castle in Bittchū Province.  This placed Mitsuhide in a subordinate role while Hideyoshi basked in the glory of the impending victory.  Mitsuhide foresaw that if Hideyoshi succeeded in battle against the Mōri, Hideyoshi would at once rise above him in stature within the clan.  In an attempt to consider how he could improve his position, his pent-up frustration began to take over.  With the Oda army engaged in battles in the northern and western regions, Mitsuhide realized the looming vulnerability of Nobunaga while lodged at Honnō Temple with his small contingent. 

Mitsuhide knew well that to overthrow Nobunaga and become the supreme commander required the ability to capture the allegiance of the vast Oda army.  Nobunaga commanded his men through the artful use of fear.  Hideyoshi used charm, and Ieyasu drew strength from the admiration of those around him.  Mitsuhide, however, did not possess the personal qualities that attracted a large following of supporters.  Without an ability to attract a large base of support, any attempt to defeat the remaining clans, including the Mōri, the Uesugi and the Hōjō, would certainly fail. Moreover, Mitsuhide lacked a plan of action following the coup that would be essential to secure his reign.  A pensive man, Mitsuhide would not have carried out the coup for purposes of seizing power without a follow-up plan to cement his control. In his chronicle “Nihonshi,” a Jesuit missionary named Luís Fróis residing in Japan during this period refers to a rumor that Nobunaga had mistreated Mitsuhide, thus inviting revenge.  Flores also surmised that Mitsuhide had the desire and ambition to be a leader, motivating him to attempt to usurp his lord.  Flores had personally met Nobunaga and was a witness to events of the era, so his chronicles are considered highly credible.

In the course of time, Nobunaga had managed to create no small number of enemies, but there is scant evidence of a supporting cast in the coup.  Mitsuhide may have known that the Ikai clan of Ōmi would stand behind him.  At the time of the coup, a trusted adviser named Saitō Toshimichi was hiding in the town of Katata in Ōmi.  This was the stronghold of the Ikai clan and served as the focal point for the dogō network in Ōmi. These dogō were the chief rivals of Nobunaga in a struggle for control of Ōmi, and Nobunaga had sought to undermine their network by dividing the province among several of his commanders.

Toshimichi vacated his position as a retainer of Inaba Yoshimichi to serve Mitsuhide.  Later, Nobunaga ordered Mitsuhide to return Toshimichi to the service of Yoshimichi, and the refusal of Mitsuhide to obey invited a reproach that strained their relationship.  The western advance by the Oda forces resulted in a predicament for Mitsuhide and Toshimichi.  In the fifth month of 1582, Oda Nobutaka commandeered the dogō of Tanba Province for a campaign against Chōsokabe Motochika, daimyō of Tosa Province on the island of Shikoku.  Nobunaga issued these orders despite the progress that Mitsuhide had been making in his peace negotiations with Motochika, who happened to be married to the younger sister of Toshimichi and maintained close ties with Mitsuhide.  The orders from Nobunaga compelled Mitsuhide and Toshimichi to choose between abandoning Motochika or conspiring against the invasion by Nobutaka.

Mitsuhide may have orchestrated the coup in concert with Ashikaga Yoshiaki.  Mitsuhide served Yoshiaki, who associated with the Court, kuge, temples, and daimyō that opposed Nobunaga; or, he may have toppled Nobunaga in an attempt to preserve this old power structure and to oppose the ascendancy of Nobunaga for reasons tied to the legacy of the Taira and Minamoto clans.

C.  Fleeting Glory

After the coup, Hideyoshi rushed from the western region to engage Mitsuhide at Yamazaki.  Mitsuhide and his forces were soon overwhelmed, and he fled to Ogurusu, where he met an untimely demise at the hands of local residents.

Soon thereafter, Nobunaga’s inner circle of commanders held a meeting at Kiyosu Castle to determine who should be the successor.  The men split into two parties.  One group, headed by Hideyoshi, supported the three-year-old Hidenobu, the lineal heir to Nobutada.  Owing to his age, this meant that Hideyoshi himself wanted to succeed Nobunaga.  Shibata Katsuie headed the opposition in support of Nobunaga’s third son, Nobutaka.  The meeting ended without a clear resolution to the issue of succession, so the tumult did not end until battles between the remaining commanders yielded a victor.  In 1584, Hideyoshi finally defeated Katsuie at the Battle of Shizugatake to become the undisputed successor to Nobunaga.