The “Kiyosu Kaigi” was a meeting held at Kiyosu Castle on July 16, 1582, three weeks after the death of Oda Nobunaga at the Honno-ji Incident, and two weeks after the Battle of Yamazaki in which Toyotomi Hideyoshi defeated the troops of Nobunaga’s attacker, Akechi Mitsuhide. The remaining retainers of the Oda clan were hurriedly called together at Kiyosu Castle to determine Nobunaga’s successor and the future of the Oda clan.

Kiyosu Castle, Aichi Prefecture, site of the Kiyosu Kaigi

Nobunaga’s first son and designated heir, Nobutada, had been killed in Kyoto’s Nijo Castle as part of the attack by the Akechi forces.

Being July, it was very hot and humid in Kiyosu. The town’s population had swelled considerably as the various retainers and their armies gathered in the castle town. Tensions were high, with all obviously upset at the death of Nobunaga, and with the uncertainty of the future.

It was a time of confusion.

For most, there was no reason to doubt that Nobunaga’s successor would be contested between his sons, Nobukatsu and Nobutaka. Both were 24 years old, born just 20 days apart to different mothers. Nobutaka was actually born first, but as his mother was of lower social rank than Nobukatsu’s mother, he was given the honor of being named as Nobunaga’s second son, and Nobutaka, the third son. But who to support?

Nobukatsu has been described as an incompetent leader and unpopular among the retainers. He had been adopted as heir to the Kitabatake clan of Ise. Nobutaka was more battle hardened, wiser, more decisive than his brother.

Once all the retainers had gathered, with the exception of Takigawa Kazumasu, who was late, Maeda Toshiie and Sassa Narimasa, who were engaged with the enemy in the field, and Tokugawa Ieyasu, the two-day meeting, said to be Japan’s first major political gathering, began.

Those in attendance included Oda Nobukatsu, Shibata Katsuie, Toyotomi (then still known as Hashiba) Hideyoshi, Niwa Nagahide, Ikeda (Shonyu) Tsuneoki, Maeda Gen’i, and Hori Hidemasa.

According to the Tamon’in Nikki, a diary compiled by monks covering a 140 year long period from 1478 to 1618, following Shibata Katsuie’s nominating Nobutaka, Toyotomi Hideyoshi, it appears, then nominated Nobunaga’s grandson, and the first son of the late Nobutada, the two-year-old Samboshi (later to be named Hidenobu) as rightful heir. This must have been a surprise to most in attendance, although rightful by birth and Oda clan laws. Hideyoshi’s motion was supported by Niwa Nagahide. Four days later, the top four retainers would meet, and with a three-member majority, Samboshi was chosen as leader.

This caused a slight rift between the clan retainers. There were those that supported Shibata Katsuie in his efforts to have Nobukatsu instated as leader, and there were those who believed Hideyoshi was correct in seeking to have Nobunaga’s grandson as clan leader.

How many saw the path Hideyoshi was taking in nominating himself, and the infant boy’s two uncles, Nobukatsu and Nobutaka as guardians? The uncles could not see eye to eye, and that would leave Hideyoshi in the role of de facto leader, ruling for and “advising” the young lord just as generations of the puppet Ashikaga shogunate had been controlled by the Miyoshi and Hosokawa.

After a day of deliberations, the decision to accept Sanboshi was cemented. The following day’s agenda consisted of how Akechi lands were to be divided amongst the retainers, and other property was to be redistributed. A memorial service to Nobunaga was performed, and then Lord Samboshi’s succession ceremony was held.

The Kiyosu Kaigi resulted in a major power shift between the retainers, lessening the influence of Shibata Katsuie, and giving greater control to Toyotomi Hideyoshi. It also saw the decline of the Oda clan. It would not be long before the Oda retainers would split into two definitive factions, and go to war.

Oda Nobutaka gained Mino Province where his brother, Nobunaga’s eldest son, Oda Nobutada, had ruled before his death at the Honno-ji, but this was still far short of what he had hoped to gain. He later allied with Shibata Katsuie and Takigawa Kazumasu to start a war against Hideyoshi, but as Nobutaka was surrounded at Gifu Castle by Nobukatsu, and Katsuie lost the Battle of Shizugatake, Nobutaka soon surrendered. Nobutaka was sent to the Daimidoji at Daimido-Ji Temple of Noma, Chita, Aichi Prefecture, where Minamoto no Yoshitomo had been assassinated at the end of the Heian period. Under pressure from Hideyoshi and Nobukatsu, he committed suicide. Two dates, June 19 and June 21 are given for his death.

The Oda clan’s prized Gifu Castle

Niwa Nagahide, who supported Hideyoshi‘s position, gained Echizen and Kaga Provinces, worth over 1,230,000 koku. He thus became one of the most powerful retainers and daimyo. However, Nagahide died of illness in 1585 without making any impact at all. There is a conflicting record that Nagahide had not died of an illness, but on seeing Hideyoshi gain more power and eclipsing the Oda clan Nagahide had so long served, he felt that he had not lived up for the good of Nobunaga and the Oda clan as a whole and committed suicide.

Ikeda Tsuneoki was given 130,000 koku in Mino Province, in 1583 and became the lord of Ōgaki Castle. In 1584, he took part in the Battle of Komaki and Nagakute on the side of Hideyoshi.

The Battle of Shizugatake

After the Kiyosu Kaigi, and the subsequent breakdown in relations between Nobunaga’s former generals, Maeda Toshiie battled against Hideyoshi’s troops under Shibata Katsuie at the Battle of Shizugatake. After Shibata’s defeat, Maeda Toshiie served Hideyoshi, becoming one of his leading commanders.

Kiyosu Castle

Hideyoshi’s rapid ascension to power can be traced back to the meeting at Kiyosu Castle, and the Kiyosu Kaigi.