In October of the 10th year of Emperor Tenji’s reign (671), Prince Oama left the Omi Otsu Palace and headed for Yoshino.
Prince Oama was the younger brother of Emperor Tenji, sharing the same mother.
He was a prominent member of the imperial family who had long supported his brother’s regime, but in the latter years of Emperor Tenji’s reign, his son, Prince Otomo, had come to the forefront of the government.
Prince Otomo was born in the 4th year of the Taika era (648). In January 671, while still in his early twenties, he was appointed as the Grand Minister of State.
Soga no Akae was appointed as the Minister of the Left, and Nakatomi no Kane as the Minister of the Right, forming a political structure centered around Prince Otomo in the Omi court.
That same autumn, as Emperor Tenji’s illness worsened, he summoned Prince Oama.
According to the Nihon Shoki, Emperor Tenji intended to entrust future affairs to him, but Prince Oama declined the throne, suggesting instead that Empress Yamato-hime be enthroned and that Prince Otomo handle state affairs.
He then expressed his wish to become a monk, shaved his head that very day, and handed over his personal weapons to the authorities.
On October 19th, Prince Oama departed from Omi.
Soga no Akae and Nakatomi no Kane, among others, saw him off as far as Uji, and the next day he entered Yoshino.
The Nihon Shoki recounts that people in Omi remarked at the time,
“It is like releasing a tiger with wings.”
Given that the chronicles were compiled from the perspective of the eventual victor, Emperor Tenmu, this conversation cannot be taken as a verbatim record of the day.
Nevertheless, Prince Oama’s withdrawal from the Omi court to Yoshino in the autumn of 671 marked a significant turning point leading to the internal conflict the following year.
Prince Otomo and Prince Oama
On December 3rd of the same year, Emperor Tenji passed away at the Omi Otsu Palace.
Prince Otomo, along with Soga no Akae and Nakatomi no Kane, took charge of the Omi court’s affairs.
In later years, Prince Otomo was posthumously given the title of Emperor Kobun, but the Nihon Shoki does not contain any record of his enthronement.
Whether he was officially emperor during the Jinshin War has been debated for centuries, so we refer to him here as Prince Otomo.
Prince Oama remained in Yoshino. He did not immediately raise an army following Emperor Tenji’s death.
From the end of 671 to the early summer of 672, there were no major battles between Omi and Yoshino.
During this time, Prince Oama’s sons, Prince Takachi and Prince Otsu, remained in Omi.
Prince Oama was surrounded by retainers in Yoshino.
In Mino and Ise, there were lands and people connected to Prince Oama from earlier times, and these ties would later become evident during his uprising.
Gathering of People in Mino and Owari
Around May 672, information about the movements of the Omi court reached Prince Oama.
According to the Nihon Shoki, laborers were being gathered in Mino and Owari under the pretext of constructing Emperor Tenji’s tomb.
These individuals were reportedly being armed.
There were reports that surveillance was set up on the road from Omi to the capital of Yamato, and that Prince Oama’s retainers were being prevented from transporting provisions at Uji Bridge.
Prince Oama interpreted this as an indication that the Omi court intended to attack him.
Whether this information genuinely indicated preparations for an attack on Prince Oama or was organized by the Nihon Shoki to justify his uprising is uncertain.
However, judging by the movements of both factions leading up to the war, it is certain that tensions between Omi and Yoshino had significantly escalated by early summer 672.
The Jinshin War is not merely a straightforward rebellion by Prince Oama against Prince Otomo’s succession to the throne. The origins of this conflict continue to be a subject of scholarly research.
On June 22, Prince Oama took his first concrete military action.
June 22: Sending Three Envoys to Mino
Three individuals were dispatched from Yoshino: Murakuni no Muraji Otoko, Wani no Omi Kimite, and Mige no Kimi Hiro.
Their destination was Mino Province.
The trio was tasked with delivering Prince Oama’s orders to Omi no Obito Hinoji, the Yumu Commander of Anpachi District, to first mobilize the troops of Anpachi District.
They were further instructed to gather forces through the provincial governor of Mino and quickly block the Fuwa Road.
Anpachi District corresponds to the southwestern part of present-day Gifu Prefecture.
This area contained Prince Oama’s Yumu lands.
Yumu refers to lands and households that served as the economic foundation for the imperial family, and Omi no Obito Hinoji was involved in their management.
Prince Oama did not send envoys to an unfamiliar land but relied on individuals with whom he had established connections to mobilize troops.
The orders given to the three included “block the Fuwa Road.”
In later times, this region became home to one of the three major checkpoints of the Ritsuryo state, the Fuwa Barrier.
However, it cannot be assumed that the institutionalized Fuwa Barrier existed in its later form in 672.
The Sekigahara Town History treats the Jinshin Chronicles’ account of “blocking the Fuwa Road” as a separate historical source from the later establishment of the Fuwa Barrier.
Controlling this road near the border of Omi and Mino would hinder the movement of forces heading east from Omi or west from the eastern provinces.
At this point, Prince Oama himself remained in Yoshino.
June 24: Departing Yoshino
Two days after sending the three envoys to Mino, on June 24, Prince Oama also left Yoshino.
In the calendar of that time, June 24 corresponds to July 24 in the Julian calendar and July 27 in the Gregorian calendar, which is commonly used today. The march took place in the heat of summer.
The number of people accompanying him at the start was not large.
The Nihon Shoki lists names such as Prince Kusakabe and Prince Osakabe, along with Muraji no Okimi, Agata Inukai no Muraji Ootomo, Saeki no Muraji Oome, Otomo no Muraji Tomokuni, Wakasakura no Omi Iose, and Fude no Kubi Nemaro, totaling over twenty individuals.
They were joined by Princess Uji no Sakanoue, who would later become Empress Jito, and over ten court ladies.
The Nihon Shoki also conveys the hurried nature of their departure.
Prince Oama’s horse was not ready in time, so he initially left Yoshino on foot.
Along the way, he rode on Agata Inukai no Muraji Ootomo’s horse, and it was not until they reached the vicinity of Tsuburakawa that his own horse caught up.
It would be difficult to describe this group as a fully organized army from the outset of their uprising.
As they advanced eastward, they would gather more people and horses.
Acquiring Horses in Uda
The group proceeded from Yoshino to Uda.
Near Usuki in Uda, they were joined by Otomo no Makita and others, and in Kamura Village, they encountered over twenty hunters led by Otomo no Kimi Ooku.
The Nihon Shoki records that these individuals also followed Prince Oama.
Further along near the Utano district, they encountered a group of horses transporting rice from Ise.
They unloaded the cargo and had those who were on foot mount the horses.
The group then hurried eastward.
By nightfall, they reached the plains of Uda.
The mountain paths were dark. According to the Nihon Shoki, they broke down village fences to use as torches, relying on the fire to navigate through the night.
They set out for Iga the same day they left Yoshino.
No One Joined at Nabari
By midnight, the group had entered the area around Kakino, present-day Nabari.
There, they set fire to the relay station.
Relay stations were facilities that provided horses and supplies to official messengers traveling along the state roads, serving as crucial hubs for communication and movement for the Omi court.
The Nihon Shoki records that Prince Oama’s group burned down relay stations as they advanced.
At Nabari, they attempted to recruit soldiers from the surrounding area.
The results were not promising.
The Nihon Shoki states that not a single person responded.
In the summer of 672, the court in Omi, which had inherited the regime of Emperor Tenji, was in power.
Prince Oama, a royal family member residing in Yoshino, was uncertain about which side would ultimately prevail.
Joining Prince Oama at that stage would be seen as rebellion against the Omi court.
For people unaware of the eventual outcome, it was not an easy decision to make.
As they moved near Yokogawa, the Nihon Shoki notes that dark clouds appeared in the sky.
Prince Oama performed a divination himself, concluding that although the realm would be divided, he would ultimately gain control.
The image of Emperor Tenmu as knowledgeable in astronomy and divination is depicted from the outset of Volume 28 of the Nihon Shoki.
This divination should be read as part of the narrative in the Nihon Shoki that later celebrates Emperor Tenmu as the victor.
Hundreds Join in Iga
By dawn, the group had entered Iga Province.
While no one joined them at Nabari, the situation in Iga was different.
According to the Nihon Shoki, district officials from places like Ahai District joined with their soldiers, numbering in the hundreds.
On the morning of June 25, the group advanced to Tsuge, near present-day Iga City.
There, they met up with Prince Takeda, who had escaped from Omi.
Prince Takeda was the eldest son of Prince Oama. He was accompanied by Minabe no Oi, Sakanoue no Okimaro, and Furuichi no Kuromaro.
Father and son then crossed the Suzuka Mountains into Ise.
It was only the second day since they had left Yoshino.
Blocking the Suzuka Mountain Path with 500 Men
Upon entering Ise, they were welcomed by the provincial officials Miyake no Muraji Ishitoko, Miwa no Kimi Koshikubi, Tanaka no Omi Ashimaro, and Takata no Kubi Arinaka.
Prince Oama was able to gather a substantial force here as well.
According to the Nihon Shoki, 500 men were dispatched to guard the Suzuka mountain path.
In Mino, Murakuni Oyori and his group had already set out towards the Fuwado Road.
In Ise, the Suzuka Road was blocked.
As Prince Oama’s party continued northward, they prepared for the possibility of being pursued from behind by forces from the Omi side.
The weather took a turn for the worse that day.
Marching through the intense thunderstorm, the group was soaked to the bone and shivering with cold by the time they reached Mie County House.
There, they set fire to a building to warm themselves.
In modern terms, this would have been late July.
Even so, the continuous day-and-night march through the torrential rain must have been a grueling ordeal for the party.
June 26: Worshiping Ise Grand Shrine from Tokigawa
On the 26th, Prince Oama advanced to Asake County.
According to the Nihon Shoki, he worshiped Amaterasu Omikami from the banks of the Tokigawa River along the way.
This scene is well-known for its significance in understanding the later relationship between the Tenmu and Jito courts and Ise Grand Shrine, but it’s important to remember that the Jinshin Chronicle itself was written with an awareness of Emperor Tenmu’s legitimacy.
In Asake County, another prince joined the group.
It was Prince Otsu.
Having left Omi, Prince Otsu arrived to join his father, aligning with Prince Oama alongside Prince Takichi, who had already joined earlier.
At that time, a fast horse arrived from Mino.
Murakuni Oyori reported that he had successfully gathered troops.
The Nihon Shoki records that 3,000 men were assembled to block the Fuwado Road.
The orders given on June 22 had materialized into actual military strength just four days later.
Prince Oama sent Prince Takichi ahead to Fuwado.
Simultaneously, he dispatched Yamashiro no Obito Oda and Ato no Atae Akafu to the Tokaido, and Wakasakura no Obito Iose and Haji no Muraji Mate to the Tosando, to request troops from the provinces along the way.
Prince Oama himself entered Kuwana.
The Omi Court also sought troops from the eastern provinces
The Omi Court had also begun to gather forces.
They sent envoys to the eastern provinces to mobilize troops for the campaign against Prince Oama, as recorded in the Nihon Shoki.
However, the envoys sent east by the Omi side were captured near Fuwado by Prince Oama’s forces.
Prince Takichi delivered this news to Prince Oama.
The recruitment of troops in Mino and the blockade of the Fuwado Road, initiated two days before Prince Oama left Yoshino, now clashed with the Omi side’s attempt to mobilize the eastern provinces.
Whoever controlled Fuwado would directly influence the ability to send eastern troops to the battlefield.
June 27: Prince Oama enters Fuwado
Summoned by Prince Takichi to come closer to the army, Prince Oama left Usano Sasanami no Himemiko and others in Kuwana and headed west.
As he approached the vicinity of Fuwado County House, troops from Owari joined the ranks.
They were led by Owari Province Governor Koshikabe no Muraji Sukekake.
The Nihon Shoki records the number of troops as 20,000.
It is not possible to take these numbers as literal figures.
Regarding the armies of the 7th century, there is no way to verify the 20,000 troops through rosters or logistical records, and the troop numbers in the Nihon Shoki include expressions typical of historical texts.
From historical sources, it is safe to conclude that a very large force from Owari joined Prince Oama’s side.
Prince Oama divided the troops that joined him and had them guard various routes.
At that time, Prince Takechi had already gathered his forces around Fuwa.
Establishing a Temporary Palace at Nogami
Prince Oama entered Nogami in Mino and established a temporary palace there.
This is in the area around present-day Sekigahara Town in Gifu Prefecture.
Prince Takechi stationed his forces nearby at Wazuka.
The Nihon Shoki also records conversations between father and son.
Prince Oama remarked that while the Omi Court had powerful retainers including the Ministers of the Left and Right, his own side was composed only of young men.
Prince Takechi offered to lead the army.
It is said that Prince Oama entrusted military command to Prince Takechi.
While the exact words of the conversation cannot be taken as historical fact, it is evident from the subsequent course of battles that Prince Takechi played a central role in Prince Oama’s army during the Jinshin War.
On the 28th, Prince Oama went to Wazuka to inspect the troops.
On the 29th, more soldiers were gathered, and Prince Takechi was given command.
Around the same time, in Yamato, Otomo no Fukei took action.
He caused confusion among the Omi Court’s forces stationed in Asuka, took control of the troops, and joined Prince Oama’s side.
Preparations for battle began to advance in both Mino and Yamato.
Forming an Army in a Few Days After Leaving Yoshino
When Prince Oama left Yoshino on June 24, he was accompanied by only a little over twenty men and about ten court ladies.
Even his own horse was not ready for departure.
In Uda, hunters were recruited, and pack horses were used. In Nabari, attempts to recruit soldiers met with no response.
Upon entering Iga, several hundred people joined, and he met up with Prince Takechi.
In Ise, local officials welcomed him, and 500 men headed for the Suzuka mountain path. Meanwhile, Murakuni no Oyori and others gathered 3,000 men in Mino, blocking the Fuwa route.
On the 26th, messengers were dispatched to the Tokaido and Tosando regions.
The Nihon Shoki records that on the 27th, forces from Owari joined.
These are not records of a single army moving under Prince Oama’s command from the start.
Individuals managing the Yumo in Mino, Murakuni no Oyori who went ahead, the district officials of Iga, the officials of Ise, Prince Takechi, and the forces from Owari—all of these people moved from different locations and connected with Prince Oama within a few days.
The Omi Court also sought to gather troops from the eastern provinces.
By the time their messengers reached Mino, the Fuwa route was already secured by Prince Oama’s forces.
On July 2, Prince Oama dispatched the assembled army in two directions.
One towards Omi.
The other towards Yamato.
The hurried march that stretched from Yoshino to Fuwa comes to an end here, and the Jinshin War enters a new phase where forces clash across various locations.
Nara Mountain, Hashi Tomb, Kurareki, Omi Nagara.
Finally, both armies collide at Seta Bridge, right in front of Prince Otomo’s headquarters at Omi Otsu Palace.
The Jinshin War and the Battle of Sekigahara [ Kazuto Hongo ]
