🔶My Favorite Nara: The Toritaniguchi Kofun, the Tragic Prince Otsu Buried in the Mountain Where the Sun Sets

Do you know what the photo in the title is?
It is closed off by a rugged, iron-grille-like door, making it look like a prison or something similar, but it is actually the Toritaniguchi Kofun located at the foot of Mount Nijo.

If you are a history buff, you may have heard the story that the handsome hero Prince Otsu was buried at the summit of Mount Nijo after meeting a tragic end. While the Imperial Household Agency designates the Futagami-yama tomb at the summit as Otsu's grave, recent investigations have made the theory that this Toritaniguchi Kofun is his true burial site quite compelling.

In this article, we will take a look at Mount Nijo and Prince Otsu.

The Birth and Siblings of Prince Otsu

Prince Otsu was the son of Emperor Tenmu and Princess Ota.
Princess Ota was the daughter of Emperor Tenji (Tenmu's older brother) and Ochi-no-Iratsume of the Soga clan, making her a full sister to Uno-no-Sarara, who would later become Empress Jito.

Emperor Tenji, before his accession, was known as Prince Naka-no-Oe, who carried out the Isshi Incident with Nakatomi no Kamatari to lay the foundations for a centralized government. He had many wives and children, and it is said that he married off his daughters with political intentions.

Both Princess Ota (the elder sister) and Princess Uno-no-Sarara (the younger sister) married Prince Oama (later Emperor Tenmu), who was Tenji's younger brother. Both consorts bore children; Princess Ota's son was Prince Otsu, and Uno-no-Sarara's son was Prince Kusakabe.

Emperor Tenmu also had many other princes.
In addition to Prince Otsu and Prince Kusakabe, there were Prince Takechi, Prince Osakabe, Prince Toneri, and Prince Niitabe, all of whom were in line to succeed Tenmu.

What kind of person was Prince Otsu?

In terms of succession to the throne after Emperor Tenmu, Prince Otsu and Prince Kusakabe, both of whom had parents who were direct descendants of emperors, were equally at the top of the list.
Since Kusakabe was one year older, they were roughly of the same generation.

Regarding Prince Otsu's character, the Nihon Shoki records: 'His demeanor was outstanding, and his voice was excellent, bright, and loud. As he grew up, he understood affairs and possessed talent and learning. He loved writing, and the prosperity of poetry in this country began with Otsu.' The Kaifuso, considered the oldest collection of Chinese poetry in Japan compiled during the Nara period, also states: 'His physique and appearance were robust, and he was magnanimous. He loved martial arts and was skilled with the sword. He did not adhere to rigid rules, and despite being a prince, he was humble and treated scholars with great respect. He was loved and trusted by many people.'

It seems he was recognized as a person of outstanding appearance, character, and talent.

On the other hand, there are no particular records regarding the character of Prince Kusakabe, so it is not well known what kind of person he was.

The Yoshino Covenant by Emperor Tenmu

Following the Jinshin War in 672, Prince Oama ascended the throne as Emperor Tenmu.

In 679, Emperor Tenmu, his consort Uno-no-Sarara, and six princes made a royal visit to Yoshino.
On that occasion, to ensure that his brothers would not fight over his succession, he had the princes swear to decide on the next emperor and to cooperate with one another.
This is the 'Yoshino Covenant'.

Having been forced into a gruesome struggle with his own kin over the throne, Tenmu likely did not want his sons to repeat the same mistake.

Present at this covenant were Tenmu's sons—Takechi, Kusakabe, Otsu, and Osakabe—as well as Tenji's sons, Kawashima and Shiki. And it was Kusakabe who was promised to be the next emperor.

Prince Otsu's achievements and the passing of Emperor Tenmu

While Otsu and Kusakabe were equal in terms of lineage, the main reason Kusakabe was designated as the next emperor, or Crown Prince, was likely the difference in whether they had someone to support them.

In the case of Prince Kusakabe, he had the powerful backing of his mother, Uno no Sarara, who would later become Empress Jito.

On the other hand, Otsu's mother, Princess Ota, had already passed away when Otsu was four years old. Although he had an older sister, Princess Oku, she had been sent to Ise as the first Sai-o (Imperial Princess serving at Ise Shrine), leaving Otsu to forge his own path alone.

As mentioned earlier, because Otsu was a person of exceptional talent, his abilities and character were recognized, and in 683, he began to participate in politics alongside Kusakabe.
Even with the 'Yoshino Covenant' in place, it was inevitable that Otsu and Kusakabe, who originally had equal lineage, would be compared by those around them once they were on the same playing field.
There may have been complex emotions between them.

Amidst this, Emperor Tenmu passed away in 686.

Prince Otsu, suspected of treason, commits suicide at home

Just three weeks after the death of Emperor Tenmu, Prince Otsu was arrested on suspicion of treason, and the following day, he committed suicide at his home in Osada (present-day Sakurai City).

The Nihon Shoki records that his consort, Princess Yamanobe, ran barefoot with her hair disheveled to follow him in death, and that those around them who witnessed this scene wept in sorrow.

The 'Kaifuso,' mentioned earlier, states that this arrest was due to a tip-off from his close friend, Prince Kawashima. It is thought that Emperor Tenmu's 'Yoshino Covenant' contained his wish that talented brothers like Prince Otsu would support Prince Kusakabe, who was to inherit the throne.
That things turned out this way so soon after his passing must have been a source of great regret for Tenmu as well.

While the truth of the matter is unknown, some hold the view that it may have been an incident triggered by the anxiety of Uno no Sarara, who doted on her son, Kusakabe. Those interested may wish to look into this.

The burial site in Yamato, the mountain where the sun sets

Now, about Mount Nijo. With the northern peak, Odake, at 517m and the southern peak, Medake, at 474m, it is by no means a high mountain, but it is a familiar landmark to locals as the boundary between the western part of Nara Prefecture and Osaka Prefecture.
It is said that 'Sanukite' (sanukite), which was used for stone tools in the past, can only be found in Sakaide City, Kagawa Prefecture, and this Mount Nijo.

In the land of Nara, there is a concept that contrasts Mount Miwa, the 'Mountain of the God where the sun rises' in the east, with Mount Nijo, the 'Mountain of the Pure Land where the sun sets' in the west.

O Shrine (Tawaramoto Town), which enshrines O no Yasumaro, the compiler of the Kojiki, is located on a straight line connecting Mount Miwa due east and Mount Nijo due west. It is an important site for sun worship, as it is a shrine where the sun rises from Mount Miwa and sets behind Mount Nijo on the spring and autumn equinoxes.

Even in the era when the capital was in Asuka, the mausoleums of emperors such as Bidatsu, Yomei, Suiko, and Kotoku were built not in Asuka, where the capital was located, but in the land behind Mount Nijo, across the western mountains.
Come to think of it, Prince Shotoku's tomb is also located in 'Taishi Town,' behind Mount Nijo when viewed from the Nara Basin.

In the Manyoshu, there is a famous poem by Princess Oku, who grieved for the death of her younger brother Otsu, in which she sings of Mount Nijo.

'As I am a person of this world, from tomorrow on, I will look at Mount Nijo as my younger brother.'

Although the Manyoshu is an anthology of poems rather than a history book, I believe there are parts of it that convey the truth without fabrication even more than the Kojiki or the Nihon Shoki.

Conclusion

While we can only speculate now about the circumstances that led Prince Otsu to commit suicide, it is truly a sad thing that the life of a young prince was cut short, despite Emperor Tenmu's wishes.

I folded my hands in prayer in front of the Toriyaguchi Kofun before heading home.

By the way, about a five-minute walk from the Toriyaguchi Kofun, there is a uniquely shaped structure called Kasado (Umbrella Hall).

It was built in 1674 by the district magistrate, Noriie Yoshihiro, together with the local farmers, to pray for the soul of their lord, Masakatsu Honda. There is a belief that if you pray at Kasado three times, you will be able to pass away peacefully without causing trouble for others, such as needing assistance with personal care due to a long illness, which is why many people visit.

Mt. Nijo is a wonderful place rich in nature.
If you have the chance, please pay it a visit.