Kengoshizuka Kofun

An eight-sided tomb

This octagonal kofun (ancient burial mound) was built in the second half of the 7th century. It measures about 22 m between opposite sides and about 4.5 m high, and was built in three tiers. The earth was raised by pounding it firm in layers, a technique called hanchiku, and the outside was covered entirely with cut blocks of tuff.

The important thing is the octagonal shape. In this period, eight-sided mounds were used only for the tombs of emperors: the tomb of Emperor Tenji, the joint tomb of Emperor Tenmu and Empress Jitō, and Nakaoyama Kofun all take this form. Neither round nor square, the octagon is thought to have signified the tomb of one who ruled all eight directions of the realm.

A chamber for two

The burial chamber is a stone box with a side entrance, hollowed out of a huge block of tuff brought from Mt Nijō. A partition was left standing in the middle of the single hollowed-out stone, dividing it into two burial rooms.

In other words, it was made from the start to hold two people. Nothing was added later; the joint burial was decided at the design stage.

Inside were found fragments of a kyōcho-kan, a coffin made of cloth hardened with layers of lacquer, tortoiseshell-shaped fittings decorated with cloisonné, and parts of human bones. The kyōcho-kan was the highest grade of coffin, used in Japan at that time only for a very few people.

The discovery of 2010

An investigation in 2010 confirmed that the tomb is octagonal. At the same time, a new small kofun was found to the southeast of the mound.

The position of this tomb, named Koshitsuka Gomon Kofun, matched an account in the Nihon Shoki, Japan's oldest official chronicle: that Empress Saimei was buried together with her daughter Princess Hashihito, and that her granddaughter Princess Ōta was buried in front of their tomb.

A chamber built for two, an octagon reserved for emperors, and a small tomb found exactly where the chronicle places it. With all three together, the theory that Kengoshizuka is the tomb of Empress Saimei suddenly became the leading one.

At odds with the official designation

The tomb that the Imperial Household Agency designates as Empress Saimei's is not this one but Kurumagi Kennō Kofun in neighbouring Takatori Town. Officially, therefore, the occupant has not been confirmed.

The shape, the structure, the finds and the location all support the leading theory, yet the official designation has not changed. Gaps like this are not unusual in Japan's ancient history.

The return of the white slopes

The tomb was designated a National Historic Site in 1923. For a long time it was overgrown with scrub, and the shape of the mound could hardly be made out.

Following the 2010 investigation, restoration work began and was completed in March 2022. The slopes of stacked cut stone shine brightly in the sun and stand out strikingly among Asuka's green hills. You can sense how conspicuous this tomb must have been when it was built.

Visiting

About 25 minutes on foot from Kintetsu Asuka Station. The tomb stands on a hill, and from the top you can look out over the villages of Asuka. The site of Koshitsuka Gomon Kofun has also been laid out right next to it.

In the evening, when the western sun falls on it, the whiteness of the cut stone is even more striking.