Bronze mirror and iron sword found in Tomio Maruyama Kofun, the largest round burial mound in Japan Nara

A large, shield-like mirror with elaborate patterns and a long, wavy sword were found in the largest circular tumulus in Japan, located in Nara City.

Experts say that it will be a valuable resource for considering the high level of technology at the time and how ancient tombs were buried.

Mirrors and swords were found at the Tomio Maruyama Kofun in Nara City, which was built in the latter half of the 4th century and is the largest circular burial mound in Japan.

Since October last year, the Nara City Board of Education has excavated a burial facility on the edge of the burial mound, and found a bronze mirror and an iron sword in the clay that covered the coffin.

Among them, the mirror is about 60 cm long and 30 cm wide, and has the shape of a shield with a rounded top.

The front side is polished to reflect light, and the back side has images of gods and beasts arranged in a circle, as well as detailed patterns such as lines resembling the teeth of a saw. It was treated.

Also, in the center part, there was a protrusion to pass the string through.

This is the first time that a shield-shaped mirror has been found.

An iron sword with a wavy shape called a 'serpentine sword' was also unearthed at the same location in the burial mound.

The length of the sword is just over 2.30 meters, making it the oldest sword of its type found in Japan and the longest sword of the same era found in East Asia.

Shinya Fukunaga, a professor at Osaka University who is well versed in the Kofun period, commented on the discovery, saying, "The mirror in particular is thought to have been made in a workshop that possessed the most advanced technology of the time, and can be said to be the greatest piece of metalwork in the first half of the Kofun period. It can be interpreted as a sacred combination of the defense of a shield and the mystery of a mirror, and has the power to keep evil at bay. It may have been buried as a burial item," he said.

"Mirror shaped like a shield"

The mirror found this time is shaped like a shield. Why was it called a mirror instead of a shield?

According to the Nara City Board of Education and the Kashihara Archaeological Institute, which conducted the survey, when the front side of the mirror was carefully checked with a microscope, it was polished so that light could be reflected, and it was also polished from the edge to the center. It means that it was in the state of a convex mirror that is gently inflated.

In addition, the back side has a protrusion called “chū” (string) through which a string can be passed through*, and a circular pattern of gods and beasts, which is characteristic of mirrors from the same period. It was

Furthermore, the material of the plate was bronze, which was copper mixed with tin and lead.

Since these characteristics can also be seen in mirrors excavated from burial mounds dating from the same period, it was determined that the shield-like plate was made as a mirror.

According to experts, the shields and mirrors found in the burial mounds are thought to have been buried with the meaning of protecting the "Nakigara" from evil spirits. It means that you can also think that you did.

Seigo Wada, director of the Hyogo Prefectural Archaeological Museum, who is familiar with burial mounds, said, "It can be said that it is a very symbolic form of burials at that time. I was surprised because it was the first form, but I think it was made to appear." talking

*The bias of "string" is not "thread" but "gold".

What is a "serpentine sword"?

The "serpentine sword" found this time is an iron sword with a wavy shape. More than 80 examples have been found in Japan so far, but it is the oldest of this type, and it is the same sword found in East Asia. It means that it will be the longest sword of all time.

Naohiro Toyoshima, a professor at Nara University who is familiar with weapons from the Kofun period, said, "If you want to make a sword that long, you have to have a fairly large furnace, people, and tools. You need a lot of iron, so advanced technology is required. And production system is necessary.It can be said that it is the masterpiece of blacksmith technology at that time."

On top of that, Professor Toyoshima believes that the length of the sword and the special design of the wavy blade may have a strong ceremonial element.

Professor Toyoshima said, ``Since it's shaped like a sword, it can be considered a weapon, but it's hard to imagine that it would actually be used in war. He may have played a role in both rituals."

About Tomio Maruyama Burial Mound

The Tomio Maruyama Burial Mound, which was investigated this time, is a large, round-shaped burial mound located in the western part of Nara City, and is said to have been built in the latter half of the 4th century, the early Kofun period.

In 2017, the city of Nara carried out detailed laser surveys and found that the burial mound is the largest circular burial mound in Japan, with a diameter of around 110 meters.

The burial mound has a three-tiered structure, the surface is covered with stones, and it is believed that haniwa were placed around the mound.

In addition to the burial facilities located at the top of the burial mound, there were also burial facilities located at the northeastern end of the burial mound, in a square protruding part called tsukuridashi.

The mirror and sword this time were discovered in the clay covering the wooden coffin placed in this tsukuridashi.

What kind of person was buried in the burial mound?

What kind of person was buried in the burial mound with a shield-shaped mirror and a long sword?

Professor Shinya Fukunaga of Osaka University, who is well versed in the Kofun period, said that the ``aruji'' of the Tomio Maruyama burial mound that was investigated this time was a powerful ruling family that supported the Yamato sovereignty. I believe that he was a close confidant who served

The Tomio Maruyama Burial Mound, which was investigated this time, is said to have been built in the latter half of the 4th century. During this period, the royal tombs of the Yamato dynasty, which were originally located in the southeastern part of the Nara Basin, moved to the northern part of the basin where the tomb is located. Professor Fukunaga believes that the 'master' of this kofun was a person who was at the center of the Yamato sovereignty and was like a key minister who supported the sovereignty.

However, since the mirror and sword were found not in the burial facility at the top of the burial mound, but in a protruding part called "tsukuridashi" at the bottom of the mound, Professor Fukunaga believes that they were buried in the tsukuridashi. , He was like a confidant who supported the master of the burial mound, and I believe that the mirror and sword this time were given to him by the master.

On the other hand, Naohiro Toyoshima, a professor at Nara University who is familiar with the weapons and armor of the Kofun period, said that the long sword and the shield-shaped mirror that were found this time have the roles of both fighting tools and festival tools. It is believed that the person buried in the burial mound was a person who was in charge of both military affairs and rituals.

The mirror and sword found this time will be cleaned to remove dirt and rust, and will be treated for preservation, but it is not yet known when they will be released to the public.

On the other hand, the excavation site of the ancient tomb will be open to the public on the 28th and 29th of this month.