Yamato Tenjinyama-kofun Tumulus (a keyhole-shaped mound in the beginning of the early Kofun period [ (大和天神山古墳)

Yamato Tenjinyama-kofun Tumulus is a keyhole-shaped tumulus constructed in the beginning of the early Kofun period located in Yanagimoto-cho, Tenri City, Nara Prefecture.

Summary

This is a keyhole-shaped tumulus facing the north located to the west of front square part of the Andonyama-kofun Tumulus. In 1960, taking advantage of the prefectural road expansion work which happened to cut off a part of the back circular part of the tumulus, an urgent excavation and research was conducted.

The research proceeded as a tumulus in the premise of Izanaki-jinja Shrine. However, due to a policy that any person's name is not to be contained in the name of a tumulus, it was named Tenjinyama-kofun Tumulus taking the local name of the place. There are, however, tumuli with this particular name in various regions, so it was named by putting Yamato at the beginning of the name.

Location

Scale and shape

It is a 113-meter long keyhole-shaped mound located on a terrace and its front square part slightly expands like a dovetail, but the expanded length does not exceed the diameter of its back circular part. Neither fukiishi (stones covering a tumulus) nor haniwa (clay figures) were discovered. The terraces and a surrounding moat are unclear, which has been pointed out the possibility that it originally didn't have them.

Buried person

Although a detailed research was conducted on the central part of the wooden container, no traces of somebody's remains being buried was found.

Burial facilities and burial goods

A 6.1-meter long vertical stone chamber was detected almost in the center of its back circular part. At the central part of the stone chamber, there remains a present 2.6-meter long wooden board, of which the center is divided by a partition making the space a wooden chest of one meter and 0.5 meter on the inside.

The unique vertical stone chamber of this tumulus has a roof in Gassho style (an architect technique of stone-beamed roof combined to form a steep roof that resembles two hands together), that is, a roof sloping to both sides without any ceiling stone.

Inside the stone chamber, there was a large wooden container to be looking like a wooden coffin at a glance but better to be regarded as a Mokuhitsu (wooden chest) by a detailed study and about four kilograms of Shu (vermillion) was stored in it. In view of a large amount of vermillion obtained and used, it is considered that it has some relationship with eastern Seto Inland Sea, because Tatetsuki Kofun Tumulus which used three kilograms of vermillion is located in Kurashiki City, Okayama Prefecture.

The bottom board of this wooden chest is 2.6-meters long and 75-centimeters wide with its cross section showing loose U-shape. However, it is not a hollowed-out chest from a giant tree but a combination of three vertically long wooden boards. Therefore, the inside bottom is not horizontal but with curved upward on both ends.

Inside the wooden chest, 20 pieces of bronze mirrors were placed. The 20 pieces of Dokyo were placed around the wooden chest consecutively forming a rectangle, which is entirely different from such an arrangement of only one piece being placed in the center as frequently seen in the tumuli of the early Kofun period.

Furthermore, on the outside of Koguchiita (the cut end of a board), two pieces were found on the north side and one piece on the south side, which made the number of bronze mirrors detected 23 pieces in total.

The 20 pieces in the wooden chest categorically consist of five pieces of Hokakukiku-kyo Mirror (also known as TLV mirror; a bronze mirror of which a circular boss inset on a square panel is in the center), four of Naiko Kamon-kyo Mirror (a bronze mirror with patterns like a flower-petal), four of Gamontai Shinjukyo Mirror (Mirror with figures of deities and sacred animals), two of Shaen Henkei Shinju-kyo Mirror (a mirror variation with half raised edge and relief engraving of animals and gods), three of Jukei-kyo Mirror (an animal-shaped mirror) and two of Gazo-kyo Mirror (a mirror casted images on the back).

Niju Koen tsubo (double rim pot) (Furu I type) was excavated from the front square part.