Musashi Fuchu Kumano Jinja Kofun-Tumulus (武蔵府中熊野神社古墳)

Musashi Fuchu Kamano Jinja Kofun-Tumulus is a dome-shaped grave mound, located in Fuchu City, Tokyo (Tokyo Prefecture). It was designated as a national historical site on July 14, 2005.

The Tumulus's Discovery and Excavation History
As its appellation suggests, the tumulus is located on the precincts of Kumano-jinja Shrine in Fuchu City, north of its main hall. Long before its excavation people believed that a mound on the shrine's precincts was a tumulus. As local legend goes, it was possible to enter the stone chambers until the mound partly collapsed at the Great Kanto Earthquake. Nevertheless, it was not until recently that the mound was confirmed as a tumulus.

As tradition has it, Kumano-jinja Shrine which had been in a different place in Fuchu City was relocated to the present site in 1777. It seems therefore that the shrine is not directly related with the tumulus.

When a float used for the shrine's festivals was broken in 1990, it was decided to create a new one. At the same time it was also planned to rebuilt a shed for the new float. The plan resulted in building a larger shed by removing a part of the hillock on the shrine's precincts. The Fuchu City Board of Education, however, issued instructions for excavating and studying the remains prior to the construction of the shed. Research excavation prior to any construction work was mandatory for certain areas in Fuchu City which used to be the seat of the provincial office of Musashi Province. It applied to Kumano-jinja Shrine.

The excavation findings showed that the mound on the shrine's premises had been constructed by the stamped-earth technique called 'hanchiku.'
The mound contained a large amount of river stones. However, it was far away from Takakura burial mounds which had been long known. Around the site there was no tumulus whose mound was constructed by the hanchiku technique. Moreover there was no pre-modern document to suggest that the mound is a tumulus. For these reasons the mound was not regarded as a tumulus even after its excavation.

In 1994 the City of Fuchu planned to investigate Takakura burial mounds which are located southeast of Kumano-jinja Shrine using an underground radar device. In so doing the mound behind Kumano-jinja Shrine was selected as one of the investigation targets. As the result of the radar investigation, a large construction was confirmed to exist from the top of the mound to and along the southern side. It was highly likely that the mound was a tumulus.

The excavation findings showed that the mound on the shrine's premises had been constructed by the hanchiku (A method of making the core of a podium). In 1996, an article was published on the ancient tomb behind the shrine, which was described in "Musashino Soshi." "Musashino Soshi" mentions that 'an ancient tomb was discovered behind Kumano-jinja Shrine. The entrance of the tomb is made of big stones and clayey soil. The inside is divided into three chambers. The third chamber is as big as a six-mat room, and its surroundings and ceiling are all made of hewn-stone-shaped clayey soil which is built up like a bridge with two semicircular arches.
It contains two human skeletons around which rusty-nail-like objects are scattered.'
Such descriptions in the journal suggest that the author in fact portrayed the interior of the stone chambers of the tumulus.

In May 2003 the excavation of the mound in Kumano-jinja Shrine began. It was not long before the excavation confirmed that the mound was a tumulus. It further showed by the end of 2003 that the mound was a three-story dome-shaped tumulus. In 2004 the stone chambers and their surroundings were excavated.

Location of the Tumulus
Musashi Fuchu Kumano Jinja Tumulus was constructed in Tachikawa Terrace in Musashino Plateau that stretches north of Fuchu Terrace which is a fluvial terrace of Tama-gawa River. The tumulus is approximately 0.5 kilometers away from Fuchu Terrace and the area surrounding the tumulus is mostly flat. About 1.2 kilometers in the southeast of the tumulus there are Takakura burial mounds which are a cluster of round barrows in the late Kofun period. In some 0.4 kilometers south of the tumulus, there is also a cluster of small tumuli which likewise are round barrows inthe late Kofun period and which surround Mitakezuka. However, Musashi Fuchu Kumano Jinja Tumulus seems to have been built independently of the others as there is no tumulus nearby.

Having said this, however, there is Tenmondai Konai Kofun-Tumulus which is a dome-shaped tumulus, similar in form and internal structure to Musashi Fuchu Kumano Jinja Tumulus, in Mitaka City, some 7.5 kilometers east of the Musashi Fuchu Kumano Jinja Tumulus. As some scholars have pointed out, moreover, the tumulus's stone chambers are similar to the one in Kitaotani Kofun-Tumulus in Hachioji City, some 9 kilometers west of the Musashi Fuchu Kumano Jinja Tumulus.

The areas surrounding the tumulus have increasingly become residential and there are few vacant lots around.

Grave Mound
The tumulus is a three-story dome-shaped grave mound. The ground level is about 32 meters on a side and about 0.5 meters in height. The first level is about 23 meters on a side and some 2.2 meters in height. Each is square-shaped. The thrid level is some 16 meters in diameter and about 2.1 meters in height and it is round-shaped. It has been estimated to be about 5 meters high when it was completed. The grave mound is constructed by the hanchiku technique with which to stamp down the soil and gravel dug out from the surrounding area, as well as flaky chips of siltstone used to construct the stone chambers.

The ground level is lined with curbs of the same siltstone used for the stone chambers, and each curb measures 40 to 45 centimeters by 35 to 45 centimeters by 15 centimeters. The first and the second level are covered with oval-shaped river stones. While a covering stone in the first level measures about 15 centimetes by 10 centimetes, a covering stone in the second level is larger than that and measures approximately 40 centimetes by 25 centimetes. Thus, the second level of square stones is visually distinguished from the third level of round stones. The flat area in the second level is covered with river stones.

No surrounding moats have been discovered near the grave mound. However, two depressions with some 6 meters in width and over 2 meters in depth have been confirmed east and south of and slightly away from the tumulus itself. These findings suggest that a large surrounding moat with 90 meters on a side may exist.

The Main Part of the Tumulus
The main part of the tumulus is structured into multiple horizontal stone chambers. It has a vestibule shaped like the Japanese figure eight or an open-ended triangle in front of the grave. There are three chambers, front, back and burial, starting from the entrance. The chambers are located on the ground level of the mound. Before the stone chambers were constructed, soft soil near the surface was removed by digging a large with approximately 8 meters wide from east to west, about 13 meters long from north to south, and over 1.5 meters deep. Red clay and clayey soil of the Kanto district was alternately poured into the hole and stamped down. This process called 'horikomi chigyo' (digging ground work) was carried out as foundation work. The tumulus's foundation work is unique in its depth of 1.5 meters although it is occasionally observed in tumuli from the late to the end of the Kofun period.

The total length of the stone chambers is nearly 8.7 meters. While the front chamber is square, the back chamber is slightly round and the burial chamber is almost circular in shape.
Circular burial chambers, often found in tumuli in Musash, which were built at the end of the Kofun period, are called 'drum-shaped stone chambers.'
The stone chambers of the tumulus are made of extremely soft silt stones. Each stone was cut into cubes and carefully combined with its neighboring stones. Silt stones are exposed on the Fuchu terrace that belongs to the fluvial terrace of Tama-gawa River. They are easy to process as they are as soft as soil although they are fragile and easily susceptible to collapse. As "Musashino Sosho" mentions, the tumulus was open to the public and people could enter the burial chamber in the Meiji period. It seems to have caved in later.

At the back of the burial chamber a small hole with about 9 centimeters in diameter and some 26 centimeters in depth was detected. This is taken as the trace of the hole made by a pile driven to mark the axial line when the chamber was constructed. It suggests that the tumulus was systematically constructed.

The chamber's floor was covered with flat stones, 10 to 20 centimeters in diameter, which were carried from Tama-gawa River. Depending on their shape, some stones are cut off at the edge so that they can match with others to cover the entire floor.

On the back wall of the burial chamber a scribble of 'Four Soldiers of the First Infantry Regiment of the First Battalion' was found. This was probably written in the Meiji period when the stone chambers were open.

Excavated Articles
Most of the burial goods inside the tumulus seem to have been taken away as the tumulus was open during the Meiji period. Only the following articles were excavated: an iron chape inlaid with silver, four small knives (tozu), many iron nails and six glass balls. Very few burial goods were unearthed.

Ninety iron nails were found in the burial chamber and a bunch of 55 nails were discovered in the back chamber. Also 216 broken pieces of iron nails were unearthed. Iron nails appear to have been used to close wooden coffins. It is highly likely that after nails and other things used for the wooden coffins upon the first burial were put away in the back chamber, wooden coffins for additional burials were placed in the burial chamber. Japanese cypress which seems to have been a part of a wooden coffin is attached to some iron nails. Silk is also attached to a tiny fraction of nails. Based on these points, some scholars have suggested that the dead persons were placed in the wooden coffins covered with silk cloth before they were buried.

The iron chape inlaid with silver, which was found in the burial chamber, is one of the most noteworthy articles unearthed. The iron chape, which is a metal fitting attached to the edge of a sheath, is decorated with beautiful silver inlays with the 'Shichiyomon' pattern, which was also used for Fuhonsen coins. It is an unprecedented article. It is assumed to have been made at an early stage of the late 7th century based on its shape.

Three permanent teeth which appear to have belonged to the buried were found in the burial chamber. They belonged to a person at the beginning or the early stage of mature age.

Some 117 coins including Kanei Tsuho, Bunkyu Eiho, 1 sen, 10 sen, and 0.5 sen were found in the stone chambers although they have no direct relationship with the burial articles in the tumulus. There are stones piled like an altar at the back of the burial chamber, and a candle dish and a candlestand were excavated. This may suggest that the stone chambers were used for worship as the inner shrine of Kumano-jinja Shrine when they were open to the public. The unearthed coins are probably money offerings.

Characteristics of the Tumulus
One of the characteristics of the tumulus is a tomb with a dome-shaped mound on a square base. At present, tombs with a dome-shaped mound on a square base officially confirmed through research excavations amount to only five in Japan, including the tumulus under consideration, and are therefore very rare.

The tumulus is the largest of all the officially confirmed tombs with a dome-shaped mound on a square base. Judging from the presence of the paved stones, the construction of the drum-shaped stone chambers through the advanced stone-building technique, and the iron chape with silver inlays among the burial articles, we may assume that it was constructed by an important local power in Musashi Province who had a close connection with the progressive Kinai government. Drum-shaped stone chambers are commonly adopted in the larger tumuli in the Tama region at the end of the Kofun period. Similarly, this clearly suggests that Musashi Fuchu Kumano Jinja Tumulus was constructed by an important local power.

It is difficult to estimate when the tumulus was built since no earthenware were found in it
When comparing the stone chambers with those in the neighboring tumuli and considering the iron chape with silver inlays among the burial articles, it seems that the tumulus was built from the mid to the late 7th century. Considering the fact that additional burials have been identified, some estimate that the first burials were made in the mid 7th century and the additional burials in the late 7th century.

The construction period of the mid 7th century onwards gains significance in connection with the historical situation around the tumulus at the time of its building. Which is to say, around the time of its construction, Tosando Musashi-michi Road was built about 1 kilometer east of the tumulus. From the end of the 7th century to the early 8th century, Musashi Kokufu (provincial office of Musashi Province under the ritsuryo system) was established at the center of the present Fuchu City. For these reasons, there is a cogent theory that states that the buried in the tumulus were local powers who played an important part in establishing Musashi Kokufu in the present Fuchu City.

Musashi Fuchu Kumano Jinja Tumulus was designated as a national historical site on July 14, 2005 for the following reasons: it is a rare tomb with a dome-shaped mound on a square base in Japan; it is one of the largest tumuli built in the ancient Musashi Province; and it is archaeologically and sociologically valuable remains since Musashi Fokufu was established nearby immediately after its construction.

Preservation and Opening to the Public

At the time of writing, work was underway to preserve the tumulus and preparations were being made to ready it for cultural usage. It was surrounded by fences and the entire mound was covered with sheeting to protect the remains. The opening of the tumulus to the public was scheduled for when the maintenance was completed at the end of fiscal 2008.