Inarizuka-kofun Tumulus (稲荷塚古墳)

The Inarizuka-kofun Tumulus, located in Mogusa, Tama City, Tokyo Prefecture, is a burial mound built in the late Kofun period (the period of ancient burial mounds) (the first half of the seventh century).

It has been designated as an important cultural (historical) property of Tokyo.


In the Edo period, there was a temple called Shifuku-in on the east side of the Inarizuka-kofun Tumulus; however, due to the Haibutsu-kishaku (a movement to abolish Buddhism) such as the Shinbutsu-bunri-rei (a law to forbidden the fusion of Shinto and Buddhism) in the early years of the Meiji period, Koiji-inari Shrine was built on the hilltop. When the shrine was built, the topsoil of the burial mound was scraped away to level the mound and most of the stones used for the ceiling were also removed, which caused changes in the circumfrence. It is said that the stone chamber was disturbed by grave robbers and the burial items were stolen.

In November 1952, an archaeological excavation was conducted, initiated by the teachers at Tama Junior High School with the help of the engineering officials of the Tokyo National Museum and the students of Tama Junior High School. The following year (1953), it was designated as an important cultural property of Tokyo because although the stones used for the ceiling of the stone chamber were exposed at the time, the burial mound and the stone chamber remained and it was proved that the stone chamber has a structure called Dohari-fukushitsu-kozo (multiple rooms with a womb-like structure).

At the beginning, it was considered that the shape of the Inarizuka-kofun Tumulus was round. However, through the research conducted from the 1980's to the early 1990's, it was proved that it was an octagonal burial mound which had never been discovered in Eastern Japan.

It is estimated that it was constructed in the first half of the seventh century (the late Kofun period). Because the stone chamber was already disturbed by grave robbers, it is not known who was buried there.

Although the stone chamber used to be open to the public, it is currently backfilled to protect the chamber. Blocks of different colors are put on the topsoil so that the location, the shape, and the size of the chamber can be recognized.

Among the seventh-century burial mounds found in Tokyo, it is the next largest burial mound after the Kitaoya-kofun Tumulus located in Hachioji City. The relationship between the Kitaoya-kofun Tumulus and the group of tombs located around the Inarizuka-kofun Tumulus is not clear because there is some distance between them. However, they have many things in common, such as the structure of the stone chamber and the age of construction.

In a history museum in Parthenon Tama located near Tama-center Station, a model stone chamber of the Inarizuka-kofun Tumulus and a part of the floor taken from the stone chamber, etc are displayed, in addition to the panels that introduce the Inarizuka-kofun Tumulus.


The Inarizuka-kofun Tumulus, whose entire length is 38 meters, is surrounded by a ditch of two meters in width. The full length of the burial mound is 34 meters and it has a two-tier structure. It is thought that the height was approximately four meters; however, the height is reduced by about half because the the top part of the mound was scraped away to construct Koiji-inari Shrine.

Total length of the stone chamber is about 7.7 meters. It is Yokoana-shiki sekishitsu (a stone chamber with a laterally attached entrance corridor) with three rooms: Sendo-bu (a passageway leading to the "zenshitsu") (about 1.6 meters in length and 1.2 meters in width), zenshitsu (a small room adjoining the "genshitsu") (about 2.3 meters in length and 1.7 meters in width), and genshitsu (a room where coffins and the dead were laid) (about 3.8 meters in length and 3 meters in width). The stone chamber was constructed by pilling up the cut tuff stones. A monolithic stone, 1.6 meters in height and 1.2 meters in width, is used as the back wall of the genshitsu room. Between the genshitsu and the zenshitsu rooms, enormous stones, such as a stone gate post of 1.7 meters tall, are used. The walls of zenshitsu and genshitsu rooms are curved like the body of a samisen (a three-stringed instrument). The structure of the wall is called Dohari-fukushitsu-kozo and it was constructed using an elaborate construction technique. Judging from the structure of the burial mound, it is estimated that it was constructed by the Koreans who settled in Japan.

On the floor of the stone chamber, red powders called Bengal (iron oxide) were spread and the fist-size stones called Enreki (conglomerate) were scattered about.

It used to be considered that the octagonal burial mound was built as the mausoleum of the Emperor (such as the Emperor Tenchi, the Emperor Tenmu, and the Empress Jito) constructed after the mid-seventh century. This way of thinking toward an octagonal burial mound was changed due to the continuous discovery of the Isezuka-kofun Tumulus (located in Fujioka City, Gunma Prefecture), the Mitsuya-kofun Tumulus (located in Yoshioka-cho, Gunma Prefecture), and the Kyozuka-kofun Tumulus (located in Ichinomiya-cho, Higashi Yashiro County, Yamanashi Prefecture [present day Fuefuki City]) after the discovery of the Inarizuka-kofun Tumulus in the Eastern Japan. Only about fifteen octagonal burial mounds were discovered, although approximately 150,000 burial mounds were constructed in Japan.


In the Kanto region, including the Tama area, the period from the mid-sixth century to the mid-seventh century (until the Taika Reform) was a time when, in order to expand the sphere of influence in the mainland of Japan, the Yamato Regime fought battles with Mojin ("hairy people" which refers to natives of Ezo), who had influence in the Kanto region and northward, to conquer them or to prevent their strong resistance and attempted to mediate the power struggles among the regional clans. It is said that "Emishi," the last name of SOGA no Emishi, was named after the historical background.

According to the Nihonshoki (Chronicles of Japan), "in 534, Ogi, who had power over Minamimusashi region, attempted to kill Kasahara no Ataiomi, Kuninomiyatsuko (the local governor) of Musashi Province, with the help of Oguma who governed Kamitsuke Province in order to usurp the position of Kuninomiyatsuko from Kasahara no Ataiomi." "However, Kasahara no Ataiomi allied with the Yamato Court and defeated Ogi (Musashi-kuninomiyatsuko War)." "As a result, Kasahara no Ataiomi was formally recognized as Musashi Kokusoke (the local governor family) by the Yamato Court." "At that time, Kasahara no Ataiomi presented four places, "Yokonu," "Tachibana," "Tahi," and "Kurasu," as Miyake (a territory under direct rule from the Yamato Court) to the Yamato Court." It is thought that "Tahi" is present day Tama area in Tokyo Prefecture.

Yokonu: Yoshimi-cho, Hiki County, Saitama Prefecture

Tachibana: Kawasaki City and the northern part of Yokohama City in Kanagawa Prefecture

Tahi: Tama Area, Tokyo Prefecture

Kurasu: The southern part of Yokohama City, Kanagawa Prefecture

After the death of Prince Shotoku, SOGA no Umako, and the Empress Suiko, a power struggle intensified within the Yamato Court. After the struggle, the Soga clan exercised their power; however, due to their aggressive behavior, the resentment against the Soga clan was increasing among the imperial family and other regional clans. In 637, the Emishi revolted against the Yamato Court and refused to pay tribute, and the Yamato Court dispatched KAMITSUKENO no Katana to the place (around present-day Gunma Prefecture). However, the Emishi fought back fiercely. The Yamato Court ruled by the Okimi (Great King) faced to a serious situation which could have threatened its existence, but they could barely suppress the rebellion. In 643, SOGA no Iruka ruined the Jogu royal family including Prince Yamashiro no Oe who had a blood relationship with Prince Shotoku.

Later, the Soga regime ended when the Isshi Incident was over in 645 and the Taika Reform was initiated in 646. This affected the policy toward the Emishi and the battle line moved to the northeast in the mid-seventh century (the subjugation of Ezo). As a law of the Taika Reform, Hakusorei (the Taika funerary law) was legislated. After the law was enacted, the tombs which were made by clans and ordinary people other than the emperor became much smaller and more simplified than the tombs constructed before the law. This represents how the Yamato Court had an influence on the region. With the establishment of the Taika Reform, Miyake, which was the territories under direct rule from the Yamato Court, was also abolished.

Wada Kofungun Burial Mounds

There is a group of burial mounds called "Wada Kofungun" on both banks of Okuri-gawa River (a tributary of Tama-gawa River) which runs on the south side of Tama-gawa River. On the east side of Okuri-gawa River, there are the Inarizuka-kofun Tumulus, the Usuizuka-kofun Tumulus, the Koshinzuka-kufun Tumulus, and the Tsukappara Kofungun. On the west side of Okuri-gawa River, there are the Nakawada Oketsubogun (Nakawada tunnel tombs) and the Hino City Manzoindai Kofungun burial mounds. Most of them were built in the late Kofun period from the mid-sixth to the mid-seventh century. In addition to the burial mounds, many dwellings and earthenwares were found in the remains of the Kofun period. This is one of the largest burial mounds in Tokyo. However, many burial mounds lost the top parts because they were scraped away and leveled. The burial mounds which retain the original shapes are getting fewer. Since many surrounding areas remain to be investigated, it is highly possible that the number of burial mounds to be found will increase further in the future.

Usuizuka-kofun Tumulus

The Usuizuka-kofun Tumulus lies about 100 meters to the west from Inarizuka-kofun Tumulus. The Usuizuka-kofun Tumulus was constructed in the first half of the seventh century, the same century when the Inarizuka-kofun Tumulus was built. The stone chamber with a structure called the Dohari-fukushitsu-kozo was constructed using cut tuff stones. The size of the stone chamber is smaller than that of the Inarizuka-kofun Tumulus, but the structures are the same. The stone chamber is currently backfilled.

Koshinzuka-kofun Tumulus

Although the Koshinzuka-kofun Tumulus has not yet been investigated, it is estimated that it is a round burial mound with a diameter of 10 meters. Some river stones which seem to be a part of the stone chamber are exposed. On the top of the burial mound, Koshinto (Koshin tower) is enshrined.

Tsukappara Kofungun Burial Mounds

The Tsukappara Kofungun are a group of burial mounds constructed during the 100 years between the mid-sixth century and the mid-seventh century. According to the Shinpen Musashi Fudo Kiko (a topography of Musashi Province from 1804 to 1829) written in the late Edo period, "Although there were 40 - 50 burial mounds in the Genroku era, the number fell to 14 or 15." However, only 10 burial mounds have been found so far. They are round burial mounds with Yokoana-shiki sekishitsu created using river stones, from which many burial items were discovered.

Nakawada Oketsubogun (Nakawada tunnel tombs)
They are the largest tunnel tombs found in Tama Hillside, and 19 tunnel tombs were found there. The structures of the tunnel tombs are Hokei-tanshitsukei (rectangular single room), Dohari-fukushitsukei (multiple rooms with the womb-like structure), and Daikei-tanshitsukei (trapezoidal single room). The bones of about 10 people were also found. It is estimated that the tunnel tombs were built around the first half of the seventh century to the early eighth century. The burial items, such as swords, iron arrowheads, small swords, glass beads, Hajiki-hai (Haji pottery for sake cup), and Sueki-yokobin (oblong earthen bottles) were discovered.

Hino City Manzoindai Kofungun Burial Mounds
They are burial mounds with Yokoana-shiki sekishitsu constructed using river stones, and three burial mounds have been found. The first tomb has a room with Dohari-tanshitsu structure (single room with a womb-like structure), the second tomb has a room with Katasodesiki-tanshitsu structure, and the third tomb has a room with the Musodesiki-chohokei-tanshitsu structure. It is estimated that they were constructed around the fourth quarter of the sixth century (575 - 600). The age of construction and the structure of the stone chamber have similarities to the Tsukappara Kofungun.


Address: 1140 Mogusa, Tama City, Tokyo Prefecture
The occupant of the tomb: Unknown
The age of construction: The late Kofun period (the first half of the seventh century)
Shape: An octagonal burial mound
Size: About 38 meters in total length, about 4 meters in height (the current height is about half of the length), and the surrounding ditch of about 2 meters in width
Interior: The interior has the Yokoana-shiki sekishitsu, which was constructed of cut tuff stones, with the Sendo-bu passageway and the zenshitsu and genshitsu rooms, all which are located on the second tier.
Burial Items: Unknown (due to grave robbing in the early years of the Meiji period)
Transportation: Take a bus from the Keio Line Seiseki-sakuragaoka Station, get off at the bus stop "Ochikawa" and walk seven minutes.

[Original Japanese]