Ishibutai-kofun Tumulus (a tumulus in the late Kofun period [Tumulus period] in Asuka Village) (石舞台古墳)

Ishibutai-kofun Tumulus is a tumulus in the late Kofun period located in Asuka Village, Nara Prefecture. It was designated as a special historical site by the Government on March 27, 1952.


It has been called Ishibutai (Stone Stage) due to the shape of its megalithic (granite) burial chamber which has been exposed from ancient times. The burial chamber is approximately 7.7-meter long, 3.5-meter wide and 4.7-meter high and the passageway to the burial chamber is approximately 11-meter long and 2.5-meter wide. There are drainage facilities inside the rock chamber. It is constructed by approximately 30 rocks, the total weight of which is estimated to be as heavy as 2,300 tons. The rocks were carried from the foot of Mt. Tonomine approximately three kilometers further up the Fuyuno-gawa River which flows by the side of the Kofun (tumulus).

Since the upper part of Hodo (covering soil) has been taken out, the shape of Kofun is presumed to have been a two-layer square, a dome-shaped mound on a square base or an octagonal base mound. Furthermore, it is said to have been a huge square tumulus with 51 meters square stylobate surrounded by a dry moat with stuck stones and additionally with an outer bank (approximately 83 meters from north to south and 81 meters from east to west).

There is a horizontal stone chamber depositing a kurinuki-sekkan (literally, a coffin hollowed out a stone) on the outside of the northwest corner of the outer bank and when it was discovered, it was presumed to be a Baicho (smaller mounds by a Kofun). In the ensuing researches, seven horizontal stone chambers were discovered also on the west side and their ground had been leveled. From the above and others, it is considered that for construction of the Ishibutai-kofun, Kofun located around it were scraped away and moved.

In 1933 and 1935, excavations and researches were conducted with Kosaku HAMADA of Kyoto University (at that time) and others taking the lead. However, almost all of the burial accessories had been stolen by grave robbers and only broken pieces of stone coffins were discovered. From 1954 to 1959, Kofun restoration and maintenance project was carried out. About this project, there is an anecdote that, for the excavation of the outer moat, the course of a Prefectural road running above it was changed.

The June 626 Section of "Nihonshoki" (Chronicles of Japan) describes as follows.
Oomi, a highest officer in national politics of the Yamato dynasty, died.'
Therefore, he was buried in Momohara grave.'
Oomi was the title of Umako.

A theory that the Ishibutai-kofun Tumulus was the tomb of SOGA no Umako is widely-accepted. Some say that it was a punishment on the Soga clan that Hodo (covering soil) was taken out and the grave was opened.

Masayoshi MIZUNO, a professor emeritus at Nara University preaches a theory that the Ishibutai-kofun Tumulus was the tomb of SOGA no Iname from the facts such as the kind of rocks, the era of construction.

In addition, the Kofun is open to public inspection during the day and visitors can get in under the stones.


Other than Ishibutai, it used to be locally called 'Ishifutoya' (a large stone), 'Ishibuta' (a stone lid) and so on. Regarding a legend that 'It came to be called Ishibutai (a stone stage) for the fact that a fox in the shape of woman danced on the Kofun,' Yoshinori ABOSHI who was born and brought up near the Kofun said he had never heard such a story and understood it was written in recent years.