Ubazuka Kofun

The Ubazuka Kofun is a burial mound of the late Kofun period, located in the Mimasako-cho Shimoinoue neighborhood of Fuefuki, Yamanashi, in the Tōkai region of Japan. It was designated a Yamanashi Prefecture Historic Site in 1965. It now lies within the grounds of a Buddhist temple, the Jigenzan Nanshō-in, and a statue of Kannon is enshrined inside the burial chamber.

The mound is a large circular tumulus built on the left bank of the Kanagawa alluvial fan in the southeastern part of the Kōfu Basin. It measures approximately 40 meters in diameter and ten meters in height, and it was surrounded by a moat. It contains a single-chambered horizontal stone burial chamber opening to the southwest.

The burial chamber measures 17.54 meters in length, making it the largest in Yamanashi Prefecture and one of the largest in eastern Japan. It was constructed of natural stones measuring 1-1.5 meters. The back wall is built in two layers, the lower with two pieces and the upper a single monolith. There are five ceiling stones in the burial chamber and four in the passage, one of them at the opening having collapsed. A square pillar stone, 0.9 meters wide and approximately two meters high, marks the boundary between chamber and passage.

One theory holds that the passage was once 5-6 meters longer than it is now, because large stones scattered through the grounds of Nanshō-in may be repurposed ceiling stones. The chamber has been open for centuries, and no grave goods have been found. The kofun is believed to have been built around the end of the 6th century. To the south lies the Ninomiya-Ubazuka site, a settlement site from the same period.

According to legend, the mound is called Ubazuka (Old Woman's Mound) because a mountain hag competed with a giant to build it. It is also called Onbazuka (Prince Shotoku's Mound), because his beloved horse collapsed and was buried there when he visited Kai Province.

The Ubazuka Kofun is a large enpun (円墳)-style circular tumulus constructed on the left bank of the Kanagawa alluvial fan in the southeastern part of the Kōfu Basin. It measures approximately 40 meters in diameter and ten meters in height and was surrounded by a moat. It contains a single-chambered horizontal stone burial chamber opening to the southwest. The burial chamber measures 17.54 meters in length, making it the largest in Yamanashi Prefecture and one of the largest in eastern Japan. It was constructed of natural stones measuring 1-1.5 meters; however the back wall is constructed in two layers, with the lower layer consisting of two pieces and the upper layer consisting of a single monolith, and there are five ceiling stones in the burial chamber and four in the passage (one at the opening has collapsed). The boundary between the burial chamber and the passage is demarcated by a square pillar stone measuring 0.9 meters wide and approximately two meters high.

There is a theory that the passage is 5-6 meters longer than at present, given the presence of large stones scattered throughout the grounds of Nanshō-in, which may have been repurposed ceiling stones. The burial chamber has been open for centuries, and no grave goods have been found.

The kofun is believed to have been constructed around the end of the 6th century during the late Kofun period. To the south lies the Ninomiya-Ubazuka site, a settlement site from the same period. According to legend, it is called "Ubazuka" (Old Woman's Mound) because a mountain hag competed with a giant to build it, and it is also called "Onbazuka" (Prince Shotoku's Mound) because his beloved horse collapsed and was buried there when he visited Kai Province.