Kohasu Kofun

Kohasu Kofun, also called Koren Kofun, is a Kofun period burial mound in the Okocho Kohasu neighborhood of the city of Nankoku, on the island of Shikoku, Japan. The tumulus was designated a Kochi Prefecture Historic Site in 1953.

It is located on the southern slope, approximately 20 meters above sea level, of the Hieyama Fault Line in western Nankoku City. Archaeological excavations were conducted in 1972, and a three-dimensional digital measurement of the stone burial chamber was performed in 2004.

The current shape of the tumulus is oval, measuring 28 meters north-south and 22 meters east-west, and 7.13 meters high. The original shape is uncertain, as part of the mound was leveled in later periods.

The burial chamber is a double-chambered, horizontal-entry stone chamber orientated to the southwest. It is believed to have been open since at least the Meiji era. The total length of the chamber, including the main chamber and passage, is 10.75 meters, making it the largest in Kochi Prefecture. It has a width of 1.95 meters near the back wall and 2.18 meters near the entrance, and a height of 2.85 meters near the back wall. It is connected by a 3.25 meter passage, and the floor is covered with split stones.

Excavations have yielded grave goods including gilded bronze hollow beads, gold rings, iron knives, iron arrowheads, chisels, horse fittings, and Sue ware pottery such as bowls, lids, straight-mouthed lids, and straight-mouthed jars.

Kofun are the great burial mounds of ancient Japan, built mainly between the middle of the third century and the early seventh century CE, and the period takes its name from them. The most distinctive form is the keyhole-shaped mound, with one square end and one round end seen from above, but there are also plain round mounds, double-rectangle mounds and square mounds.

The Kohasu Kofun is located on the southern slope (approximately 20 meters above sea level) of the Hieyama Fault Line in western Nankoku City. Archaeological excavations were conducted in 1972, and a three-dimensional digital measurement of the stone burial chamber was performed in 2004.

The current shape of the tumulus is oval. measuring 28 meters north-south and 22 meters east-west, and 7.13 meters high; however, the original shape of the kofun is uncertain, as part of it was leveled in later periods. The burial chamber is a double-chambered horizontal-entry stone burial chamber orientated to the southwest . It is believed to have been open since at least the Meiji era. The total length of the burial chamber, including the main chamber and passage, is 10.75 meters, making it the largest in Kōchi Prefecture. It has a width of 1.95 meters (near the back wall) and 2.18 meters (near the entrance), height 2.85 meters (near the back wall), and is connected by a 3.25 meter passage.The floor of the burial chamber is covered with split stones. Excavations have yielded grave goods including gilded bronze hollow beads, gold rings, iron knives, iron arrowheads, chisels, horse fittings, and Sue ware pottery (such as bowls, lids, straight-mouthed lids, and straight-mouthed jars).