Kōbōyama Kofun

The kofun is located at an altitude of 650 meters in the Nakayama neighborhood of southern Matsumoto city, on the northern end of a hill named "Kōbōyama", with axis of the tumulus aligned northwest with the ridge line of the hill. The tumulus has a total length of 66 meters, with a square rear portion 33 meters wide by four 4 meters high, and a square front portion 22 meters wide by 3.5 meters high. The presence of some fukiishi has been discovered, but there is no trace of any haniwa or a moat. The tomb is estimated to date from the middle of the 3rd century to the middle of the 4th century.

The tomb was excavated in 1974, during which time a rock-lined burial chamber orthogonal to the main axis of the ancient tomb was found. Its internal dimensions were 5.5 meters long by 1.3 meters wide and 0.9 meters high. It was unusual in that its inner walls and floor were made of stacked river stones instead of cut-and-dressed stone. In the center was the remnants of a box-shaped wooden sarcophagus. Grave goods included a Chinese-made bronze mirror, three iron swords, a copper sheet, 738 small glass balls, magatama, an iron cauldron, 24 iron spearheads, and a large jug with an S-shaped mouth and many pottery shards. Many of these artifacts are now on display at the Matsumoto Municipal Archaeological Museum.

The kofun and its surroundings have been planted with over 2000 Yoshino sakura trees, and are a popular flower-viewing spot within Matsumoto city. It is approximately 15 minutes on foot from Matsumoto Station.

• List of Historic Sites of Japan (Nagano)

Wikimedia Commons has media related to Koboyama Kofun.

• Matsumoto city official site (in Japanese)