This large circular tumulus was built on the edge of a hill on the north bank of the Oda River in the late 6th century. The mound boasts an imposing scale, measuring approximately 54 meters in diameter and 7 meters in height. The horizontal stone chamber, consisting of the main chamber and antechamber, is 19.1 meters long, making it one of the largest in the prefecture. The ceiling is made of four megaliths, the inner wall is made of a single block of rock, and three combination stone coffins are placed inside. The burial goods (swords, horse equipment, jewels, etc.) that bear witness to the power of Kibi during the late Kofun period are also known, and the site is preserved as a nationally designated historic site.

The stone chamber is locked with an iron fence, but the sarcophagus can be seen through the gaps. Those wishing to enter for study or photography must apply in advance (application to the Cultural Properties Protection Division).

Nestled in a tranquil bamboo forest, walking around the tumulus allows you to truly appreciate the imposing entrance to the stone chamber.

[Trivia]
- Yanada Otsuka Kofun is one of the "Three Largest Megalithic Tombs of Okayama Prefecture," along with Koumorizuka in Soja City and Musa Otsuka in Okayama City. Its stone chamber is one of the largest in the prefecture.

The designated parking lot is the "Yanada Otsuka Kofun Parking Lot" along Prefectural Route 54. It is about a 100m walk from the parking lot.