A keyhole mound lying in the eastern Sasayama basin in Tanba-Sasayama City. The Hyogo Prefectural Museum of Archaeology ranks it second in Hyogo by restored length and the largest among the San'indo provinces. Meiji-era drawings of its buried armory conjure a warrior king. Managed by the IHA as a reference site, the mound itself is off-limits, but the view across the water-filled moat is imposing.
Finds & research
The 1896 investigation found numerous swords and armor pieces in a pit-style stone chamber. Its chest-shaped sarcophagus remains unopened. A 2004 IHA survey also identified haniwa and Sue ware.
Official status & archaeological view
Official status
The IHA manages it as the Kumobe Mausoleum Reference Site; Tanba-Sasayama City lists the designation date as 30 March 1900.
Attribution (jitei): the Imperial Household Agency's determination of whose tomb it manages — separate from heritage designation.
Archaeological view
A keyhole mound 140m long as visible, or 158m when its submerged foot is reconstructed, with a shield-shaped moat and outer belt. It was built in the mid-5th century. Local volunteers investigated it in 1896, confirming a pit-style stone chamber, a chest-shaped sarcophagus, and many weapons and armor pieces. Drawings record the arrangement of the grave goods; removed objects are held by the Kyoto University Museum. The sarcophagus was never opened. Tanba-Sasayama City describes a chieftain of regional ruler rank as the usual interpretation, and also mentions a theory that the occupant was Tanba-no-Michinushi.
Field notes
As a mausoleum reference site, the mound is closed; view it from outside. The Hyogo Prefectural Museum of Archaeology notes that no parking is available nearby and displays a reconstruction of the chamber and coffin based on the excavation drawings.