This is the largest keyhole-shaped tomb in Japan, measuring approximately 486 meters in length, 249 meters in diameter, 35 meters in height for the back circular mound, 305 meters in width and 33 meters in height for the front mound.
Engishiki (the classical compendium of rules) named this tomb Mozu-no-mimihara-no-naka-no-misagi, and currently, the Imperial Household Agency has determined it to be the tomb of Emperor Nintoku, the 16th emperor, and is in charge of managing it.
The mound is three-tiered with tsukuridashi (a space for religious ceremonies) on either side of the narrowest part of the tomb, and surrounded by three moats.
The current outermost moat was re-dug in the Meiji Era. In the 5th year of the Meiji Era (1872), a rectangular stone coffin placed in a pit-style burial chamber was excavated from the front rectangular mound, and along with it, swords, fine armor, glass pots, dishes, etc. were discovered.
Also, the Sasenmonjyutaikyo (a mirror) and Tahoukantoutachi (a sword with animal engravings), among others, which are said to have been excavated from this tomb are currently in the collection of the Boston Museum of Arts in the United States.
In addition, there have been more than ten smaller tombs called Baicho discovered around the tomb.
There is an approximately 2.8 kilometer walkway encircling the tomb, which takes an hour to walk around.