Dome-shaped Mound on a Square Base (上円下方墳)
A dome-shaped mound on a square base is a type of tumuli that were constructed in the past in the Japanese Islands, and also a type of mausoleums of the imperial family in modern times.
Summary
It has two stages: The bottom stage is square shape and the upper stage is circular shape. The dome-shaped mound on a square base is quite unique that only five are confirmed.
The first tumulus confirmed as this style is the Ishi no Karato-kofun Tumulus (also known as the Kazahahi-kofun Tumulus [風灰古墳]).
(Nara City, Nara Prefecture and Kizu Town, Soraku County, Kyoto Prefecture; estimated to be constructed in the end of the seventh century or in the early eighth century)
The Tumulus was excavated and researched in 1973. The next was found in 1985 on the foot of Mt. Ashitaka in Numazu City, Shizuoka Prefecture. The tumulus was named as the Shimizu Yanagi Kita Tumulus No. 1 (estimated to be constructed in the early eighth century). The third is the Musashi Fuchu Kumano Jinja-kofun Tumulus found in 2003 (Fuchu City, Tokyo Prefecture; the middle to the end of the seventh century). The fourth is the Tenmondai Konai-kofun Tumulus (Mitaka City, Tokyo Prefecture; estimated to be constructed in the middle of the seventh century) investigated to confirm in 2007. The Tenmondai Konai-kofun Tumulus was excavated and researched in 1970; however, it was confirmed by reinvestigation in 2007 that it was a dome-shaped barrow on a square base. The fifth is the Nojikubo-kofun Tumulus (Shirakawa City, Fukushima Prefecture; the end of the seventh century to the early eighth century) found in 2008.
Also, the Miyazuka-kofun Tumulus in Kumagaya City, Saitama Prefecture and the Sannozuka-kofun Tumulus in Kawagoe City, Saitama Prefecture is said to be dome-shaped barrows on square bases according to a survey drawing of the tumuli. However, the type of tumuli is not confirmed by an excavation, so they remain undefined whether they are the dome-shaped barrows on square bases or not.
Dome-shaped barrows on square bases constructed in modern times
This type of mausoleums was adopted for mausoleums of the imperial family, such as the Fushimi Momoyama Mausoleum of Emperor Meiji, the Musashi Mausoleum of Emperor Taisho, and the Musashino Mausoleum of Emperor Showa.
Dome-shaped barrows on square bases in the broad sense
There is a theory that burial mounds whose bottom stage is square shape and upper is octagon shape are included in the dome-shaped barrow on a square base. Among this dome-shaped barrow on a square base in the broad sense, the Gobyono-kofun Tumulus of Emperor Tenchi is the most famous. Also, the Ishibutai-kofun Tumulus is pointed to a possibility that it was a dome-shaped barrow on a square base.