Sakitama Kofun Cluster

The Sakitama Kofun Cluster is a group of burial mounds in the city of Gyōda, Saitama Prefecture, in the Kantō region of Japan. The area of Sakitama gave its name to modern Saitama Prefecture. The site was designated a National Historic Site in 1938 and upgraded to a Special National Historic Site in 2020. It consists of nine large kofun built in the 5th to 7th centuries AD, from the late Kofun period into the Asuka period, when building burial mounds was already out of fashion in western Japan.

Eight of the large mounds are keyhole-shaped, with one square end and one circular end when viewed from above, and one is a large round mound. The area formerly held 35 additional smaller round kofun and one square one, all now destroyed by urban encroachment and land development. A survey in 1935 recorded 11 keyhole-shaped and 11 round mounds.

A chronicle records that in 534 AD Emperor Ankan appointed Nao Kasahara to a post in Musashi Province after he won a succession battle, and that a keyhole-shaped tomb miraculously appeared overnight at Kasahara, indicating the favour of the Yamato kingdom. This has led to a theory that the provincial administration was originally in this area, although the ruins of a provincial capital have been found in southern Musashi. In any event, the tumuli date from the end of the 5th century to the 7th century AD. They were known in the Edo period and commented on in local histories.

The Shōgunyama Kofun was excavated in 1893. Maintenance of the mounds began in 1966, and in 1968 the Inariyama Kofun was excavated, revealing a gold-inlaid iron sword, the Inariyama Sword. The area was developed into the Sakitama Kofun Park, where a number of traditional farm houses were moved for preservation, and a prefectural museum was opened.

Kofun are the great burial mounds of ancient Japan, built mainly between the middle of the third century and the early seventh century CE, and the period takes its name from them. The most distinctive form is the keyhole shape, but there are also plain round, double-rectangle and square mounds. Saitama Prefecture and the city of Gyōda are promoting the site for inclusion as a UNESCO World Heritage Site.

The area of "Sakitama" is the area which gave its name to become modern Saitama Prefecture. The site now consists of eight large zenpō-kōen-fun (前方後円墳), which are shaped like a keyhole, having one square end and one circular end, when viewed from above, and one large circular-type (empun (円墳)) kofun. However, the area formerly included an additional 35 smaller circular-type kofun and one more square-type (hōfun (方墳)), all of which have now been destroyed by urban encroachment and land development.

According to the Nihon Shoki chronicle, in 534 AD, Emperor Ankan appointed Nao Kasahara as Kuni no miyatsuko after he won a succession battle in Musashi Province for that post, and miraculously a keyhole-shaped tomb appeared in Kasahara, Saitama Country (present-day Konosu, Saitama) overnight, indicating the favor of the Yamato kingdom. This has led to a theory that the Musashi Kokufu was originally in this location, although the ruins of a provincial capital have been found in southern Musashi in the city of Kokubunji, Tokyo. In any event, the tumuli in this area date from the end of the 5th century to the 7th century AD. The existence of these tumuli were known in the Edo period and were commented upon in local histories, such as the "Shinpen Musashi Fudoki".

In 1893, the Shōgunyama Kofun was excavated and in 1935 a survey of the area indicated that 11 keyhole-shaped and 11 circular-type mounds existed. In 1938, nine largest burial mounds were designated as national historic sites. Maintenance on these tumuli began in 1966, and in 1968, then Inariyama Kofun was excavated, revealing a gold-inlaid iron sword (the Inariyama Sword). The area was developed into the Sakitama Kofun Park (さきたま風土記の丘, Sakitama Fudoki no Oka), and in addition to the tumuli, a number of traditional minka farm houses were relocated to the historic park for preservation. A museum, the Saitama Prefectural Museum of the Sakitama Ancient Burial Mounds (埼玉県立さきたま史跡の博物館, Saitama Kenritsu Sakitama Shiseki no Hakubutsukan) was also opened.

Saitama Prefecture and the city of Gyōda are promoting the site for inclusion as a UNESCO World Heritage Site, as a preliminary step, the site's designation was changed from a National Heritage Site to a Special National Heritage Site in 2020.