山王金冠塚古墳

The mound stands on the west bank of the Hirose River, a former course of the Tone River, in the centre-south of Gunma Prefecture. It is keyhole-shaped, with the front part facing south-east, and is built in 2 tiers. Fukiishi (covering stones) and haniwa have been recorded on its surface. The mound is 52.25 metres long, the round rear part has a diameter of 32.3 metres, and the front part is 42 metres wide.

The burial facility is a horizontal-entrance stone chamber with a side passage on both sides (ryōsode type), built in the rear part and opening to the south-west. The entrance of the passage has been destroyed, so the whole is not known, but the burial chamber is 3.64 metres long and 2.42 metres wide. The chamber is made of cut blocks of hornblende andesite from Mount Haruna, worked on 5 faces apart from the back, and in places the blocks are fitted together by notching. The chamber has since been backfilled.

The objects recovered in 1915 were a gilt-bronze crown, a gilt-bronze large belt, a helmet with a ram-shaped projection, a spearhead, 4 silver rings, 5 gold rings, a harness fitting (unju) and a cross-shaped fitting (tsuji-kanagu). The excavation of 1981 added 7 iron arrowheads, a hemispherical ornamental fitting of copper covered with gold foil, and more than 110 iron plates from armour. Ornaments, weapons, armour and horse gear were also found among the grave goods.

The gilt-bronze crown is a fine piece with few parallels in Japan, and it is noted for suggesting a strong connection with Silla. The finds are held by the Tokyo National Museum in Taitō, Tokyo.