Shingai Kofun

Shingai Kofun is a burial mound at 新改, 土佐山田町, 香美市, 高知県, Japan. It is one of the 新改古墳群 and the largest mound in that group, which is spread along the 新改川. The round mound measures 15 metres across and 5 metres high.

Its burial chamber is a large side-entered horizontal stone chamber. It is 9.4 metres long, comprising a 玄室 measuring 6.6 metres by 1.9 metres by 3 metres and a 羨道 measuring 2.8 metres by 1.6 metres by 1.8 metres. The 1854 安政南海地震 damaged the chamber: part of its ceiling fell and the left wall of the 玄室 was lost.

Finds from the chamber include ornaments made from 碧玉, glass and small beads, together with iron arrowheads, knives and a 大刀鍔. Horse equipment included gilt-bronze fittings, 雲珠, 杏葉, leather fittings and a bridle. 須恵器 was also found.

The mound is dated to around the beginning of the 7th century, in the TK209型式期, at the end of the Kofun period. It followed the earlier 伏原大塚古墳, an early leader's tomb associated with the earliest TK43型式期 phase in 高知平野. By the TK209型式期, the position of leading rulers had moved to 小蓮古墳, although 伏原大塚古墳 continued to receive later burials. The site has been a 香美市指定史跡 since 1964年（昭和39年）10月27日.

Shingai Kofun is a megalithic mound (tumulus with integral stones) in Kami, Japan. A typological estimate: 250 CE to 650 CE. No English Wikipedia article exists for it; the full text below is the Japanese article "新改古墳", shown in the original language.