Local Secret · Sakae

Iwaya Kofun 岩屋古墳

One of Japan's largest square burial mounds, a 7th-century tomb around 78 m on each side, rising out of the woods of Boso Fudoki no Oka beside Boso no Mura. Free and usually empty.

About

The Ryukakuji burial mound group is a cluster of more than a hundred kofun spread across the hills of Sakae, and Iwaya Kofun is its giant: a square-shaped mound of about 78 m per side, among the very largest square tombs in Japan, built in the 7th century for a powerful local clan. Stone chambers made of shell-rich local stone open on its southern face. Wooded paths link it with dozens of smaller round and keyhole mounds and the archaeology displays of Boso Fudoki no Oka, making it a striking, atmospheric walk that few overseas visitors know about.

Highlights

• Among the largest square kofun in Japan, about 78 m a side
• Stone burial chambers visible on the south face
• Part of a group of over 100 mounds
• Wooded walking paths next to Boso no Mura

Tips

• Free to walk the grounds; combine with Boso no Mura's ticketed areas
• Paths can be muddy after rain
• Ryukakuji temple with its Hakuho-era Buddha is a few minutes away by car

Open in Google Maps · Info checked 2026-10-09

Nearby

• Boso no MuraMuseum · 450 m away
• Sakatagaike ParkPark · 480 m away
• YamatonoyuOnsen & Sento · 670 m away
• Ryukakuji TempleTemple · 1.5 km away
• Jinbei ParkPark · 4.4 km away
• Aeon Mall NaritaMall & Department Store · 4.6 km away
• Akasaka Park (Narita New Town)Park · 4.7 km away
• Nakadai Sports ParkPark · 5.2 km away