Susoezoana Kofun, Ancient burial mound in Ishikawa, Japan

Susoezoana Kofun is a square burial mound on a hill on Notojima island in Nanao Bay, about 20 metres on each side and 4.5 metres high. It contains two lateral stone chambers with passages roughly seven metres long, built from andesite slabs quarried on the island. The eastern chamber is T-shaped and the western one inverted L-shaped; both ceilings use corbelled stones to form a dome, a Goguryeo-style construction rare in Japan.

Susoezoana Kofun was built in the mid-7th century, when mound building had largely ceased elsewhere in Japan. Its two Goguryeo-style stone chambers, unusual for Japanese tumuli, suggest continental influence from the northern Korean Peninsula. The chambers were open in antiquity; a 1953 excavation recovered fragments of a stone sarcophagus lid, iron straight swords, Sue and Haji ware. It was designated a National Historic Site in 1981, and the buried person remains unknown.

The name "Ezoana" links the tomb to the Ezo, a term used in old Japanese texts for people of the north. The two chambers are called the male chamber (east, T-shaped) and the female chamber (west, inverted L-shaped). Excavated Sue and Haji ware, iron sword fragments and a stone sarcophagus lid fragment are shown at the adjacent Ezoana History Center.

The tumulus sits on a hill about 80 meters above sea level on Notojima, and the site is reached by car: roughly 10 to 20 minutes from Wakura Onsen Station on the JR West Nanao Line. The adjacent Ezoana History Center displays finds from the 1953 excavation, including Sue and Haji ware shards and iron sword fragments. The L-shaped chamber has partly collapsed, so entry is not possible.

Unlike many other mounds across Japan, this structure has a square shape instead of the common keyhole form found elsewhere. This distinction makes it a notable example of the variety that existed in burial architecture during this early period.