---
node: daisen_kofun
type: event
slug: daisen_kofun
title: "Daisen Kofun"
lead: "Japan's largest burial mound — the keyhole-shaped Daisen Kofun in Sakai, Osaka, about 486 meters long — was built c. 5th century. The Imperial Household Agency designates it Emperor Nintoku's mausoleum, an attribution scholars debate."
published: 2026-07-09
updated: 2026-07-09
image_file: daisen_kofun.jpg
image_source: "https://commons.wikimedia.org/wiki/File:Daisen-ry%C5%8D%EF%BC%8FTomb_of_Emperor_Nintoku_(Nintoku_Tenn%C5%8D-ry%C5%8D_Kofun)_view_balloon_01.jpeg"
image_author: "Indiana jo"
image_license: "CC0"
---

## What happened

In the 5th century (c.), Japan's largest burial mound was built at Sakai in present-day Osaka: the keyhole-shaped Daisen Kofun, about 486 meters long and ringed by moats. The Imperial Household Agency designates it the mausoleum of Emperor Nintoku, an attribution scholars continue to debate.

By footprint it ranks among the largest tombs on earth, alongside Egypt's great pyramids and the mausoleum of the First Qin Emperor.

## Background

Building on this scale demanded enormous organized labor sustained over years — evidence of the power the Yamato polity could command.

## Consequences

The mound has never been scientifically excavated; the Imperial Household Agency restricts entry, though limited joint surveys have begun in recent years. As part of the Mozu-Furuichi kofun group it became UNESCO World Heritage in 2019. It remains the most visible monument of the age when the Yamato kings consolidated Japan.