---
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: 2026-08-27
change: "Rewrote the opening body section so that it no longer restates the page's own lead."
previous_hash: "68435558326c9e49e49c1f63a618a2e2c3285010c344ef9207d77e538c0502e8"
requester: internal
reason: "The section repeated the lead, so the first thing under the first heading was text the reader had already read in the search result."
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

Three moats ring it, and the mound holds something like 1.4 million cubic metres of earth; estimates of the labour run to more than a million man-days over fifteen years or more. Nobody may go in. The Imperial Household Agency administers it as a grave and has never permitted a full excavation, which is why the Nintoku attribution — made in the Edo period from a chronicle written centuries after the burial — cannot be tested against the mound's own date. It was inscribed as UNESCO World Heritage in 2019 with the rest of the Mozu-Furuichi group.

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.

**This page was corrected.** Rewrote the opening body section so that it no longer restates the page's own lead.

**Why.** The section repeated the lead, so the first thing under the first heading was text the reader had already read in the search result.

**Who asked.** The Media Division itself.