★ World Heritage Kita-ku, Sakai, Osaka Keyhole-shaped mound

Itasuke Kofun

Location	Kita-ku, Sakai, Osaka
Shape	Keyhole-shaped mound
Mound length	146 m
Period	Early 5th c.
Designation	National Historic Site
World Heritage	Mozu-Furuichi Kofun Group (UNESCO)

Overview

146m keyhole-shaped mound. Around 1955 the mound faced destruction by earth-removal for housing development, and a bridge for hauling soil was built across its moat; a citizens’ movement led by archaeologists secured its preservation, and Sakai City purchased the site. It was provisionally designated a historic site on 14 November 1955 and became a National Historic Site on 15 May 1956. Sakai City Museum regards it as a forerunner of site-preservation movements across Japan, and the bridge footings left in the moat are a relic of that episode. A haniwa modeled on a keel-fronted helmet (shokaku-tsuki kabuto), collected from the rear circle during the preservation campaign, is the symbol mark of Sakai City’s cultural property protection. The mound is also nationally known for its colony of wild tanuki (raccoon dogs). Constituent monument of the UNESCO World Heritage "Mozu-Furuichi Kofun Group" (2019).

Finds & research

Three-tier construction. In addition to fukiishi (facing stones) and cylindrical haniwa, a haniwa modeled on a keel-fronted helmet (shokaku-tsuki kabuto) was excavated from the round rear mound (the symbol mark of Sakai City cultural property protection). The rear circle stands 11.4m high according to the official World Heritage site and the Agency for Cultural Affairs, but 12.2m according to Sakai City, which gives 11.4m as the height of the front section. The broad, short front section is distinctive. Radar survey shows the burial facility uses no stone, pointing to a clay-encased wooden coffin, but it remains unexcavated. A colony of wild tanuki (raccoon dogs) inhabits the moat, making this well known as "the kofun where tanuki live."

Official status & archaeological view

Official status

Provisionally designated a historic site on 14 November 1955 and designated a National Historic Site on 15 May 1956; in 2014 it was integrated into the National Historic Site "Mozu Kofun Group," and Sakai City, its owner, preserves and maintains it.

Archaeological view

Occupant unknown. Sakai City dates it to the first half of the 5th century from the shape of the mound and its haniwa. It has a projection on the south side of the waist. According to the Agency for Cultural Affairs, ground-penetrating radar has shown that the burial facility uses no stone, so it is likely a clay enclosure holding a wooden coffin. Sakai City ranks it 8th in the group — a ranking that counts the now-destroyed Mozu Otsukayama Kofun.

Field notes

The moat retains water and is also known as a habitat for wild tanuki.

World Heritage guide featuring this kofunMozu-Furuichi World Heritage Kofun A Visitor's Guide to the 49 Tombs →

⛩ Open the interactive map 📍 Google Maps

Sources

堺市古墳データベース「いたすけ古墳」堺市いたすけ古墳（指定文化財紹介・1955年の保存運動と1956年指定）堺市史跡百舌鳥古墳群整備基本計画（第2期）令和7年3月（1955年11月14日仮指定・1956年5月15日指定）堺市博物館常設展示ガイド百舌鳥古墳群（保存運動の先駆け）百舌鳥・古市古墳群世界遺産公式サイト文化庁文化遺産オンライン（世界遺産構成資産解説）

Last updated: October 16, 2026
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