SilkCode LibraryCastles of Japan
No. 086Kyushu & OkinawaFukuoka

Ono Castle

大野城

Ruins & historic sites

Ono Castle is an ancient mountain fortress enclosing the ridges of Mount Shioji. Earthworks, stone walls and warehouse foundations preserve its character, rather than a later-style keep.

A wall of large stones at Ono Castle
A wall of large stones at Ono CastlePhoto: Tast at Japanese Wikipedia · CC BY-SA 3.0 · Resized and converted to WebP. Cards crop the display.This photograph shows the site at the time it was taken. Check the notes and official sources for current restoration work and access.

Get to know the castle

Castle at a glance

Site & layout
Ancient Korean-style mountain fortress
Origins
665
Builders & patrons
The court’s defensive programme for Dazaifu
Other names
—
What remains today
Earthworks, stone walls, gate remains and warehouse foundations

THE STORY

The story behind the walls

After defeat at the Battle of Baekgang in 663, the court prepared defences against a possible invasion from the continent. Ono Castle was built on Mount Shioji in 665 as part of this programme. It protected the north of Dazaifu within a network also involving Mizuki and Kii Castle. Foundations inside the perimeter record groups of storehouses. The preserved site now spans Dazaifu, Umi and Onojo, with mountain paths linking its remains.

LAYOUT & ARCHITECTURE

Read the landscape and the buildings.

Earthen ramparts follow the ridges, while masonry closes valleys and other vulnerable points. Storehouses within the extensive perimeter supported the defensive system. Openings through Hyakken Stone Wall show the need to drain water while blocking a valley.

A CLOSER LOOK

Details worth a closer look.

01

Hyakken Stone Wall

A long wall closing a valley reveals the scale of this ancient fortress. Drainage openings illustrate the technical demands of defending a valley.

02

Zochoten foundation stones

Foundation stones mark a group of buildings interpreted as storehouses. The four-building arrangement shows the fortress’s provision for supplies.

03

Defences along the ridges

Earthen ramparts and stone walls follow the mountain terrain. Its date and layout differ greatly from later castles centred on a keep.

THROUGH THE YEARS

A short timeline

  1. 663

    Defeat at Baekgang prompts stronger defences.

  2. 664

    Mizuki is built to protect Dazaifu.

  3. 665

    Ono Castle is built on Mount Shioji.

BEFORE YOU GO

A note before you go.

The remains are scattered across the mountain. Choose a route with an official map and check weather and path conditions.

Official visitor information ↗Find it on a map ↗

Information checked: 27 September 2026

Sources & official information

Some official sources are available in Japanese only.

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