Ono Castle

From Jcastle.info



Ono castle is considered Japan's oldest castle. It was built to defend the cultural-political centre of Daizaifu, and provide refuge if Daizaifu fell under attack. According to the `Chronicles of Japan,` (Nihon Shoki), in the year 660, the Baekje (Kudara) kingdom on the Korean peninsula was besieged by the Tang-Silla alliance, and requested a relief force from the Yamato court in Japan. Crown Prince Naka no Ōe, later to become Emperor Tenji, and Empress Saimei ordered the dispatch of troops and ships, who ultimately sustained heavy casualties at the Battle of Baekgang in 663. Suffering from critical losses, and fearing retribution or invasion from the victorious Tang-Silla alliance, the Yamato court ordered the creation of Ono castle. This involved fortifying some eight kilometres of mountaintop and constructing and provisioning over 70 storehouses within the defenses. Other shore-based defenses and island-based signal towers were also constructed around this time, although the expected attack never came.

Visit Notes

Ono castle in effect comprises the entire mountain, with the various remains of stone walls, storehouses, ponds and gates scattered across it. It currently doubles as a nature park so there are many trails for hiking and enjoying nature - access to specific parts of the castle being inadequately sign-posted and at times confusing. The nearby Mizuki castle remains are usually considered a set with Ono castle, both erected in defense of Dazaifu, so these two sites may be of interest too.
profile and photos contributed by Kris

  • Ohno Dazaifu Gate
  • Hyakken Stone Wall
  • Stone wall near the Dazaifu Gate
  • Large Stone wall
  • Map

Castle Profile
English Name Ono Castle
Japanese Name 大野城
Founder Yamato Court
Year Founded 665
Castle Type Mountaintop
Castle Condition Ruins only
Designations Top 100 Castles, National Historic Site, Special Historic Site
Historical Period Pre Edo Period
Features stone walls
Visitor Information
Access By car: there is car parking at Shiouji-kenmin-no-mori. There is also a community bus from Daizaifu station, or Nishitetsu bus from Fukuoka Station.
Visitor Information Park facilities are open: April to September 9:00~6:00 October to March 9:00~5:00
Time Required Several hours: a lot of walking required between sites.
Website http://www.city.onojo.fukuoka.jp/edu/rekishi/iseki/onojoato.html
Location Ohno, Fukuoka Prefecture
Coordinates 33° 32' 2.80" N, 130° 31' 6.89" E
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Added to Jcastle 2013
Admin Year Visited Viewer Contributed
Admin Visits Viewer Donated

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53 months ago
Score 0++

Although the first kodai-yamajiro (Ancient Mountain Fortress) I visited was Yashima-no-Ki in Shikoku, most of the oldest and grandest sites being located in Kyushu visiting Chikuzen-Ōnojō was almost entirely outside my scope of experience. Most interestingly if I had visited mountain citadels in Korea, then I might've been more familiar with Ōnojō. The similarities between Ōnojō and old Korean sites are considerable, and this pertains to the history of the citadel mount. Long before the rise of the mighty samurai (from the Late Heian Period) who built medieval mountain fortresses, a still yet older culture of the Yamato built huge fortified mountain citadels by piling earth and stone into ramparts ringing mountains. Called Kodai-yamajiro, Ōnojō is typical and foremost amongst these. Essentially the mountain peaks were ringed with ramparts to protect structures within a depression between the fortified peaks. The ruins of some seventy of these structures, including their foundation stones, can be seen today. The remains of ramparts, some of them clad with piled-stone in a very ancient style, can be followed as it undulates across 8km of mountainous terrain. Of what remains of the ishigaki (stone-piled ramparts) at Ōnojō it is like no other I have seen at later Japanese castles, and sweeps up mountainsides and dips into ravines, creating a smooth parapet line which follows the natural contours of the elevation. The ishigaki is found in clusters here and there. We visited four areas with ishigaki, three of which were to the north of the castle ruins. These were the Hyakken'ishigaki, the Kitaishigaki, the koishigaki and, in the south, the Ōishigaki, this being the hardest to locate because we accidentally followed a ridge instead of the dorui (earthen embankment) at one point, taking a wrong turn and having to retrace our steps. Aside from the Hyakken'ishigaki, these stone-pilings seemingly were built at points between mountainsides where streams flowed through. The Hyakken'ishigaki, that designation referring to its great length, is quite different, starting at the base of a slope, surging up it and then along the top of a mountain ridge. It is part of one of two inner ramparts which created separately enclosed areas in both the north and south of the citadel.

Whilst the circular route following ramparts which bob up and down across the mountain's peaks and ridges can probably be walked in a few hours, to inspect everything at Ōnojō would likely take a whole day. Our route took us to (尾花) an area in the south where the remains of azakura (storehouses) can be seen. Then we (myself and Kyushu-based history blogger, Stuart Iles) stopped at a central parking area before walking a circuitous route between the three northern ishigaki remnants mentioned above. Coming back down the mountain we had just enough time to go and find the Ōishigaki in the south. So we saw some major features this way but did not have the time to walk around the whole site or inspect all of the building remains or ishigaki segments around.

Stuart and I also saw the Mizuki, a long, plain-spanning embankment built at the foot of Mt. Ōno, and an unrelated Sengoku Period fortification, Iwayajō, which is built within the ruins of Ōnojō, which says a lot about the age and size of Ōnojō that it has the ruins of a smaller, more recent castle within it! Stuart had been to these sites before and I appreciate his taking me to them and showing me around. I learnt a lot! (Stuart's site: https://reki...n.com/about/)


Kodai-yamajiro is a broad term, which is why I apply it here as a catch-all, although Ōnojō can also be described as a Chōsen-shiki Yamajiro (Korean-style Mountain Fortress). Kodai-yamajiro are generally split between Chōsen-shiki Yamajiro and another group of sites, these verging upon the truly ancient, called Kōgoishi-shiki Yamajiro. The relation of the one to the other is not entirely clear and some scholars consider the Kōgoishi sites to predate the Chōsen sites. The question is whether the construction of Kodai-yamajiro date to the defeat of Baekje and the subsequent defense of Yamato in the 7th century, or whether there was an existing tradition of the construction of such structures prior. This is not a settled question. I will say that whilst all Kodai-yamajiro appear to date to the Asuka Period, the Japanese had been using large stones to line their monuments from the Kofun Period, but any link there is utterly conjectural. The extent of the involvement of Korean refugees and immigrants in the construction of sites like Ōnojō can be a thorny topic of discussion since it pertains to the identity of ancient Japanese and their relations with continental peoples.


Ōnojō was built in 665, likely by or under the guidance of the Baekje nobility who had fled Korea following their defeat at the hands of the Tang-Silla Coalition. The Yamato had dispatched troops and ships to aid the Baekje in their war and after suffering heavy losses at the Battle of Baekgang were forced to contend with the possibility of the invasion of Japan by the wrathful Tang. Ōnojō was the centrepiece of a network of fortifications surrounding Dazaifu, the political center of Kyushu (with other sites including Mizu-ki, Shōmizu-ki, Kiijō, Ashikisanjō, the Sekiya Dorui and Dazaifu's administrative palace itself). The anticipated attack never came, however, and, by degrees, Ōnojō was abandoned to nature. As an old citadel to retreat to in times of war, it likely also played a part in the 13th century Mongol invasions of Kyushu.


54 months ago
Score 0++
Chikuzen-Ohno Castle is the foremost of its kind and impossibly vast with fantastical, climbing, undulating, valley-spanning ishigaki in parts. KODAI YAMAJIRO - they're a thing! haha. Especially in Kyushu. Another example on this site is Yashima Castle.


86 months ago
Score 0++
92! Well done. That's quite a feat.


86 months ago
Score 0++
I visited Onojo on March 16, 2017, which was my 92nd stamp in my 100 Meijo book. It was cold and windy, but a nice HIKE to the top. Onojo is one of the more difficult castles to get to because the directions are poor and the climb long and steep. Even the people that gave me the stamp had no idea what the castle was. To get there, I caught the community bus at the JR Onojo Station (100 yen) which you get right at the East Exit parking lot (they depart about every 30 minutes), and got off at stop #18 (clearly marked on the bus monitor) which was the Sougoukoen Iriguchi stop that takes about 20 minutes. Once off the bus, go straight under the underpass and circle around the baseball fields to the Sougoutaikukan (sports complex building). You can get your 100 Meijo stamp there too. There are stairs to the right of the building that circle to the back where the trailhead to the top of the mountain begins. This is very steep and often is like a stairway for 1 km -- my FitBit told me that I had gone up 96 flights of stairs when I got to the top! It took about an hour up. This trail intersects the circular castle trail that is in the map that Kris posted. I am 67 years old and did the round trip in about 4 hours. The views from the top are really incredible and the trail hiking was great -- but there was not much related to a castle to see. I would probably rate this as 1 star for the castle, but lots of stars for the hike and view. To get back to Onojo Station I caught the community bus at the exact place I got off and paid another 100 yen.