Saturday, January 21, 2017

Katsunoo Castle -Combination of front fort, residence and mountain castle-

Katsunoo Castle

-Combination of front fort, residence and mountain castle-



Name: Katsunoo castle (Katsunoo-jo)
Place: Kawachi-cho Tosu city, Saga
Location: 33.40214629348212, 130.46411788146517
Type: Mountain Castle
Built: 16th century
Remaining remnants: Stone walls, clay walls and dry moats 

Brief History

Katsunoo castle (勝尾城) is located on and around Shiroyama mountain, a side peak of Kusenbu-yama mountain at the east edge of Seburi mountains which separates former Chikuzen province (north part of Fukuoka prefecture) and Hizen province (Saga prefecture).

Castle site is places at the bottleneck point in combination with Mino mountains where was the border of Chikugo province (south part of Fukuoka prefecture) and Hizen province, thus castle site was an important point at the border of three provinces.

Mid-size warlords of Kyushu island

In the latter half of 16th century, three strong powers it mean Otomo clan which was the warlord of Bungo province (Oita prefecture), Ryuzoji clan at Hizen province and Shimazu clan of Satsuma province (Kagoshima prefecture) fiercely fought and captured short-time hegemony in turn. Under such situation, local lords normally belonged to these strong powers, and sometimes changed their master to survive. 

During disturbances many local lords were attacked by strong lord and disappeared from history. But several local lords such as Akizuki clan or Tsukushi clan seized opportunity of the decline of former superpower and grew into large lords held several providences. They nominally belonged to superpowers but managed their territory by themselves, and built main base and branch castles around their territory. As a deterrence toward their master and other superpowers, the main base of these mid-size lords were sometimes greater than superpowers.

Origin of Katsunoo castle

Katunoo Castle originally might be built in 14th century when the army of Muromachi Shogunate and supporters of the South Court fiercely fought in the north part of Kyushu island, the later became the castle of Shibukawa clan, a relative of Muromachi Shogunate and was appointed as the general governor of Kyushu island. But Shibukawa clan was defeated by Shoni clan and Katsunoo castle was once held by Shoni clan.

Shoni clan was a traditional clan which was said as the descendant of Hidesato Fujiwara (?-?) who was an ancestor of the lords of Kyushu island such as Otomo clan, Ryuzoji clan or Tachibana clan. After the establishment of Kamakura Shogunate, Shoni clan was appointed as "Dazai Shoni", the vice minister of Dazaifu city used the name of their role as surname.

At the invasion of Chinese Yuan Dynasty and Korian Koryo empire in 1274 and 1281, as Dazaifu capital became the target of attack then Shoni clan faced this invasion as front commander. But being suffered severe damage, Shoni clan stroke back this attack along with samurais of Kyushu island, then grew into the governors of north half of Kyushu island.

Struggle of Shoni clan and Ouchi clan

After the fall of Kamakura Shogunate, Kyushu island became the place of long conflict between Muromachi Shogunate and South Court supporters. Shoni clan divided into both supporters and significantly lost their power, and Muromachi Shogunate sent their representative Sadayo Imagawa (1326-1420) to manage Kyusui island. The leader of Shoni clan was assassinated by Sadayo, and after the return of Sadayo, Ouchi clan which was the warlord of Suo and Nagato province (Yanaguchi prefecture) advanced into north part of Kyushu island in turn.

Shoni clan tried to recover deprived territories and fought against Ouchi clan. Sometimes they won but faced total counter attack, then many leaders of the Shoni clan died in the battle and Shoni clan had to move their main base from Chikuzen province to the south part of Hizen province. However, in 1497, large army of Ouchi clan assaulted Shoni clan, then the leader of Shoni clan killed himself and Shoni clan was once extinguished. At this time Tsukushi clan which was the retainer of Shoni clan changed to Ouchi army the achieved Katsunoo castle.

Seizure by Tsukushi clan

The origin of Tsukushi clan was unknown but might be hereditary retainer of Shoni clan. Shoni clan became the lord of Katsunoo castle supported escaped relative of Shoni clan for recovery. Shoni army sometimes broke Ouchi army under the support of Tsukushi clan and Ryuzoji clan, but the leader of Tsukushi clan was killed by Shoni clan blamed for former turn. Therefore, Tsukushi clan broke with Shoni clan and became an independent lord.

At first Tsukushi clan belonged to Ouchi clan and fought with Otomo clan, but after the ruin of Ouchi clan by the coup d'?tat of their important general Harukata Sue (1521-1555), Tsukushi clan belonged to Mouri clan which beat Sue clan at the battle of Itsukushima in 1555 and succeeded former Ouchi territory. 

But during fierce conflict of Otomo army and Mouri army, Otomo army became dominant in north part of Kyushu island then Tsukushi clan turned to Otomo clan. Under Otomo clan, Tsukushi clan held a vast territory around the border of Chikuzen, Chikugo and Hizen province, and expanded Katsunoo castle as their main base.

Structure of Katsunoo castle

Katsunoo castle is a huge castle complex spreads over 2 kilometer square around the valley of the tributary of Yasuro-gawa river, a tributary of Chikugo-gawa river, and surrounding mountains. The ruin consist of Katsunoo castle which was the main base at the mountain, Residence of Tsukushi clan at the hillside, ruins of the castle town spreads along the valley, and front forts such as Takatori castle, Tsuzura castle or Wakayama fort surrounded the valley. The size and construction of the ruin is equivalent to Ichijodani Palace (Fukui prefecture), a splendid ruin of the main base of strong warlord Asakura clan.

Katsunoo castle, the main mountain castle, spread over the peak of Shiroyama mountain and three ridges prolonged toward southeast, south and southwest. Central area of the castle is about 60 meter long and 40 meter wide, which is partially decorated by stone walls. At just below of central area, a long and narrow terrace over 100 meter long spread from north to south, having huge rock as watching point at south edge and vertical and horizontal dry moats at north half.

At the east of central area, secondary area spreads along the ridge prolonged toward southeast. A large terrace of 80 meter long and 30 meter wide held stone walls at north side slope  is built at the root of the edge, and along with the ridge line of clay wall and dry moat spreads over 200 meter. At the end of this line, a masugata style gate protected by stone walls is built.

The ridge toward southward is the main route from hillside residence, and a splendid main gate of the castle is built utilizing small valley. Utilizing the slope of the valley huge clay wall covered by stone walls is built, and at the center there is a ruin of the gate might be protected by barrack gate. The southwest ward ridge might be the backside entrance, and is also protected by line of stone walls built at several part. Total size of mountain castle area is 400 meter long and 300 meter long, and extraordinary one at the area.

Ruins at hillside valley

Ruin of hillside residence of Tsukushi clan consist of upper terrace of about 100 meter long square now used as the ground of shrine, and lower one of same size became car parking. Most part of ruin was lost but there slightly remains broken structure of front side stone wall and masugata style gate, which reminds former prosperity of Tsukushi clan. 

Going down from the residence of Tsukushi clan along with the valley, there was a ruin of Tsuzura castle on a low hill at the entrance of the valley. The main body of Tsuzura castle is a simple oblong shaped terrace of 80 meter long and 40 meter wide, wholly surrounded by stone walls and dry moats. 

As Tsuzura castle is built on a low hill, two layered deep dry moat is built at whole part of south slope of the hill toward outside, connected to dry moat which separated the entrance of the valley over 700 meter. Inside of these dry moats, there are many terraces partially have stone walls, which were used as a ground for the residence of retainers. Other than these castles and forts, there remain many terraces, clay walls and dry moats all over the valley, which shows the whole valley was a huge fortress.

Among rise and fall of strong powers

Otomo clan once seized most part of north half of Kyushu island, but significantly lost their power at the defeat of the battle of Mimikawa against Shimazu clan in 1578, and fell from the ruler of Kyushu island. At north half Ryuzoji clan drastically rose under Takanobu Ryuzoji (1529-1584) who was feared as the "bear of Hizen", and south half was seized by Shimazu clan. 

Under such situation Tsukushi clan once left Otomo clan belonged to Ryuzoji clan and fought with Otomo army, but being defeated by two Dosetsu Tachibana (1513-1585) and Jyoun Takahashi (1549-1588), Tsukushi clan returned to Otomo clan. Around this time Ryuzoji clan had to cope with Shimazu clan, then Tsukushi clan was not attacked by Ryuzoji clan, and soon Takanobu Ryuzoji himself was died in the battle of Okiganawate against Shimazu clan in 1585.

After the death of Takanobu, Shimazu clan followed Ryuzoji clan then attacked remaining Otomo clan aiming at unification of Kyushu island. In 1586, Katsunoo castle was attacked by overwhelming Shimazu army and stood six days, but finally Tsukushi clan surrendered to Shimazu clan and the leader of Tsukushi clan was confiscated. 

Afterward of castle

Next Shimazu army fell Iwaya castle (Fukuoka prefecture) protected by Jyoun Takahashi but suffered severe damage, the hearing the landing of the army of central ruler Hideyoshi Toyotomi (1537-1598) at Kyushu island, Shimazu army once retreated from the area, Tsukushi clan recovered Katsunoo castle from Shimazu army.

Under Toyotomi government Tsukushi clan was approved as a small  feudal lord but was ordered to move to neighbor area and left Katsunoo castle. Katsunoo castle was abolished at this time along with neighbor castles. Tsukushi clan itself lost the position of feudal lord as a result of the battle of Sekigahara in 1600, but continued as a retainer of Edo Shogunate.

Now all building was lost but structure of the castle with line of stone walls well remain on and around the mountain. In addition to the dynamic exterior of mountain castle utilizing steep slopes, long line of dry moat also stoic attitude of Tsukushi clan to survive in the turbulent period. It takes time to visit whole part of the castle, but it is a valuable place to understand main base of warlord as a whole.


Nishitetsu Bus Kawachi-sen line from JR West Kagoshima-Honsen line Tosu station to Higashi-bashi bus stop at the entrance of the valley. 20 minutes drive from Kyushu Jidoshado Expressway Tosu interchange. 40 minutes walk from hillside residence to hilltop castle and caution for slippy climbing road.

Related Castles


Pictures (click to enlarge)

Tsuzura Castle


Residence of Tsukushi clan

Katsunoo Castle

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