1.直谷城跡の位置と地形(Location and Terrain of Naoya Castle Ruin)


The Naoya-jo Castle ruins in Yoshii-cho, Sasebo-city are located on a 30-meter-high sandstone residual hill rising from the fault plane of the Saza Fault,which stretches 15 kilometers from the mouth of the Saza-gawa River to the border between Yoshii-cho and Matsuura-city.Having many steep sandstone cliffs in this area makes Naoya-jo Castle a strong natural mountain fortress, and it has been said that the name of this region “Naoya” (straight valley) is originated from the terrain of this area.

旧石器時代から縄文時代にかけての遺跡として著名な「史跡 福井洞窟」の西南500メートルに位置し、山の地形を巧みに利用した典型的な中世の山城跡である。

This Naoya-jo Castle is located 500 meters southwest of the historic site calle “Fukui Cave”, which is a famous ruin dating back from the Paleolithic period to the Jomon period. It is a typical “yamajiro-ato”, a former site of a castle built on a mountain during the Middle Age period, taking full advantage of the mountain’s terrain strategically,


It was built close to the top of Dairi-yama Mountain, 167 meters above sea level.The Fukui-gawa River running at the foot of a mountain in the east was a natural moat and had a steep sandstone cliff that was used as a protective wall,making it a very solid castle.The top of the mountain was flattened to form a “Honmaru / Ichi no Kaku” (the main compound / First enclosure), 150 meters in length from east to west and 50 meters from north to south.


The lord of Naoya-jo Castle, the Shisa clan, was a member of the Matsuura Party, and developed a powerful clan dominating the territory of the northwest part of Kyushu Island. The Shisa clan is known for playing an active part vigorously in the Konan War (Mongol invasion attempts in 1281).


The clan developed into a ‘suigun’ (naval force) because of the geographical condition of facing the sea and of having few farmlands. They were also called'wako' (Japanese pirates) because they actively traded with the Ming Dynasty and Korea.


Also, the Shisa clan, the lord of Naoya-jo Castle, was originally based in Shisa,Matsuura, which was a convenient location for trading with the Ming Dynasty and Korea. Even after moving its headquarters to Naoya-jo Castle during the Warring States period, they had kept a close relationship with the Shisa region in Matsuura.

2.直谷城跡の特徴(Distinctive Features of Naoya Castle Ruin)


In the past, the three sample surveys were conducted at the Naoya-jo Castle ruins.

第二次調査の際に、一の郭跡に多数の柱穴が発見されたことから、建物は時代を経て何度か建て替えられたことが推測される。更に、発掘調査では約二千点の遺物が出土したが、その大半は中世の土器や陶 磁器で占められた。その他には、ガラス製品や、古銭、釘、硯、石鍋、るつぼなどが発見されている。

During the second sample survey, many holes of pillars were discovered at the ruin site of the first enclosure, so the buildings were assumingly rebuilt a few times throughout the ages.Furthermore, about 2,000 relics were discovered through the second archaeological excavation. Most of them, however, were the earthen vessels and ceramic wares of the Middle Age period. In addition, some glasswares, old coins, nails, inkstones and crucibles were also discovered.


The main purpose of the third excavation survey was to discover the location of the castellan’s residence in order to determine whether he normally lived in the second enclosure or usually lived at the foot of the mountain and stayed in the fortress only during the war. Unfortunately, none of the remains of the Middle Age period was discovered due to the limitation of the small-scale survey, but there is still a possibility that the lord’s residence existed at the foot of the mountain.


An access road was discovered in a place with a good view of the surrounding areas, but it is most likely for watch-keeping of the enemy. As a result of the third investigation, the total of 13 kinds of remnants was discovered, but none of the findings could determine the former site of the castellan’s residence.


This Naoya-jo Castle is one of the finest masterpieces of the Matsura clan, and the archeological remains are well-preserved even now.


There are two major passages to the castle. The front entrance is called “ootedo” (chaser’s road) and the rear one is called “karametedo” (trap road). Climbing up the front entrance road, there are two ascending trenches or pathways cut into a naturally-occurring slope. The depth of the trench is one meter now, but it was 2 to 3 meters then to prevent the invasion of the enemy.


There are three wells in the castle, but only one of them was used during a siege. The most important measures of the protection of this well were installed in “Ooteguruwa” (Entrance enclosure). It was made from quadruplet earthen walls and triple dry moats in between. The earthen walls are only one meter high now, but it has been assumed to be approximately 2 meters then. There are many areas called “Mushadamari” (Warrior mobilization area) in the fortress to counterattack the enemy. The connecting passages between Warrior mobilization areas are called “Mushabashiri” (Warrior passage).


The throwing-stone storage sites are established in the areas where seem to be weak in defense. The warriors threw the stones down at the enemies from the cliffs to counterattack.


There is a very interesting place in Naoya-jo Castle. It is a 28 meter high cliff, located in the north end. It’s called “Jogabana”, which means the nose of the castle, and it has a legend of “Himeotoshi” (Princess’ escape).


According to the Shisa story, the lord of the castle wanted to save at least the life of the little princess during the siege. They tried to hang the princess down from the cliff, but she fell to her death. Currently, there is a shrine which enshrines the princess.


This sheer cliff, however, hides a secret. In recent years, an escape route was discovered. It goes all the way down to the spot of 7 meter high from the bottom of the cliff where no one can claim up from the ground. From these facts, it is possible to think that the actual legend of the escape of princess is different from what has been told. The princess had possibly lost her life or killed by being attacked while running away instead of simply fell down from the cliff.

3.直谷城の歴史(History of Naoya-jo Castle)


There are many legends about the origin of Naoya-jo Castle, and the actual origin is not yet certain. The most dominant one is that the history of Naoya-jo Castle began during the Warring States period. It is known as a fact from the written documents that the Shisa clan in Matsuura moved their headquarters to the mountain fortress of Naoya-jo Castle during the Warring States period (1467-1568) because of the advantages of the defensive position. The fact that the excavations have revealed the largest number of relics from the Warring States period also supports its theory.


During the Warring States period, the countless battles were fought all over the nation, and Naoya-jo Castle was also the stages of the three battles. The biggest battle in the history of Naoya-jo Castle was fought against Matsura Takanobu, the lord of Hirado province, in the 6 th year of the Eiroku period (1563). Matsura Takanobu was displeased with Shisa Sumiharu, the lord of Naoya-jo Castle, from the begining. One of the retainers of Matsura Takanobu of Hirado lived in the territory of Shisa Sumiharu, and when he was killed by Sumiharu, Matsura Takanobu used the incident as an excuse to attack Naoya-jo Castle. As the result, Shisa Sumiharu lost the battle, and the territory of Shisa became a subject territory of the Matura clan of Hirado.


Matsuura Takanobu of Hirado took part in Toyotomi Hideyoshi’s conquest of Kyushu to unify the whole nation. He served Hideyoshi and became his feudal lord.


After that, Shisa Sumitaka, the lord of Naoya-jo Castle, joined Hideyoshi’s invasion of Korea along with Matsura Shigenobu, a child of Matsura Takanobu. Shisa Sumitaka lost his life in the battle in Korea, and the Shisa army went under the lordship of the Matsura clan of Hirado.


After the establishment of the Tokugawa Shogunate, Matsura Shigenobu became an early modern feudal lord, but Naoya-jo Castle of Hirado Province was abandoned by the “One Castle in One Province Order” issued by the Shogunate.

4.安徳天皇伝説(Legend of Emperor Antoku)


In 1185, the Battle of Dannoura between the Genji clan and the Heishi clan caused heavy casualties of the Samurai warriors. Among them was Emperor Antoku, a young female child born between Emperor Takakura and the daughter of Tairano Kiyomori, the lord of the Heishi clan. The Heishi clan was so prosperous one time that they even boasted and said, “This world exists for the Heishi clan”, and Emperor Antoku was the symbol of the Heishi clan.


Being defeated at the final battle, the grandmother of Emperor Antoku, the wife of Tairano Kiyomori, decided to commit suicide by jumping into the water with her granddaughter, the Emperor.


Emperor Antoku was almost 8 years old, and according to “The Tales of the Heike Clan”, she was described in a poem that she was ‘beautiful in appearance and even her surrounding was gloriously shining’. Before throwing herself into the water, the grandmother cleaned the inside of the boat, and placed the treasure sword around her waist. The grandmother and Emperor Antoku plunged into the water along with some other servants.


After that, mainly in Kinki, Shikoku, and Kyusyu areas, the legends that Emperor Antoku was actually alive arose one after another, and some people even claimed to be her descendants. It has been said that the girl who went into the water might have been a lookalike double of the emperor, and there are so many supposedly tombs of Emperor Antoku, but the truth remains a mystery.


The local people call Naoya-jo Castle in another name, “Dairi-jo”, which means the castle the Emperor lives. Along with the name of the place, “Dairi”, there are a lot of names of the places and the stories related to Emperor Antoku, and those legends becomes one of the elements of being attracted to have great interests in Naoya-jo Castle.


陣内城(松浦市志佐町)Jinnouchi Castle (Shisa-cho, Matsuura-city)

Jinnouchi Castle was originally renovated and built by Shisa Sumitsugu, the 11 th lord of the Shisa clan, during the Entoku period (1485 ― 1492) on the former site of Abe Muneto’s residence. After the Shisa clan moved its headquoters to Naoya-jo Castle during the Warring States period, Jinnouchi Castle supported Naoya-jo Castle as its “branch castle”.

加那城(かなじろ)(吉井町と松浦市の境界付近)Knajiro Castle (Near border area between Yoshii-cho and Matsuura-city)

There is an area named Kanajiro located in the middle of Naoya-jo Castle and Jinnouchi Castle. It is on the mountaintop, 321 meters above sea level, overlooking the both castles. Because of these geographical conditions, it is considered to be the former site of “Tsugi-shiro” (connecting castle), informing any unusual changes by the beacon fires.

世知原氏館(佐世保市世知原町)Sechibaru-shi-kan (Sechibaru-cho, Sasebo-city)

The Sechibaru clan was one of the senior vassals of the Shisa clan, the lord of Naoya-jo Castle. The town of Sechibaru still has the former site of the Sechibaru clan residence.

原城(南島原市)Hara-jo Castle(Minamishimabara-city)

Shisa Sumimasa, the 12th lord of Naotani-jo Castle, married his wife from the Arima clan, the lord of Hara-jo Castle in Shimabara, and after umimasa's death, his son became the 13th lord of Naoya-jo castle. Sumiyoshi’s son spent his childhood in Hara-jo Castle, which is the home of his other’s parents.

平戸城(平戸市)Hirado-jo Castle (Hirado-city)

Shisa Sumimoto, the 14th lord of Naoya-jo Castle, married a daughter of Matsura Takanobu of Hirado. Sumimoto deepened his relationship with the Matsura clan, the lord of Hirado-jo Castle, which is the parents’ home of his wife. Later, Naoya-jo Castle was absorbed to the Matsura clan of Hirado.



In recent years, the number of people visiting Naoya-jo Castle along with Fukui Cave has been increasing because of the increased interests in cotourism, the activities of volunteer groups, and the effects of the Internet, bringing the preferable results in the situation for utilizing the local cultural properties.


On the other hand, there are some issues and challenges.


First, the places with a great view, such as Himeotoshi cliff and the eastern tip of Higashi-yaguradai site, are extremely dangerous places being at the top-end of the cliffs. Therefore, it is necessary to ensure safety by installing the protective fences.


Secondly, the overgrown cedar trees under the cliffs are hiding the attractive appearances of a steady mountain fortress surrounded by extremely steep and sheer cliffs. The most distinctive feature of Nagoya-jo castle is now visually interrupted by the cedar trees, and this problem needs to be attended immediately to improve the image of Naoya-jo Castle.


Presently, the local volunteer organizations are regularly cutting the weeds and putting the guide plates and signboards of Naoya-jo Castle.


Furthermore, the historical experience tours combining Fukui Cave and Naoya-jo Castle are held every year, and recently the Fukui Cave Museum, displaying the 400 excavated articles, started its operation from April 28, 2021. Because the number of visitors to Fukui Cave is expected to increase even more from now on, the issues of the Naoya-jo Castle ruins are expected to be attended quickly.

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