Nakatsu Castle Complete Guide | History and Highlights of Nakatsu Castle, One of Japan’s Three Great Water Castles Built by Kuroda Kanbei
Nakatsu Castle, located in Ninomachi, Nakatsu City, Oita Prefecture, is a famous castle whose construction began in 1588 (Tensho 16) by Kuroda Kanbei (Takayoshi, Josui) at the command of Toyotomi Hideyoshi and was completed by Hosokawa Tadaoki. Known as one of Japan’s three great water castles, it features a moata utilizing seawater and is also called “Ogi-jo” (Fan Castle) due to its fan-shaped layout. Currently, it is open to the public as the Okudaira Family Historical Museum and is a representative tourist spot in Nakatsu City.
History of Nakatsu Castle | From Construction to the Present
Construction by Kuroda Kanbei (Tensho Period)
In 1587 (Tensho 15), after Toyotomi Hideyoshi’s conquest of Kyushu, Kuroda Kanbei (Takayoshi) was granted 123,000 koku in 6 districts of Buzen Province. The following year, in 1588 (Tensho 16), Kanbei Kuroda began construction of a new castle at a strategic location at the mouth of the Yamakuni River (then known as the Takase River). This location, facing the Suo Sea, was a vital point for water transport and strategically important for governing the northern Kyushu region.
Kuroda Kanbei utilized the latest castle-building techniques of the time, designing Nakatsu Castle as a water castle that drew seawater into its moats. The stone walls built during this period are of extremely high cultural value as the oldest surviving stone walls of a modern castle in Kyushu. The fact that Nakatsu Castle’s stone walls remain in such good condition, while other castles built around the same period throughout Kyushu have been lost, makes them invaluable resources for understanding the castle-building techniques of that era.
The Hosokawa Era (Keicho Period)
After the Battle of Sekigahara in 1600, Kuroda Nagamasa, son of Kuroda Kanbei, was transferred to Fukuoka in Chikuzen Province. In his place, Hosokawa Tadaoki became the daimyo of Buzen Province with a domain of 399,000 koku. Hosokawa Tadaoki was known as a warrior excelling in both military and literary arts, and he dedicated himself to the expansion and completion of Nakatsu Castle.
The Hosokawa clan further expanded the stone walls built by the Kuroda clan, and the joint between the Kuroda and Hosokawa periods is still clearly visible in the upper level of the main keep’s stone walls. This joint is a valuable historical site that allows for a comparison of the differences in castle-building techniques between the two eras. Hosokawa Tadaoki was also deeply knowledgeable in tea ceremony and culture, and he developed Nakatsu Castle not merely as a military base, but also as a cultural center.
Until 1632 (Kanei 9), when Hosokawa Tadatoshi (son of Tadaoki) was transferred to the Kumamoto Domain in Higo Province, the Hosokawa family used Nakatsu Castle as their residence for approximately 30 years.
The Short Reign of the Ogasawara Family
After the Hosokawa family’s transfer, in 1632 (Kanei 9), Ogasawara Nagatsugu was appointed to the domain from Akashi in Harima Province with a stipend of 80,000 koku. However, the Ogasawara family’s rule over Nakatsu Domain did not last long, and in 1639 (Kanei 16), they were transferred to the Kokura Domain in Buzen Province. Although the Ogasawara family’s rule was short, lasting only about seven years, Nakatsu Castle continued to function as the political center of the Buzen region during this time.
The Okudaira Family’s Entry into the Domain and the End of the Edo Period (From the Kyoho Era Onward)
In 1717 (Kyoho 2), Okudaira Masanari was granted a 100,000 koku domain from Utsunomiya in Shimotsuke Province. For approximately 150 years, until the Meiji Restoration, the Okudaira family ruled Nakatsu Domain, with Nakatsu Castle as their residence. The Okudaira family was a prestigious family related to Tokugawa Ieyasu through marriage, and their lineage began with Okudaira Nobumasa, who distinguished himself in the Battle of Nagashino.
During the Okudaira era, Nakatsu Castle flourished along with the surrounding castle town. Fukuzawa Yukichi spent his childhood in Nakatsu during this period, and the castle town prospered in terms of learning and culture. Successive Okudaira lords strived for domain reform and industrial development, maintaining Nakatsu Domain as a stable domain.
The Meiji Restoration and the Satsuma Rebellion
After the Meiji Restoration, Nakatsu Castle was abandoned due to the abolition of the feudal domains and the establishment of prefectures. In 1871 (Meiji 4), the castle tower was demolished, and the Nakatsu Prefectural Office was established in the main enclosure. Later, during the Satsuma Rebellion of 1877 (Meiji 10), the castle suffered a tragedy when the palace within the castle grounds was destroyed by fire. This war resulted in the loss of many buildings that had remained since the Edo period.
Modern Nakatsu Castle | Reconstruction of the Castle Tower
In 1964 (Showa 39), the former feudal lord Okudaira family took the lead, and with donations from the citizens of Nakatsu, a replica castle tower was constructed. This tower is made of reinforced concrete, and the interior has been renovated to house the Okudaira Family Historical Museum, which displays valuable materials passed down through the Okudaira family and the history of Nakatsu.
Since 2011 (Heisei 23), under a new management system, Nakatsu Castle has taken on a new role as a symbol of tourism in Nakatsu City, implementing various events and projects. Even in the Reiwa era, new initiatives such as the “World’s Best Flower Castle” project continue. ## Structure of Nakatsu Castle | Characteristics as one of Japan’s Three Great Water Castles
Design as a Sea Castle (Water Castle)
The most distinctive feature of Nakatsu Castle is that it is a “sea castle” or “water castle” with a moat utilizing seawater. Along with Takamatsu Castle (Kagawa Prefecture) and Imabari Castle (Ehime Prefecture), it is counted as one of Japan’s three great water castles, and its unique structure natefascis many castle enthusiasts.
Facing the Suo Sea to the north and bordering the Nakatsu River (Yamaguni River) to the west, these served as natural moats. Artificial moats were dug on the east and south sides, with a double moat on the east and a triple moat on the south fortified the defenses. An earthen embankment called “Okakoi-yama” surrounded the outer moat, creating a multi-layered defensive structure.
Seawater was drawn into the moat through a sluice gate, and the water level of the moat fluctuated with the tides. At high tide, the moat is filled with seawater, and at low tide, the water level drops, creating a unique landscape not seen in other castles. This system was also effective defensively, as it made enemy incursions difficult by utilizing the ebb and flow of the tides.
Castle Design as a Fan-Shaped Castle
Nakatsu Castle is also known by the nickname “Fan Castle.” This name comes from the fact that the castle’s layout resembles the shape of an open fan. The design, with the main keep as the focal point and the second and third baileys spreading out in a fan shape, is a clever way to maximize defensive capabilities while efficiently utilizing the limited land.
This fan-shaped layout is a manifestation of Kuroda Kanbei’s strategic thinking, making the most of the castle’s location between the sea and a river. The castle town also developed along this fan-shaped structure, forming the basis of Nakatsu’s town layout.
Kyushu’s Oldest Early Modern Castle Stone Walls
The stone walls of Nakatsu Castle are the oldest existing stone walls of an early modern castle in Kyushu. The stone walls built by Kuroda Kanbei during the Tensho period were constructed using the then-latest technique of “nozurazumi” (rough stone masonry), showcasing a powerful appearance with natural stones used as they are.
On the upper level of the main keep’s stone walls, the joint between the Kuroda-era walls and the Hosokawa-era walls is clearly visible. This joint is valuable evidence of how castle-building technology evolved in just a few decades. The Kuroda-era walls use relatively small stones in the nozurazumi style, while the Hosokawa-era walls use larger stones and exhibit a higher degree of processing.
During restoration work carried out in the Heisei period, the stone walls were carefully restored with the aim of recreating the stone-laying techniques of the past. Reinforcement was out while respecting traditional construction methods to avoid compromising the cultural value, and the walls still maintain their original appearance well today.
Okudaira Family Historical Museum | Exhibits and Highlights
Museum Exhibit Structure
The current interior of Nakatsu Castle’s keep houses the Okudaira Family Historical Museum. The museum offers a comprehensive look at the history of Nakatsu, focusing on valuable materials passed down through the Okudaira family, the last lords of the domain.
The exhibits include the Okudaira family’s clothing, swords, military equipment, old maps, and historical documents, providing a glimpse into the life and culture of a daimyo family during the Edo period. In particular, because the Okudaira family held a special position as relatives of Tokugawa Ieyasu, many items bestowed upon them by the Shogun are also on display.
Materials Related to Kuroda Kanbei
The museum also features extensive materials related to Kuroda Kanbei (Josui), the builder of Nakatsu Castle. Known as a military strategist for Toyotomi Hideyoshi, Kanbei’s intellect and character have captivated many. The museum provides detailed information about Kanbei’s life, the circumstances of the castle’s construction, and the state of Nakatsu at the time.
The museum also functions as a Kuroda Kanbei Museum, displaying items related to Kanbei, as well as models and drawings that help understand his castle-building philosophy.
Views from the Castle Tower
From the top floor of the castle tower, you can enjoy a magnificent panoramic view of Nakatsu city and the Suo Sea. This unique view, characteristic of a castle facing the sea, allows you to see all the way to the horizon on a clear day. You can also observe the flow of the Nakatsu River (Yamaguni River) and the layout of the town castle from above, truly appreciating Nakatsu Castle’s excellent location.
The changing appearance of the moat due to the tides can also be observed from the castle tower, providing an excellent visual point to understand its characteristics as a water castle.
Events and New Initiatives
World’s Best Flower Castle Project
In recent years, a new project aiming to become the “World’s Best Flower Castle” has been underway at Nakatsu Castle. This initiative involves planting seasonal flowers within and around the castle grounds, creating a castle adorned with beautiful flowers throughout the four seasons. This concept of “Japan’s only flower castle” is attracting attention as a new attraction of Nakatsu Castle.
In spring, cherry blossoms bloom; in early summer, hydrangeas; and in autumn, colorful leaves adorn the castle, delighting visitors. It’s also becoming increasingly popular as a photo spot, with active sharing on social media.
Hina Matsuri Event and Projection Mapping
Every year during the Hina Matsuri (Girls’ Festival) season, an event is held in honor of Nakatsu Castle, known as a “castle of” success.” Magnificent Hina dolls are displayed inside the castle, and projection mapping is held at night, creating a fantastical atmosphere.
The projection mapping visually depicts the history and stories of Nakatsu Castle, offering a different perspective on the castle’s charm compared to the daytime. This initiative, which fuses local traditional culture with cutting-edge technology, attracts many tourists.
Golden Week Special Event
During Golden Week, Nakatsu City’s mascot characters, “Okkun” and “Kurokankun” (modeled after Kuroda Kanbei), are present at the castle to welcome visitors. This event is popular with families with children.
The Immortal Fukuzawa Project
Projects related to Fukuzawa Yukichi, a great figure born in Nakatsu City, are also being implemented. Efforts to pass on Nakatsu’s history and culture to future generations are continuously underway, including the unveiling of an elaborate model of Nakatsu Castle, estimated to be worth 600 million yen.
Nearby Attractions
Okudaira Shrine
Within the grounds of Nakatsu Castle is Okudaira Shrine, dedicated to the Okudaira clan, including Okudaira Nobumasa. Okudaira Nobumasa, who distinguished himself in the Battle of Nagashino, was a warrior who married Kamehime, the eldest daughter of Tokugawa Ieyasu, and his descendants became the lords of the Nakatsu Domain. Okudaira Shrine is a place where you can feel the deep connection between the Okudaira family and Nakatsu.
Fukuzawa Yukichi Former Residence and Memorial Museum
Within walking distance of Nakatsu Castle are the former residence and memorial museum of Fukuzawa Yukichi, known as the author of “An Encouragement of Learning.” Fukuzawa Yukichi spent his childhood and youth in Nakatsu, where he laid the foundation for his academic pursuits. Visiting Nakatsu Castle and Nakatsu Castle Town together will give you a deeper understanding of Nakatsu’s history.
Exploring Nakatsu Castle Town
The castle town surrounding Nakatsu Castle still retains its Edo-period layout. Areas with a historical atmosphere, such as samurai residences and temple districts, are scattered throughout, making it a pleasant place to stroll. The Nakatsu City Historical and Folk Museum is also nearby, offering more detailed information about Nakatsu’s history.
##Visitor Information
Basic Information
Location: Ninomachi Honmaru, Nakatsu City, Oita Prefecture
Opening Hours: 9:00 AM – 5:00 PM (Last entry at 4:30 PM)
Closed Days: Open year-round (However, temporary closures may occur)
Admission Fee: Approximately 1,000 yen for adults (junior high school students and older) (※Fees may change, so please check the official website for the latest information)
Inquiries: 0979-22-3651
Access
Train: Approximately 15 minutes on foot from Nakatsu Station on the JR Nippo Main Line
Car: Approximately 10 minutes from Nakatsu Interchange on the Higashi-Kyushu Expressway. There are several parking lots around the castle (some paid, some free).
Bus: City loop buses are available from Nakatsu Station.
Continued Top 100 Japanese Castles Stamp and Castle Seal
Nakatsu Castle is selected as one of the “Continued Top 100 Japanese Castles,” and the stamp can be obtained inside the Okudaira Family Historical Museum. Castle seals are also sold and are popular as souvenirs of castle tours. Please check the official website beforehand, as the availability of stamps and castle seals may change due to museum closures, etc.
Cultural Value of Nakatsu Castle
Nakatsu Castle is designated as a historical site by Oita Prefecture, and its cultural value is multifaceted.
Firstly, as the oldest early modern castle stone wall in Kyushu, it is a valuable relic that conveys the castle construction techniques of the Tensho period to the present day. fact that Nakatsu Castle’s stone wall remains in good condition, while other castles built around the same time in Kyushu have been lost, is extremely important for the study of Japanese castle history.
Secondly, the castle’s structure as a sea castle (water castle) can still be seen today. The moat, whose water level changes with the tides, is still functional and provides a valuable example of the castle-building philosophy of the time.
Thirdly, it has a history of being the residence of many prominent daimyo families, including the Kuroda, Hosokawa, Ogasawara, and Okudaira clans, and traces of each era remain layered throughout the castle. In particular, the joints in the stone walls of the Kuroda and Hosokawa clans are valuable historical documents that allow us to witness the technological advancements of just a few decades.
Summary | The Charm of Nakatsu Castle
Nakatsu Castle is a famous castle built by Kuroda Kanbei, a leading strategist of the Sengoku period, and completed by Hosokawa Tadaoki, a renowned general skilled in both military and literary arts. As one of Japan’s three great water castles, it boasts a unique structure utilizing seawater and an elegant layout befitting its beautiful nickname, Fan Castle.
The oldest stone walls of a modern castle in Kyushu are a valuable cultural asset that demonstrates the evolution of castle construction techniques, making it a must-see for history and castle enthusiasts. Currently, it houses the Okudaira Family Historical Museum, a facility where visitors can learn about the history of Nakatsu and the Okudaira family, with a rich collection of exhibits.
With new initiatives aiming to become the “world’s most beautiful flower castle,” and modern events such as projection mapping, it continues to evolve as a tourist spot where tradition and innovation harmonize.
By visiting Nakatsu Castle, you can experience the history of Nakatsu from the Sengoku period to the Edo period and into the present day, and fully appreciate the charm of this famous Kyushu castle that has lived in harmony with the sea. When you visit Oita Prefecture, be sure to visit Nakatsu Castle and see its history and beauty with your own eyes.
