Iwaki-Taira Castle (Fukushima Prefecture) Complete Guide | History, Highlights, and Access Details
Iwaki-Taira Castle (Iwaki-Taira-jo) is an early Edo period castle located in Taira, Iwaki City, Fukushima Prefecture. Also known as Ryuga-jo, Ryujo, and Iino-jo, it served as the administrative center of the Iwaki-Taira Domain for approximately 260 years, becoming the political and economic center of the region. Today, remnants such as stone walls and moats remain, making it an important historical site that conveys the history of Iwaki City.
Basic Information on Iwaki-Taira Castle
Location: Former castle ruins and surrounding area, Taira, Iwaki City, Fukushima Prefecture
Common Name/Alternate Name: Ryugajo, Ryujo, Iinojo
Castle Structure: Terraced flatland castle
Builder: Torii Tadamasa
Year of Construction: Construction started in Keicho 8 (1603), completed in Genna 1 (1615)
Year of Abandonment: Meiji 1 (1868)
Designated Cultural Property: Nurishi Yagura stone wall designated as a historical site by Iwaki City
Iwaki-Taira Castle was built by Torii Tadamasa, a hereditary daimyo of the Tokugawa shogunate, as an important base to keep Date Masamune of Sendai in check. Construction of Iwaki-Taira Castle began in 1603 (Keicho 8) and was completed in 1615 (Genna 1) after 12 years. It was a formidable castle with a main keep, second bailey, and third bailey.
Detailed History and Background of Iwaki-Taira Castle
The Iino-Taira Era Before the Castle’s Construction
Before Iwaki-Taira Castle was built, this area was called “Iino-Taira” and was the territory of the Iwaki clan during the Sengoku period. The Iwaki clan used Iino-Taira Castle as their residence, but because they sided with the Western Army in the Battle of Sekigahara in 1600 (Keicho 5), they were dispossessed of their domain after the war.
Construction by Torii Tadamasa
In 1602 (Keicho 7), Torii Tadamasa, who enjoyed the deep trust of Tokugawa Ieyasu, was granted a 100,000 koku domain and entered Iino-Taira. Torii Tadamasa was the second son of Torii Mototada and became the first lord of the Iwaki-Taira Domain. His father, Torii Mototada, is known as a loyal retainer of the Tokugawa family who died in the Battle of Fushimi Castle, a preliminary battle to the Battle of Sekigahara.
Tadamasa immediately began construction of a new castle after taking up his post. Construction began in 1603 (Keicho 8) and, after 12 years and at enormous expense, Iwaki-Taira Castle was completed in 1615 (Genna 1). At this time, the place name was also changed from “Iino-Taira” to “Iwaki-Taira.”
The purpose of the castle’s construction was to keep Date Masamune, the lord of the Sendai Domain to the north, in check. Date Masamune was a powerful daimyo with a domain exceeding 1 million koku and was considered a potential threat to the Tokugawa shogunate, making Iwaki-Taira Castle a crucial strategic location in the Tohoku region.
Successive Lords and Changes in Domain Administration
After Torii Tadamasa, the Iwaki-Taira Domain was governed by several daimyo families.
Torii Clan Era: Torii Tadamasa was transferred to the Yamagata Domain in 1624, and his rule lasted only 22 years.
Naito Clan Era: From 1643, the Naito clan took control of the Iwaki-Taira Domain with a 70,000 koku stipend, and ruled for approximately 220 years. As a hereditary daimyo, the Naito clan held important positions in the shogunate and strived to stabilize the domain’s administration.
During the Naito clan’s rule, Iwaki-Taira Castle underwent several renovations, and the castle town was also developed. Although Iwaki-Taira’s stipend was only 70,000 koku at the time, commerce flourished, and it prospered as one of the leading economic cities in the Tohoku region.
The Boshin War and the Fall of the Castle
During the turbulent Bakumatsu period, the Iwaki-Taira Domain initially joined the Ouetsu Reppan Alliance, but later submitted to the Meiji government. However, in 1868 (Keio 4/Meiji 1), remnants of the former shogunate army occupied Iwaki-Taira Castle.
In August of the same year, the Meiji government forces attacked Iwaki-Taira Castle, and after fierce fighting, the castle fell. Much of the castle was destroyed in this battle, and Iwaki-Taira Castle effectively became a ruined castle. After the Meiji Restoration, the castle was dismantled, and the castle site was sold to private individuals.
Castle Structure and Layout
Characteristics of a Terraced Flatland Castle
Iwaki-Taira Castle was built as a terraced flatland castle. A terraced layout is a structure where the second and third baileys are arranged in a stepped fashion around the main bailey, combining defensive and practical features.
Honmaru: The central area of the castle, where the lord’s residence and government offices were located. No keep was built in the Honmaru; instead, a three-story turret stood there.
Ninokuruwa: Located east of the Honmaru, this area housed the residences of senior retainers and important domain facilities.
Sannomaru: The outer perimeter of the castle, where the residences of retainers and merchant districts were located.
Defensive Structures
Iwaki-Taira Castle, despite being a flatland castle, possessed advanced defensive structures for its time.
Stone Walls: Stone walls built using techniques such as rough-hewn stonework and fitted stonework surrounded the castle. Some sections of these walls remain in good condition today, providing valuable historical insights into the castle construction techniques of the time.
Moat: A wide moat surrounded the castle, preventing enemy intrusion. The moat’s water was drawn from the nearby Natsui River.
Watchtowers: Several watchtowers were strategically placed within the castle grounds, with the Nushi-yagura (lacquerer’s watchtower) being a particularly important defensive point. The stone walls of the Nushi-yagura are still preserved today as a designated historical site of Iwaki City.
Current Remains and Highlights
Tangosawa Park (Main Enclosure Site)
The main enclosure site of Iwaki-Taira Castle is now developed as “Tangosawa Park.” The park contains scattered remains that retain the atmosphere of the time, making it a central point for exploring the castle ruins.
Main Enclosure Stone Walls: Part of the main enclosure’s stone walls have been restored and preserved within the park, allowing visitors to observe Edo period castle construction techniques up close. The stone walls were built using the Nozurazumi method, characterized by their powerful form utilizing natural stones.
Moat: Traces of the moat separating the main enclosure and the second enclosure remain as topographical features, providing clues to understanding the defensive structure of the time.
Nurishi Yagura Stone Wall (Iwaki City Designated Historic Site)
The stone wall of Nurishi Yagura is the best-preserved of the remains of Iwaki-Taira Castle and is designated as an Iwaki City Historic Site. This stone wall, standing quietly in a residential area, is approximately 5 meters high, giving a glimpse into the scale of the original turret.
The stonework is done using the “uchikomi-tsugi” method, and the technique of “ma-zume-ishi” (filling the gaps between stones) is evident. This technique is characteristic of early Edo period castle construction and makes this a historically valuable relic.
Remaining Stone Walls and Moats in the Surrounding Area
The castle grounds of Iwaki-Taira Castle extended over a wide area, and traces of the original stone walls and moats can still be found scattered throughout the residential area around Iwaki Station.
Stone Walls in Front of the Station: Within walking distance of the north exit of Iwaki Station, stone walls remain on the grounds of private homes and along the roads. These are thought to be the stone walls that formed the outer perimeter of the second and third baileys.
Traces of the Moat: Although currently filled in, the location of the moat can be estimated from the topography and road layout. In some areas, archaeological excavations have confirmed the remains of the moat.
Castle Site Development and Future Plans
Iwaki City is focusing on the preservation and utilization of the Iwaki-Taira Castle site, and in recent years, investigations and development of the remains have been progressing. At Tangosawa Park, explanatory signs and guideposts have been installed, creating an environment where visitors can easily understand the castle’s history.
Future plans include considering the restoration of the stone walls and the reconstruction of the moat, and in the future, the castle site park may be developed to more closely resemble its original appearance.
Geography and Location
Iwaki-Taira Castle was built in the central part of Iwaki City, in the southeastern part of Fukushima Prefecture, facing the Pacific Ocean. The area around the current Iwaki Station corresponds to the former castle grounds.
Topographical Characteristics
Although Iwaki-Taira Castle is a flatland castle, it was not built on completely flat ground, but on a plateau with a slight difference in elevation. This slightly elevated area was also known as “Monomigaoka” (Observation Hill) and was ideally situated for surveying the surrounding area.
The Natsui River flowed to the north of the castle, serving as a natural moat. The castle town extended to the south, making it a crucial transportation hub where several roads intersected.
Importance as a Transportation Hub
During the Edo period, Iwaki-Taira flourished as a post town on the Hamakaido (Rikuzen-Hamakaido) road. The Hamakaido was an important route connecting Edo (Tokyo) and Sendai, and Iwaki-Taira served as a transit point, with many travelers and goods passing through.
Due to this geographical advantage, Iwaki-Taira developed not only as a military base but also as a commercial city. Many merchant houses lined the castle town, making it one of the leading economic cities in the Tohoku region.
Sightseeing and Surrounding Spots
Attractions Around Iwaki Station
Iwaki Station: A major station on the JR Joban Line and the gateway to the Iwaki-Taira Castle ruins. There is a tourist information center in front of the station where you can obtain castle ruin maps and historical materials.
Iwaki City Museum of Art: Located within walking distance of the castle ruins, it features exhibits on local history and culture.
Shirakawa Amida-do: A Heian period Amida hall designated as a National Treasure, it is a representative cultural property of Iwaki City. It is about a 30-minute drive from the Iwaki-Taira Castle ruins.
Model Course for Castle Ruins Walking Tour
Estimated Time: Approximately 2 hours
Course: Iwaki Station North Exit → Tangosawa Park (Main Keep Ruins) → Nurishi Yagura Stone Wall → Surrounding Stone Walls → Iwaki Station
A recommended course is to start from Tangosawa Park and walk around the surrounding stone walls and moat remnants. The stone walls that suddenly appear in the middle of a residential area evoke a sense of historical romance.
Access Information
Access by Public Transportation
Train: Get off at Iwaki Station on the JR Joban Line. From the North Exit, it’s about a 10-minute walk to Tangosawa Park (the site of the former castle keep). The journey from Tokyo Station to Iwaki Station takes approximately 2 hours and 15 minutes by the Limited Express Hitachi.
Bus: While a city loop bus operates from Iwaki Station, the main ruins are within walking distance, making walking a more convenient option.
Access by Car
Joban Expressway: Approximately 10 minutes from Iwaki Chuo Interchange. From the interchange exit, head towards Iwaki Station via National Route 6.
Parking: There is no dedicated parking lot at Tangosawa Park, but there are several coin-operated parking lots nearby. Using the municipal parking lot in front of Iwaki Station is convenient.
Address (for navigation): Former Castle Ruins, Taira, Iwaki City, Fukushima Prefecture (Tangosawa Park)
Points to Note When Visiting
Visiting Hours: The park is open 24 hours, but we recommend visiting during daylight hours.
Estimated Time Required: Approximately 30 minutes for Tangosawa Park only; 1.5 to 2 hours for a walk including the surrounding stone walls.
Notes: Some of the stone walls are located within a residential area and may be close to private property. Please observe proper etiquette and be considerate of residents when visiting.
Fun Facts When Visiting Iwaki-Taira Castle
Origin of the Name “Ryugajo” (Dragon Castle)
There are several theories as to why Iwaki-Taira Castle came to be called “Ryugajo” (Dragon Castle). One theory suggests it’s because the castle’s layout resembled a reclining dragon, while another theory suggests it’s because a dragon god was enshrined as the castle’s guardian deity.
Reasons why a castle tower was not built
Iwaki-Taira Castle did not have a castle tower built. This was because the construction of new castle towers was restricted by the “One Castle Per Province” decree and the Buke Shohatto (Laws for Military Households) of 1615. Instead, a three-story turret was built, which effectively served the role of a castle tower.
Battles in the Boshin War
The Battle of Iwaki-Taira Castle during the Boshin War, though only lasting a few days, involved fierce urban warfare. Fighting took place not only within the castle but also in the surrounding town, resulting in the destruction of many buildings. This battle, known as the “Battle of Iwaki,” was a crucial phase in the Boshin War in the Tohoku region.
Summary
Iwaki-Taira Castle is an important castle built in the early Edo period as a key point for the Tokugawa shogunate’s control of the Tohoku region. After a tumultuous history that included 12 years of construction by Torii Tadamasa, 220 years of rule by the Naito clan, and its fall during the Boshin War, the remains of the castle, such as stone walls and moats, are now preserved as a place of relaxation for citizens.
When visiting Iwaki City in Fukushima Prefecture, why not explore the remnants of the Edo period by visiting Tangosawa Park and the stone walls and moats scattered throughout the residential area? Development is still underway, and it is expected to be transformed into an even more attractive historical park in the future.
Located within walking distance of Iwaki Station, the Iwaki-Taira Castle Ruins offer a tranquil environment for historical exploration. This historical site, which holds an important place in the history of Japanese castles, is a hidden gem in Fukushima Prefecture well worth a visit.
