The Miyake Odoi Residence Ruins are the remains of a medieval fortified residence in Miyake-cho, Masuda City, Shimane Prefecture. Together with the Nanao Castle Ruins, the site forms part of the nationally designated historic site known as the Masuda Clan Castle and Residence Sites.
The site was once the main base of the Masuda clan, one of the leading warrior families of Iwami Province. Unlike a mountain castle designed primarily for defense, Miyake Odoi served as a center for administration, residence, and everyday life. Its remains provide valuable insight into how medieval warrior families governed their territories and lived within fortified residences.
The Masuda clan established its base in Iwami toward the end of the Heian period (794–1185). During the Kenchū era of the late 12th century, the clan moved its base to Masuda-no-sho and gradually expanded its influence from this area.
The exact date when Miyake Odoi was first constructed is uncertain. One widely accepted theory is that it was developed by Masuda Kanemitsu during the Oan era (1368–1375), in the Nanboku-cho period.
The location was particularly advantageous because of the nearby Masuda River. The river provided opportunities for transportation and the movement of goods, while also supplying water for agriculture. These geographical advantages made the area important for both economic activity and political administration.
Miyake Odoi was therefore more than a residence. It functioned as a base from which the Masuda clan exercised authority over the surrounding region.
During the later Sengoku period, the political situation surrounding the Masuda clan became increasingly unstable. As tensions with Mori Motonari intensified, clan leader Masuda Fujikane moved his base to the more defensible Nanao Castle in the mountains.
After the Masuda clan submitted to the Mori family, Fujikane returned to Miyake Odoi, which once again served as the center of regional administration.
During the time of his son, Masuda Motoyoshi, Miyake Odoi underwent further large-scale improvements. However, following the Battle of Sekigahara in 1600, the Mori clan lost much of its territory, and the Masuda clan was transferred to Nagato Province. Miyake Odoi was subsequently abandoned.
The Miyake Odoi site covers approximately 190 meters from east to west and 110 meters from north to south. Its distinctive shape, with the eastern side projecting northward, is sometimes described as resembling a long boot.
This unusual layout is thought to have reflected the need to combine defensive strength with the practical requirements of a large residential and administrative complex.
Moats and earthen ramparts surrounded the residence, creating a substantial defensive system. The earthen ramparts along the eastern and western sides reached approximately 5 meters in height.
Outside these ramparts were box-shaped moats approximately 10 meters wide and 2 to 3 meters deep. On the northern side, archaeologists have identified an even wider moat and traces of a former river channel.
On the southern side, a branch of the Masuda River was incorporated into the defensive system, demonstrating how the builders made effective use of the natural landscape.
A gap in part of the southern rampart may have marked the location of the main entrance, known in Japanese castle terminology as a kuruwa-guchi or koguchi.
The combination of moats, ramparts, waterways, and controlled entrances shows that Miyake Odoi was not simply a luxurious residence. It was a fortified political center capable of responding to the dangers of wartime.
Archaeological excavations have revealed numerous traces of buildings and artifacts within the Miyake Odoi site. These discoveries demonstrate that the complex was used continuously over a long period and was home to a variety of activities.
Among the discoveries are the remains of a wooden-framed well dating from the 13th century, foundation stones from buildings dating to the 16th century, a stone-lined well, and the remains of a blacksmithing workshop.
Large quantities of ceramics dating from the 12th through 16th centuries have also been excavated. These objects provide clues about everyday life, trade, dining, and the movement of goods during medieval Japan.
Together, the archaeological evidence shows that Miyake Odoi was not merely a center of government. It was a place where people lived, worked, produced goods, stored supplies, and conducted political affairs.
The layout of Miyake Odoi appears to have separated residential and administrative functions.
The western part of the site is thought to have contained the lord’s residence and gardens, forming a more private area for daily life. The eastern side is believed to have housed political facilities, storehouses, and workshops such as the blacksmithing area.
This division between private residential space and public administrative space provides an interesting glimpse into the lifestyle and organization of a medieval warrior lord’s residence.
Today, the Miyake Odoi site has been developed as Odoi Hiroba, a historical park where visitors can explore the remains in a peaceful setting.
The locations of excavated buildings are indicated with different colors, making it easier to understand the former layout of the complex. These visual aids allow visitors to imagine where residences, gardens, administrative facilities, storehouses, and workshops once stood.
Walking across the grounds provides a chance to experience the scale and structure of a medieval fortified residence rather than simply viewing individual archaeological objects in a museum.
Miyake Odoi survived major changes to the surrounding area in part because it was protected by Senko-ji Temple, founded during the Azuchi-Momoyama period (1568–1600). This helped preserve the historic landscape from large-scale urban development.
The site was designated a prefectural historic site during the 1960s. In 2004, it was designated a National Historic Site together with the Nanao Castle Ruins as part of the Masuda Clan Castle and Residence Sites.
Following severe flooding in 1983, Masuda City began conservation and improvement projects designed to balance the preservation of the historic site with public access and educational use.
Today, the site serves as a historical park and an important place for introducing the cultural heritage of the Masuda region.
One of the most interesting aspects of Miyake Odoi is its relationship with the nearby Nanao Castle.
Miyake Odoi functioned primarily as the Masuda clan’s residential and administrative center during peaceful times, while Nanao Castle provided a strongly fortified mountain refuge during periods of conflict.
Visiting both sites allows travelers to understand this contrast more clearly. One site reveals the everyday life and political administration of a medieval warrior family, while the other demonstrates how the same family used mountain terrain and defensive structures for protection.
The Miyake Odoi Residence Ruins offer a rare opportunity to experience the history of medieval Japan in a peaceful environment. Standing among the surviving earthworks and archaeological traces, visitors can imagine the buildings, gardens, workshops, and daily activities that once filled this fortified residence.
The site is particularly rewarding for travelers interested in Japanese castles and samurai history, but its spacious grounds and quiet surroundings also make it suitable for anyone who enjoys walking through historic landscapes.
By combining a visit to Miyake Odoi with the Nanao Castle Ruins, travelers can gain a deeper understanding of the Masuda clan and the political, military, and everyday life of medieval Iwami.
Miyake Odoi is more than an archaeological site. Its moats, earthen ramparts, building remains, wells, ceramics, and carefully planned layout reveal how a powerful medieval warrior family lived and governed its territory.
For visitors exploring Masuda City, walking through the historic grounds offers a chance to look beyond Japan’s famous castles and discover the lesser-known world of medieval fortified residences, regional government, samurai culture, and traditional Japanese landscapes.