Oshi Castle: A Sengoku and Edo-Period Castle in Japan
Site at a Glance
- Rating
- 3.9
- Popularity
- Medium
- Country
- Japan
- Primary era
- Early Modern
- External website
- Open
- Eras represented
- Medieval, Early Modern
- Civilizations
- Ashikaga shogunate, Tokugawa
- Site type
- Military
- Remains
- Castle
On this page12 sections
History
Foundation and Sengoku conflicts
Oshi Castle is a Japanese flatland castle in Gyoda, Japan, traditionally founded around 1478 or 1479 by the Narita family during the Sengoku period, an era of prolonged military rivalry among regional warlords. Narita Shoto and Akiyasu Narita established the castle after defeating the Oshi clan, which had been subordinate to the Ogigayatsu Uesugi. An older attribution to Narita Chikayasu was later revised through research into the Narita family genealogy.
The Ogigayatsu Uesugi attacked the new castle the following year, but Ota Dokan mediated a settlement that allowed the Narita family to retain the territory. After the 1546 Battle of Kawagoe, the Naritas resisted the expanding Odawara Hojo. A Hojo assault in 1553 was repelled. In 1559, the Narita family submitted to Uesugi Kenshin, a powerful warlord from Echigo. Castle lord Narita Nagayasu joined Kenshin’s attack on Odawara Castle in 1561, but later broke with him after Kenshin assumed the office of Kanto kanrei, a high-ranking position connected with supervising the Kanto region for the Ashikaga shogunate.
Uesugi Kenshin besieged Oshi Castle in 1574 and burned the castle town, yet the stronghold remained in Narita hands. Its position among marshes and watercourses helped the defenders withstand repeated pressure during the military struggles of the sixteenth century.
The siege of 1590
Oshi Castle faced its most famous attack during Toyotomi Hideyoshi’s 1590 campaign against Odawara. Hideyoshi was the military ruler whose campaign brought the Kanto region under Toyotomi control. Narita Ujinaga, the castle lord, remained at Odawara Castle, while approximately 3,000 people defended Oshi, including warriors, local conscripts, farmers, and townspeople.
Ishida Mitsunari commanded the Toyotomi assault, with Otani Yoshitsugu, Nagatsuka Masaie, Sanada Masayuki, and other commanders taking part. The besiegers constructed the approximately 28-kilometre Ishida Embankment and tried to flood the castle with water from the Tone River. Oshi Castle endured the attack and its defenders surrendered only after learning that Odawara Castle had fallen. This episode gave rise to the tradition of the “Floating Castle of Oshi.”
Tradition credits Kaihime, the daughter of Narita Ujinaga, with an important part in the defense. Historical documents concerning this tradition remain under investigation, so her role belongs chiefly to the castle’s continuing historical tradition rather than to a settled account of the siege.
Oshi Domain under Tokugawa rule
After Tokugawa Ieyasu assumed control of the Kanto region, Oshi became the administrative centre of the 100,000-koku Oshi Domain. A koku was a historical measure of agricultural productivity, conventionally based on the rice needed to support one person for a year, making this rating an indication of a substantial feudal territory.
The domain was initially assigned to Ieyasu’s fourth son, Matsudaira Tadayoshi. Because Tadayoshi was still a child, Matsudaira Ietada managed the domain. Tadayoshi moved to Kiyosu in 1600, and Oshi subsequently came under direct shogunal administration before later returning to the rule of Matsudaira and Abe branches.
Matsudaira Nobutsuna entered Oshi in 1633 and transferred to Kawagoe in 1639. Abe Tadaaki then became lord, and the Abe family retained the castle until Abe Masanori was transferred to Shirakawa in 1823. A branch of the Matsudaira family governed Oshi thereafter until the Meiji period, which began after the 1868 political transformation that restored imperial government.
Expansion, abandonment, and commemoration
The castle was expanded and improved during the Abe administration, beginning in the Kan’ei period from 1624 to 1643. Its later layout was considered complete around 1702. The castle town prospered as a post station on a branch route associated with the Nakasendo, one of the principal roads linking Edo and Kyoto through central Japan. Tone River shipping also supported the town’s role as a distribution centre. From the late Edo period, Gyoda became known for producing tabi, traditional Japanese split-toe socks.
The abolition of the domains in 1871 brought the Oshi prefectural office to the Ninomaru for approximately three months. The castle was then abandoned, and most of its structures were demolished in 1873. The grounds became Narita Park in 1875 and Oshi Park in 1894. Oshi Castle later received designation as a Saitama Prefecture historic site. In 2017, it became part of the Japan Heritage story concerning Gyoda’s traditional tabi-storehouse district and was selected as No. 118 in the Continued 100 Famous Castles of Japan.
Remains
Marshland setting and defensive layout
Oshi was built across an extensive marshland on an alluvial fan between the Tone River to the north and the Arakawa River to the south. Rather than filling the wetlands, its builders used naturally occurring islands and natural levees as the foundation of the defense. Separate islands served as baileys, or enclosed functional areas within a Japanese castle, and bridges connected them. Residences occupied the Ninomaru, while the surrounding marshes, watercourses, moats, and earthworks created a defensive landscape that was difficult to attack.
Part of the Honmaru earthwork survives. Traces of the former marshland and water defenses can be seen in Suijo Park, where the outer moat was incorporated in 1964. The surrounding moat had been partly filled in 1883, using soil taken from nearby burial mounds. These surviving earthworks, water traces, and altered park spaces preserve the relationship between the castle and the wetland terrain that shaped its original design.
Castle tower
The historical three-story, three-tiered tower was built around 1701 in the style of a yagura, a Japanese castle tower used for lookout, defense, storage, or signaling. A reinforced-concrete reconstruction was erected in 1988 on or near the Honmaru site as part of the Gyoda City Local History Museum. Its position and scale differ from those of the historical tower, while its interior contains an observation room and exhibitions on Gyoda’s history.
The reconstruction drew on a historical bird’s-eye view of the castle and documentary material. The present tower therefore belongs to the modern interpretation of the Honmaru landscape, while the surviving earthworks, archaeological remains, and relocated gates represent other phases of the castle’s physical development.
Relocated gates and surviving features
Kitatani Gate
The Kitatani Gate survives after being relocated to Soganji Temple in Kazo. Its preservation away from the former castle grounds retains a physical element of Oshi’s entrance system and connects the surviving gate to the castle’s earlier material fabric.
Koraimon-style gate
A castle gate of uncertain original identity survives beside the local-history museum’s parking area. It is built in the Koraimon style, a gate form associated with a roofed entrance structure, and provides another surviving example of the castle’s former architectural elements.
Shinshukan domain-school gate
The gate of the former Shinshukan domain school survives after relocation to a position south of the museum. Although associated with the domain’s educational institution rather than described as part of the original castle layout, it preserves a feature from the wider administrative landscape of Oshi Domain.
