Odawara Castle

Odawara Castle has exhibits that introduce the history of the castle from the Edo period to the present day, as well as materials related to samurai culture, all of which are displayed inside the castle tower.

Armor, swords, illustrated maps, old documents, and other valuable materials tell the history of Odawara.

Visitors can also experience and learn about the existence of the Fuuma Ninja, who supported the Hojo clan during the Warring States period, at the NINJA-kan.

From the top floor, about 60 meters above sea level, visitors can enjoy a panoramic view of Sagami Bay and the Boso Peninsula.

Odawara Castle was the predecessor of Odawara Castle, a mountain castle built in the middle of the 15th century by the Omori clan, who expanded into western Sagami during the Muromachi period.

Later, Soun Hojo captured the castle, and it reigned as the residence of the Hojo clan in the Kanto region.

During the Warring States Period, the castle was expanded and improved as the central base of the Kanto region, and the general structure surrounding the castle was completed in preparation for an attack by Toyotomi Hideyoshi, making it the largest medieval castle in Japan.

In the Edo period, Odawara Castle came under the control of Tokugawa Ieyasu, and the Okubo and Inaba clans became the castle lords. The castle underwent extensive renovations and was reborn as a modern castle fortress.

The castle was abandoned in 1872, and many of the buildings were demolished, and the remaining stone walls collapsed in the Great Kanto Earthquake.

Today, the ruins of Odawara Castle are designated as a national historic site, and parts of the Honmaru and Ninomaru have been preserved. In addition, the castle ruins park has been developed around the Honmaru, and the castle tower, Tokiwamokimon, Domon (copper gate), and Umadegumon (horse gate) have been restored. The castle has been selected as one of the 100 best castles in Japan.

Visitors to Odawara Joshi Park can enjoy a variety of flowers and plants throughout the year. Visitors can appreciate seasonal flowers such as cherry blossoms, wisteria, irises, and plum blossoms. You can also see giant trees that are over 500 years old.

At the iris garden located on the east moat of the Honmaru, about 10,000 irises bloom from early to mid-June. At night, the garden is illuminated, creating a fantastic sight.

The following is a partial list of people associated with Odawara Castle:

Hojo Soun (1432-1519): A feudal lord and founder of the Hojo clan. While serving the Imagawa clan, he became independent and took Izu. Later, he advanced to Odawara and ruled Izu and Sagami, laying the foundation for the later five generations of the Hojo clan.
Hojo Ujitsuna (1487-1541): A feudal lord and son of Hojo Soun. He changed his family name to Hojo, rebuilt Tsurugaoka Hachiman Shrine, and used the tiger seal to establish a new territorial ruling system, expanding his power in southern Musashi. He made Odawara his residence and devoted himself to its prosperity.
Ujiyasu Hojo (1515-1571): A feudal lord and the eldest son of Ujitsuna Hojo. He drove Uesugi Norimasa, the Kanto governor, to Echigo and established relations with Takeda Shingen and the Imagawa clan to oppose Uesugi Kenshin. He also excelled in civil administration, reforming the taxation system and establishing a system of horse transmission.
Hojo Ujimasa (1541-1590): A feudal lord and second son of Ujiyasu Hojo. He expanded his power through repeated conflicts and peace with Takeda Shingen and Uesugi Kenshin. He was defeated in the Battle of Odawara due to a conflict with Toyotomi Hideyoshi, and committed suicide.
Hojo Ujinao (1562-1591): A feudal lord and second son of Hojo Ujimasa. He succeeded Ujimasa after he retired, drove out Takigawa Kazumasa, a vassal of Oda Nobunaga, from the Kanto region, and made peace with Tokugawa Ieyasu, but was defeated by Toyotomi Hideyoshi and banished to Koyasan. He was later pardoned and given a fief of 10,000 koku, but died of illness in Osaka.
Okubo Tadamasa (1781-1837): A feudal lord of the Odawara domain in the late Edo period. He was also active as an old lieutenant, issued a decree of thrift in the domain government, and established the Shuseikan, an academy to foster the development of human resources.

Odawara Castle

Odawara Castle, located in Odawara City, Kanagawa Prefecture, is a flat mountain castle that flourished from the Warring States Period to the Edo Period. It is known as the headquarters of the Hojo clan, and during the Edo period, it was used as the domain office of the Odawara han (feudal domain). It is now designated as a national historic site.

The castle features a beautiful garden with 800 cherry trees in bloom inside the castle. In addition, many azaleas are planted, attracting visitors.

Odawara Castle was the residence of the Hojo clan, which used Mt. Although the specific builder of the castle is unknown, it is commonly believed that the castle was built by the Omori clan before the Hojo clan. However, there is another theory that the castle was located near the present north moat of San-no-maru during the Omori clan period.

The castle was known as an impregnable castle during the reign of Ujiyasu Hojo, and withstood attacks by Kenshin Uesugi and Shingen Takeda.

During the Edo period (1603-1867), the castle was renovated as a modern castle and became the main part of the current Odawara castle site, but Hachiman-yama was abandoned, resulting in the unusual coexistence of medieval and modern castle structures.

The most distinctive feature of Odawara Castle is the vast outer wall, which was built to oppose the Toyotomi forces. This outer wall encircles the entire town of Odawara with earthworks and empty moats, and is approximately 9 kilometers in length.

It is said to have surpassed the structure of Toyotomi Osaka Castle, but Ieyasu Tokugawa had it removed in 1614.

Parts of it remain today and are shown on old maps. The lord of the castle later became the Okubo clan, but the castle suffered damage from two major earthquakes during the Edo period. The rebuilt castle tower existed until 1706.

Structure

Plain part

The part of the castle renovated in modern times by Tadayo Okubo and Masakatsu Inaba is the area around the current Odawara Castle Site Park. This part of the castle was built entirely of stone walls, which is unique in the Kanto region, where many castles have only earthen mounds. This is because Odawara Castle was considered important as the entrance to the Kanto region.

It was not until after the large-scale renovation that began in 1632 that the castle took on its current form with all-stone walls. The main circle was centered, with Ninomaru and Sanomaru overlapping to the east. To the west of the main circle was Byobuiwa Curve, Komine Curve to the south, and Mikurome Curve to the north.

In addition, there were four other smaller curves, Takabe-curuma, Ochatsubo-curuma, Umaya-curuma, and Bensaiten-curuma, which served as horse stalls.

The main castle tower and the square-shaped Tokiwamokimon gate were located in Honmaru, and the residence, copper gate, and flat turrets were located in Ninomaru. Odawara Castle as a whole is thought to have had about 13 castle gates and 8 turrets. At the end of the Edo period, three gun batteries were also built on the coast.

Most of the buildings were demolished in the early Meiji period (1868-1912), but the Honmaru, Ninomaru, Chabotsu-gurinawa, and Umaya-gurinawa are being restored. A library and local culture center were established in Takabe-gurinawa, Houtoku Ninomiya Shrine in Komine-gurinawa, and an amusement park in Byoubuwa-gurinawa.

Mikuranome-gurinawa was once used as a ball field, and is currently being restored and maintained. Benzaiten Curtain Circle is a residential area outside of the castle ruins park, and the Asahigaoka High School site is also located there.

Also on city-owned land adjacent to Odawara Joshi Park was the Odawara Hakone Chamber of Commerce and Industry’s Hall of Commerce and Industry, which was built in 1971.

However, although the Chamber of Commerce and Industry building was built with permission from the Agency for Cultural Affairs, it was difficult to rebuild because the Benzaiten Circle and lotus pond were within the scope of the national historic site designation. Therefore, the Odawara Hakone Chamber of Commerce and Industry intends to move to a new office in 2021 and donate the old Commerce and Industry Hall to the city.

Hachimanyama Kogaku

Hachimanyama Kogaku is a fortification against the plain. It is believed to be the site where Ujimasa Hojo took up camp during the Battle of Odawara. It is a continuous structure consisting of a main circle, a west circle, Fujiwara-daira (Fujiwara Plain), and Poison Enokidaira (Poison Enokidaira).

South of the Main Circle is the South Circle, and north of the West Circle is the Forge Circle, reinforcing the defenses.

Today, most of the area is residential. Part of the East Circular Wheel remains as a historic park, but the Main Circular Wheel, its north side, and the South Circular Wheel are residential areas.

The West and Fujiwara-daira areas are now Odawara High School, the Kaji-curve area is a garden tennis field, and the Poison Enokidaira area is a water reservoir and Shiroyama Park. Little remains of the old days.

General Structure

Ren Sen earthen mound

The core of Odawara Castle is surrounded in three layers by the Ninomaru moat, the Sanomaru moat, and the Soukouchi moat. The Ninomaru moat is a connection of moats on the plain and around the Hachimanyama old enclosure.

The san-no-maru moat consists of the san-no-maru moat of the early modern fortification section, an empty moat along the ridge of Tenjinyama Hill to the south, and the Kobine moat at the westernmost end. The Komine moat is the largest structure in the medieval castle section.

It is located where the Hachimanyama, Tenjinyama, and Yatsu hills converge, separating each hill from the mountainous area to the west. As mentioned above, the total moat is a continuous series of empty moats and water moats surrounding the entire town of Odawara.

The moat in the mountainous area incorporates the highest point of Odawara Castle, the bell tower, further west of the Komine moat, and the moats in the northwestern area from there to Sakurababa and Inari-mori are relatively well preserved.

The water moats on the plains have disappeared or been buried underground, but a few earthen mounds remain around Hayakawaguchi in the southwest and Ren Sen in the east.

History and Milestones

Odawara Castle is said to have originated in the late Heian period (794-1185) as the residence of the Kobayakawa Tohei, a member of the Dohi clan, a powerful family in Sagami Province. According to “Hachiki Monogatari,” an anecdote exists that the castle was given to Sano Genzaemon by Hojo Tokiyori.

In 1416, the Dohi clan, which had been on the side of Zenhide Uesugi during the Uesugi Zenhide Rebellion, was defeated, and the Omori clan took Odawara Castle and expanded its power to Sagami and Izu provinces.

In 1495, Ise Moritoki (Hojo Soun), a descendant of the Ise Taira clan that ruled Izu Province, took Odawara Castle from Omori Toryori and greatly expanded the castle. However, some old documents record that the Omori clan was still the lord of the castle, so the actual timing of the seizure is not clear.

It is believed that Moritoki used Nirayama Castle as his base, and that his son, Ise Ujitsuna (later Hojo Ujitsuna), took Odawara Castle as his base. The castle was used as a residence for five generations of the Hojo clan until the time of Hojo Ujimasa and Hojo Ujinao, father and son, and became the political center of the southern Kanto region.

In 1561, Uesugi Kenshin, who had been a rival to the Go-Hojo clan in the northern Kanto region, invaded from Echigo, and the Battle of Odawara Castle broke out. The Uesugi forces surrounded the castle with a huge army, said to number about 113,000 men (according to the Kankyashu Kosenroku).

The siege lasted about a month, and it is said that the Uesugi forces repulsed the attack, but in reality, the siege lasted about 10 days.

In 1568, Shingen Takeda launched an invasion of the Suruga Imagawa domain, and the Go-Hojo clan broke off the Koso alliance and formed an alliance with the Echigo Uesugi clan to oppose Takeda. Shingen responded by forming an alliance with the northern Kanto provinces to increase pressure on the Go-Hojo domain.

In his attack on Odawara in Eiroku 12, Shingen surrounded Odawara Castle, but as he retreated, he defeated the Go-Hokujo forces at the Battle of Sanmasu Pass. Later, the Go-Hojo recognized Takeda’s possession of Suruga and restored the Kousou alliance.

It is believed that the Odawara offensive was not a full-scale invasion, but merely an act of military demonstration.

It is said that the Go-Hojo clan rebuilt Odawara Castle at least twice. The first reconstruction took place shortly after Ise Moritoki (Hojo Soun) acquired the castle, which is said to have been the site of a major earthquake.

Many documents of reconstruction were also issued between 1566 and 1569, and it is believed that the castle was prepared for invasions by the Uesugi and Takeda clans. Odawara Castle was considered important as the headquarters of the Go-Hojo clan, and was the center of a struggle with Sunto-gun in Suruga Province, which is why it was reconstructed.

In 1590, Toyotomi Hideyoshi, in the final stage of his unification of the country, found himself in a state of battle with the Hojo clan, led by the retired Hojo Ujimasa and Ujinao.

Together with Satake Yoshishige and Utsunomiya Kunitsuna, feudal lords from the Kanto region, they attacked Odawara Castle with a huge army numbering in the hundreds of thousands. This battle is known as the Odawara Conquest (also known as the Odawara Battle or the Odawara War).

Hideyoshi brought with him a vast amount of supplies and attacked Hojo’s tributary castles individually, waiting for the enemy to run out of provisions and frustrating their counterattack.

After three months of siege warfare, the castle was opened almost without bloodshed. The dispute between Hojo and Hideyoshi over whether to make peace or continue the war was later known as the “Odawara Hyōtei,” or the “Odawara Review.

Hideyoshi and Kunitsuna then moved their camp to Utsunomiya, where they decided on the treatment of the feudal lords of the Tohoku region and completed the unification of the country.

After the Edo Period

After the war, the territory of the Hojo clan was given to Tokugawa Ieyasu, who chose Edo Castle as his residence, and placed his inner circle, Tadayo Okubo, at Odawara Castle.

The old Odawara Castle was a huge fortress that included the city center, but its scale was reduced during the reign of the Okubo clan, and the Okubo clan remained the lord of the castle until the Meiji period.

On the other hand, the Hojo clan ruled Sayama in Kawachi Province (present-day Sayama City, Osaka Prefecture) as an outlying feudal lord in the Meiji era (1868-1912) under Ujimori Hojo.

Modern Times

Between 1870 and 1872, most of the buildings in the castle were demolished and the Okubo Shrine was built on the castle tower.
In 1901, the Odawara Imperial Villa was established in the old castle.
In 1909, the only remaining Ninomaru flat turret was restored.
The Imperial Villa was severely damaged in the Great Kanto Earthquake of 1923, and was subsequently closed. The Ninomaru Flat Yagura also collapsed, and most of the stone walls also fell.
Between 1930 and 1931, the stone walls were reconstructed, but they were piled lower than before, and their original appearance was lost.
In 1935, the collapsed Ninomaru flat turret was rebuilt as a corner turret, but its size was reduced to one-half of the original due to budget constraints.
In 1950, work began on the castle tower that collapsed in the Great Kanto Earthquake. Later, the Odawara castle ruins were reorganized as Odawara Castle Park.
In 1953, the masonry work on the castle tower was completed. Later, as a commemorative project for the 20th anniversary of the establishment of Odawara City, reconstruction of the castle tower was planned, based on a model of the existing old tower. For a time, a Ferris wheel was installed on the keep.
The reconstruction of the keep was completed on May 25, 1960. However, the reconstructed keep is a reinforced concrete structure, and at the request of Odawara City, a railing was installed on the top floor of the keep, so it is not a faithful reproduction of the original appearance. The castle tower offers a clear view of the Pacific Ocean and the stone walled mountain castle on Mount Kasagake.

Currently, Odawara City is moving forward with a plan to restore the central part of the castle to its late-Edo period appearance, and efforts have been made to rebuild the castle tower and other parts of the castle.

The exterior of the Tokiwagimon gate was restored in 1971, the Sumiyoshi Bridge in 1990, the Domon gate in 1997, and the Bade-mon gate in 2009. In 2006, the castle was selected as one of the 100 best castles in Japan.

In 2013, the NPO “Minna de Ojo wo Tsukuru Kai” was established with the aim of restoring the wooden structure, and from 2015 to 2016, seismic work and restoration of the walls and roof took place. 2016 saw the reopening of the castle. 2018 saw the first drainage and cleaning of the moat in 38 years.