is a "yamashiro"-style (

castle A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified r ...

located on Mount Iwabitsu in Higashiagatsuma,

Gunma Prefecture is a prefecture of Japan located in the Kantō region of Honshu. Gunma Prefecture has a population of 1,937,626 (1 October 2019) and has a geographic area of 6,362 km2 (2,456 sq mi). Gunma Prefecture borders Niigata Prefecture and Fukushima ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

. The ruins have been protected by the central government as a National Historic Site since 2019.

Overview

Iwabitsu Castle is located in northwestern Gunma Prefecture in the middle of a long valley created by the

Agatsuma River Agatsuma may refer to: *, Japanese shamisen player *Agatsuma District, Gunma, a district in Gunma Prefecture, Japan *Agatsuma, Gunma, a town in Gunma Prefecture, Japan *Agatsuma River, a river in Japan *Agatsuma Entertainment, a Japanese toy/video ...

(a tributary of the

Tone River The is a river in the Kantō region of Japan. It is in length (the second longest in Japan after the Shinano) and has a drainage area of (the largest in Japan). It is nicknamed Bandō Tarō (); ''Bandō'' is an obsolete alias of the Kantō ...

). This valley was the route of the Shinshu Kaidō, a road which led from Takasaki to

Shinano Province or is an old province of Japan that is now Nagano Prefecture. Shinano bordered on Echigo, Etchū, Hida, Kai, Kōzuke, Mikawa, Mino, Musashi, Suruga, and Tōtōmi Provinces. The ancient capital was located near modern-day Matsumoto, whi ...

via the Torii Pass, and the castle thus controlled a strategic point on this highway.

History

The origins of the Iwabitsu Castle are uncertain, but it is believed to have been built by the local Agatsuma clan sometime in the 13th century. During the

Muromachi period The is a division of Japanese history running from approximately 1336 to 1573. The period marks the governance of the Muromachi or Ashikaga shogunate (''Muromachi bakufu'' or ''Ashikaga bakufu''), which was officially established in 1338 by t ...

, it was held by the Saitō clan, another local warlord. However, in the early

Sengoku period The was a period in History of Japan, Japanese history of near-constant civil war and social upheaval from 1467 to 1615. The Sengoku period was initiated by the Ōnin War in 1467 which collapsed the Feudalism, feudal system of Japan under the ...

, it was captured by

Sanada Yukitaka was a Japanese samurai warrior of the Sengoku period. He is known as one of the "Twenty-Four Generals of Takeda Shingen". He was the father of Sanada Nobutsuna and Sanada Masayuki and grandfather of the legendary samurai warrior Sanada Yukimur ...

, who had expanded from Shinano Province into northern

Kōzuke Province was a province of Japan in the area of Japan that is today Gunma Prefecture. Kōzuke bordered by Echigo, Shinano, Musashi and Shimotsuke Provinces. Its abbreviated form name was . Under the ''Engishiki'' classification system, Kōzuke was ran ...

with the backing of his overlord,

Takeda Shingen , of Kai Province, was a pre-eminent ''daimyō'' in feudal Japan. Known as the "Tiger of Kai", he was one of the most powerful daimyō with exceptional military prestige in the late stage of the Sengoku period. Shingen was a warlord of great ...

. The Saitō clan had turned to

Uesugi Kenshin , later known as was a Japanese ''daimyō''. He was born in Nagao clan, and after adoption into the Uesugi clan, ruled Echigo Province in the Sengoku period of Japan. He was one of the most powerful ''daimyō'' of the Sengoku period. Known as ...

Echigo Province was an old province in north-central Japan, on the shores of the Sea of Japan. It bordered on Uzen, Iwashiro, Kōzuke, Shinano, and Etchū Provinces. Nussbaum, Louis-Frédéric. (2005). "''Echigo''" in . It corresponds today to Niigata ...

for assistance, but due to the distance from Echigo and the stratagems employed by the Sanada, the castle fell in 1563.

Sanada Masayuki was a Japanese Sengoku period lord and ''daimyō''. He was the head of Sanada clan,_a_regional_house_of_Shinano_Province.html" ;"title="DF 56 of 80/nowiki>">DF 56 of 80">("Sa ..., a regional house of Shinano Province">DF 56 of 80/nowiki>">DF 5 ...

used Iwabitsu Castle as his base to continue his expansion into northern Kōzuke, capturing

Numata Castle is a Japanese castle located in Numata, Gunma, Numata, northern Gunma Prefecture, Japan. At the end of the Edo period, Numata Castle was home to the Toki clan, ''daimyō'' of Numata Domain, but the castle was ruled by various clans over its histor ...

in 1579. He also rebuilt the Iwabitsu ''

jōkamachi The term refers to a type of urban structures in Japan in which the city surrounds a feudal lord's castle. These cities did not necessarily form around castles after the Edo period; some are known as Jin'yamachi, cities that have evolved around J ...

'' into a fortified ''

shukuba were post stations during the Edo period in Japan, generally located on one of the Edo Five Routes or one of its sub-routes. They were also called ''shuku-eki'' (宿駅). These post stations (or "post towns") were places where travelers could r ...

'' by surrounding the entire town with a series of forts and gates, similar to the layout which he later employed when designing the new stronghold for the

Takeda clan The was a Japanese samurai clan active from the late Heian period until the late 16th century. The clan was historically based in Kai Province in present-day Yamanashi Prefecture. The clan reached its greatest influence under the rule of Taked ...

Shinpu Castle was a Sengoku period ''hirayama''-style Japanese castle located in what is now part of the city of Nirasaki, Yamanashi prefecture. It was the primary fortress of the warlord Takeda Katsuyori. The ruins have been protected as a National Historic ...

as few years later. After the fall of the Takeda clan in 1582, Sanada Masayuki had planned to provide refuge for

Takeda Katsuyori was a Japanese ''daimyō'' of the Sengoku period, who was famed as the head of the Takeda clan and the successor to the legendary warlord Takeda Shingen. He was son in law of Hojo Ujiyasu. Early life He was the son of Shingen by the daughter ...

at Iwabitsu Castle, but Katsuyori was unable to reach it due to treachery by some of his remaining retainers and committed ''

seppuku , sometimes referred to as hara-kiri (, , a native Japanese kun reading), is a form of Japanese ritual suicide by disembowelment. It was originally reserved for samurai in their code of honour but was also practised by other Japanese people ...

''. The famed

samurai were the hereditary military nobility and officer caste of medieval and early-modern Japan from the late 12th century until their abolition in 1876. They were the well-paid retainers of the '' daimyo'' (the great feudal landholders). They h ...

Karasawa Genba was a samurai of the Sengoku period, in the 16th century of the common era, who served as an important retainer of the Sanada clan. Genba_was_allegedly_born_in_Sawatari,_Shinano_province.html" ;"title="DF 56 of 80/nowiki>">DF 56 of 80">("S .... G ...

was an officer at the castle. Following the establishment of a stable regime under

Toyotomi Hideyoshi , otherwise known as and , was a Japanese samurai and ''daimyō'' (feudal lord) of the late Sengoku period regarded as the second "Great Unifier" of Japan.Richard Holmes, The World Atlas of Warfare: Military Innovations that Changed the Cour ...

, Iwabitsu and Numata were awarded to

Sanada Nobuyuki was a Japanese samurai of the Sengoku period. He was the son of ''daimyō'' Sanada Masayuki and the older brother of Sanada Yukimura. Early life He was the first son of Sanada Masayuki and his wife, Kansho-in. His younger brother was Sanada Yuk ...

, while his father Masayuki retained

Ueda Castle is a Japanese castle located in Ueda, northern Nagano Prefecture, Japan. At the end of the Edo period, Ueda Castle was home to a cadet branch of the Matsudaira clan, ''daimyō'' of Ueda Domain, but the castle is better known for its association w ...

. Following the death of Toyotomi Hideyoshi, Sanada Masayuki remained loyal to

Toyotomi Hideyori was the son and designated successor of Toyotomi Hideyoshi, the general who first united all of Japan. His mother, Yodo-dono, was the niece of Oda Nobunaga. Early life Born in 1593, he was Hideyoshi's second son. The birth of Hideyori cre ...

and his regent

Ishida Mitsunari Ishida Mitsunari (, 1559 – November 6, 1600) was a Japanese samurai and military commander of the late Sengoku period of Japan. He is probably best remembered as the commander of the Western army in the Battle of Sekigahara following the A ...

, whereas Sanada Nobuyuki, sided with

Tokugawa Ieyasu was the founder and first ''shōgun'' of the Tokugawa Shogunate of Japan, which ruled Japan from 1603 until the Meiji Restoration in 1868. He was one of the three "Great Unifiers" of Japan, along with his former lord Oda Nobunaga and fellow ...

. With the victory by Tokugawa forces at the

Battle of Sekigahara The Battle of Sekigahara (Shinjitai: ; Kyūjitai: , Hepburn romanization: ''Sekigahara no Tatakai'') was a decisive battle on October 21, 1600 (Keichō 5, 15th day of the 9th month) in what is now Gifu prefecture, Japan, at the end of ...

in 1600, Sanada Nobuyuki was confirmed in his holdings in northern Kōzuke, but due to the

Tokugawa shogunate The Tokugawa shogunate (, Japanese 徳川幕府 ''Tokugawa bakufu''), also known as the , was the military government of Japan during the Edo period from 1603 to 1868. Nussbaum, Louis-Frédéric. (2005)"''Tokugawa-jidai''"in ''Japan Encyclopedia ...

’s rule of “one domain – one castle” in 1615, Iwabitsu Castle was abolished. The ''jōkamachi'' survived as post station on the highway, but was relocated closer to the Agatsuma River. At present, nothing survives of the original castle. The entrance to the site is approximately 30 minutes on foot from

Gunma-Haramachi Station is a passenger railway station in the town of Higashiagatsuma, Gunma, Higashiagatsuma, Gunma Prefecture, Japan, operated by East Japan Railway Company (JR East). Lines Gunma-Haramachi Station is a station on the Agatsuma Line, and is located 2 ...

on the

JR East The is a major passenger railway company in Japan and is the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as in Japanese. The company's headquarters are ...

Agatsuma Line Agatsuma may refer to: *, Japanese shamisen player *Agatsuma District, Gunma, a district in Gunma Prefecture, Japan *Agatsuma, Gunma, a town in Gunma Prefecture, Japan *Agatsuma River, a river in Japan *Agatsuma Entertainment, a Japanese toy/video ...

, followed by another 30 minute hike up the side of the mountain to reach the location of the

inner bailey The inner bailey or inner ward of a castle is the strongly fortified enclosure at the heart of a medieval castle.Friar, Stephen (2003). ''The Sutton Companion to Castles'', Sutton Publishing, Stroud, 2003, p. 22. It is protected by the outer w ...

. Iwabitsu Castle was listed as one of　the

Continued Top 100 Japanese Castles The is a list of 100 Japanese castle, castles, intended as a sequel of 100 Fine Castles of Japan. The castles were chosen for their significance in culture, history, and in their regions by the in 2017. Hokkaidō region Tōhoku region Kant ...

in 2017.

Literature

* * * *

References

{{Continued Top 100 Japanese Castles Castles in Gunma Prefecture Ruined castles in Japan Sanada clan Higashiagatsuma, Gunma

Overview

History

See also

Literature

References