Japan Castle Explorer: Ota Kanayama Castle -Impregnable castle with mystic atmosphere-

Ota Kanayama Castle

-Impregnable castle with mystic atmosphere-

Overview

Name: Ota Kanayama Castle (Ota Kanayama-jo)

Alias: Nita Kanayama-jo
Place: Kanayama-cho Ota city, Gunma

Location: 36.317197961688485, 139.37697235568456
Type: Mountain Castle
Built: Originally 15th century, expanded in 16th century
Remaining remnants: Stone walls, clay walls and dry moats
Title: 100 famous Japanese castles

Brief History

Ota Kanayama castle (太田金山城) is located in Kanayama mountain, a 200 meter tall and independent mountain located at the north of central Ota city. Ota city is located at the north edge of Kanto plain, and surrounded by two large rivers, Tone river and Watarase river.

Due to its geographical location, this area is a corridor from northwest Kanto plain such as Maebashi to eastern Kanto plain such as Utsunomiya, and had been a strategic point. Kanayama castle was an impregnable castle rejected attack of large power such as Uesugi clan or Hojo clan, and regarded as one of seven excellent castles of Kanto region along with Maebashi castle, Karasawayama castle, Kawagoe castle, Oshi castle, Utsunomiya castle and Tage castle.

Built and structure of castle

Kanayama castle was built by Iwamatsu clan in mid of 15th century, but later captured by Yura clan. Yura clan was originally a retainer of Iwamatsu clan, but they overthrow their master and became an independent lord at the beginning of 15th century.

Later Yura clan sent their relative as a leader of Ashikaga Nagao clan, a traditional house of Kanto region, and expanded their territory to surrounding areas, such as Kiryu castle, Ashikaga castle and Tatebayashi castle. Along with the growth of clan, Kanayama castle was expanded into a strong fortress.

Main areas of the castle spread whole part of the hilltop area of mountain, and central area is located at the highest place. A small valley before central area is used as a main gate, fully covered by stone walls and there exist one round shaped pond called as “Pond of Sun”. Outside main gate there is another pond called as “Pond of Moon”, also round shape and covered with stone. Combination of stone walls and ponds look like a religious facility and has a mystic atmosphere unique to this castle.

Connecting ridge is used as secondary area, and another edge of secondary area there is a complex gate using stone walls. Many terraces are built from hilltop to hillside area, and another lower hill in front of the castle named Hachioji-yama was also used as a part of castle.

The valley between two mountains were used as a house of retainers and castle town. The size of main areas is 1km long, and total area including surrounding forts exceeded 3km square. It is one of the largest castles in japan and suitable for a powerful lord.

Impregnable castle stand attack of large army

If condition allowed they might grew to a warlord, but at that time there were already two large power, Hojo clan and Uesugi clan, existed in Kanto region and made severe conflict. Thus it was inevitable for Yura clan to be affected by the movement of these two powers. But different from other small clans, with the impregnable castle, Yura clan could keep its autonomy for long time.

At first Yura clan belonged to Kenshin Uesugi (1530-1578), leader of Uesugi clan, but in 1566, considering surrounding environment Yura clan changed to Hojo clan. Furious Kenshin Uesugi ordered Satake clan, a warlord of Hitachi country (Ibaraki prefecture) to attack this castle and siege by himself, but Kanayama castle did not yield to fierce attack of Kenshin, who was later called as god of war.

Yura clan had kept a half independent status with Hojo clan, but in 1584, Hojo clan attempted to seize this area directly and confined the leaders of Yura clan who visited Odawara castle (Kanagawa prefecture), the main base of Hojo clan, for a greeting of new year. Just after that Hojo army attacked Kanayama castle, but the mother of captured leaders lead remaining army well and resisted over 15 months, and finally under the condition of returning captured leaders Yura clan voluntary opened Kanayama castle.

The reason of which Kanayama castle did not fall against large army might be the following;
1) Kanayama mountain is a independent hill and there is no connecting ridge which become weakpoint of castle
2) There is large space of hilltop area to keep many soldiers and planty of supplies
3) The castle had two ponds and many wells, then abundant water is supplied
4) The size of mountain was large and attacking side needed numerous soldiers to shut down supply line completely
5) Kenshin Uesugi attacked this castle by long expedition from nation Echigo country (Niigata prefecture) and could not stay long to siege the castle. Hojyo clan was more closer but they had other enemies in different fronts, thus they also could not devote themselves to thie castle long time.
6) Yura clan kept other secure castles such as Tatebayashi castle or Kiryu castle, thus these castle could provide support to Kanayama castle.

Considering other examples such as Odani castle or Gassan Toda castle, to capture castle of this size, siege by several dozen thousands of soldiers for over one year was necessary.

Afterward of Yura clan and Kanayama castle

After the leave, Yura clan moved to Kiryu castle and continued as a small retainer under Edo shogunate. Kanayama castle itself was used by Hojo clan after the leave of Yura clan, and the castle was abolished along with the extinction of Hojo clan in 1590. The castle was once destructed but recently central areas were restored, and we can enjoy magnificent stone terraces rarely seen in Kanto region.