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Castle Karasawayama Castle

This article is in the series Walking the Japanese Castles
Karasawayama Castle (唐沢山城) is a hilltop castle built on Mount Karasawa (elevation 247 metres) and located about five kilometres north of Sano City, Tochigi Prefecture.



According to legend, Fujiwara no Hidesato (藤原秀郷) built the castle in the 10th century. Hidesato was also known under the name Tawara Tōda (田原藤太) and famous for allegedly killing a monster centipede in Ōmi Province (modern-day Shiga). He suppressed the rebellion of Taira no Masakado in the year 940. In 1491, Sano Hidetsuna (佐野秀綱, 1472-1548) rebuilt the castle. The Sano were descendants of Hidesato and remained the lords of the castle.

In the Sengoku Period, the Sano were drawn into a vortex of conflicts between the Uesugi of Echigo and the Hōjō of Sagami. Karasawayama Castle became the stage of repeated battles. Uesugi Kenshin attacked the castle several times, almost every year in the 1560s. As the Sano repelled Kenshin many times, Karasawayama Castle developed the reputation of being the most impregnable castle in the northern Kantō region. In reality, the Sano often surrendered to Kenshin to avoid costly battles.

The Sano survived by pledging allegiance to Toyotomi Hideyoshi and Tokugawa Ieyasu. In the end, however, they had to abandon Karasawayama Castle because the Edo shogunate did not tolerate a fortress so strong so close to the capital. The Sano eventually moved to Sano Castle.

Nowadays, Karasawayama Shrine (唐沢山神社) is located on the grounds of the former castle site.

The topography of Karasawayama Castle reveals steep slopes surrounding the mountain, complicated ridges and swamps, and a relatively vast flat area on the hilltop; all of these features converge to an impregnable fortress. The official website of Sano City linked below has more detailed information on the topography of the castle.



The map is based on the Digital Japan Portal Web Site powered by the Geospatial Information Authority of Japan.


I went to Karasawa Yamashiro by car. Up the steep slopes is a rest house and a parking lot. The hilltop is full of the tourists who visit Mt. Karasawa for its natural beauty.

① The site of Otemon (追手門)


② Masugata Gate (桝形門); the entrance to the castle site.


③ Tengu Rock, the location of the former watchtower.


④ Ooi-no-i Well (大炊井): as a result of a prayer to the god of Itsukushima Daimyōjin (厳島大明神) and an ensuing dream, a well was dug at this spot during the construction of the castle. Water gushed up and has never dried up. The water seems beautifully blue, but I did not dare not to drink it.


⑤ This is the God Bridge spanning across the moat. Of course, the historical bridge was not made of robust stones, but a drawbridge.


⑥ A beltlike enclosure next to the third enclosure (三の丸 san-no-maru). The earthwork is well preserved.


⑦ The site of the second enclosure (二の丸 ni-no-maru. The was the location of the guardhouse for the inner castle.


Around the main enclosure (本丸 honmaru), a lot of stone walls are left. The top photograph is a tall stone wall which is quite rare for hilltop castles in Kantō.
on the lower photograph, the tree roots grow deeply into the stone.



⑧ The site of the honmaru. Now, there are the main structures of the shrine.


⑨ The view from the southern enclosure. On clear days, the high-rise buildings of Shinjuku and Tokyo Sky Tree are visible in the distance. Legend has it that once the lord saw a fire in Edo from here and hurried to the city to help, but the shōgun found it outrageous that the Sano were able to look down on Edo. They had to abandon the castle and move to Sano Castle.


That is a well beside the honmaru. The water was said to be used for tea ceremonies. The abundance of water is one of the conditions that make a castle impregnable.


⑩ Ohana-batake (botanical garden) where medicinal herbs were cultivated.


⑪ The site of the Gold Enclosure (金の丸), the former location of the treasury.


⑫ The site of the northern enclosure where the princess used to reside. Now, the area is used as a camping ground.


Date of visit: 22 September 2013


  • Address: Fuji-cho, Sano-shi, Tochigi
  • Transport: 1-hour walk from Tobu Sano Line Tanuma Station
    4 kilometres from Kita-Kanto Expressway Sano-Tanuma Interchange via Prefectural Route 115
  • Other sights: Karasawayama Shrine (in the castle site)
    Sano City Sightseeing, Sano Castle


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Hiroto Uehara
Hiroto is an ordinary Japanese office worker, but his true mission is searching for castles on the weekend.


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