Sunday, March 20, 2022

Koshigoe Castle –Castle move around hill to reach core part-

 Koshigoe Castle

-Castle move around hill to reach core part-



Name: Koshigoe Castle (Koshigoe-jo)

Place: Koshigoe Ogawa town, Saitama
Location: 36.04517278685016, 139.23139410782917
Type: Hill Castle
Built: 15th century?
Remaining remnants: Clay walls and dry moats 

Brief History

Koshigoe castle (腰越城) is located at the peninsular like hill formed by U letter like meandering Tsuki-kawa river at the west edge of Ogawa basin, Current road runs along with the river, but as it is not so high hill there might be a old road straightly crossed the root of the ridge, assumed by the name of “Koshigoe” (Japanese word means passing the height).

Castle site is a choke point between Ogawa basin and upstream valley of Tsuki-kawa river named Ogawara-valley, that is not only certain space residential area now is used as the center of Higashi-Chichibu village, but also a mountain road passing Sadamine-toge pass toward Chichibu area. Koshigoe-castle worked both for defense of local area and control of wide area traffic.

Origin of Ueda clan and Koshigoe castle

Precise year is unknown but Koshigoe castle might be built as a home castle of Yamada clan, that was a retainer of Ueda clan. Ueda clan is a large size local lord of Musashi province that is derive from seven local samurai group of the province, and as a retainer of Ogigayatsu Uesugi clan it entered into Hiki area and placed their home ground at Ogawara valley around 15th century, then Koshigoe castle might be built at this time.

The main family of Ueda clan became the deputy governor of Sagami province (Kanagawa prefecture) under Ogigayatsu Uesugi clan and protected Gongenyama castle at current Yokohama city, but raised against their master in connection with Hojo clan. This rise was broken by Uesugi clan and main family of Ueda clan disappeared, but branch family remained at Hiki area continuously served to Ogigayatsu Uesugi clan.

Important retainer of Ogigayatsu Uesugi clan

At the east edge of Hiki area that was a territory of Ueda clan there was Musashi Matsuyama castle (Saitama prefecture) that was originally a branch castle of Ueda clan but later became an important base of Ogigayatsu Uesugi clan and protected by their important retainer Nanbada clan. In 1537 Kawagoe castle (Saitama prefecture), the main base of Ogigayatsu Uesugi clan was fell by Hojo clan, then Tomosada Uesugi (1525-1546), the Ogigayatsu Uesugi clan moved to Musashi Matsuyama castle and kept resistance against Hojo clan.

In 1546, an alliance of Ogigayatsu Uesugi clan and Yamanouchi Uesugi clan fiercely attacked Kawagoe castle close to fall, but faced night attack of Hojo army and suffered severe defeat, losing its leader Tomonao Uesugi. Nanbada clan also died in the battle then Hojo army occupied empty Musashi Matsuyama castle.

At this battle Masahiro Ueda (?-1571), the leader of Ueda clan, was recorded to escape to Koshigoe castle, probably to protect their home land against Hojo clan. But next year Sukemasa Ota (1522-1591), another former important retainer of Ogigayatsu Uesugi clan, recovered Musashi Matsuyama castle. Further Sukemasa recovered Iwatsuki castle (Saitama prefecture), then moved to Iwatsuki castle and placed Tomonao Ueda (1494-1582), son of Masahiro Ueda, as the commander of Musashi Matsuyama castle.

Among two large power

However, Tomonao Ueda suddenly turned to Hojo clan with Musashi Matsuyama castle Ueda clan became an important retainer of Hojo clan. But in 1561 Kenshin Uesugi (1530-1578) who was the governor of Echigo province (Niigata prefecture) made expediton against Hojo clan, and Ueda clan followed to Kenshin Uesugi.

At this time Kenshin Uesugi placed Sukemasa Ota as the commander of Musashi Matsuyama castle but soon retreated to Echigo province. Ueda clan returned to Hojo clan, and in 1563 Hojo clan and Takeda clan jointly attacked Musashi Matsuyama castle. Uesugi clan sent reinforcement army but was blocked, then Musashi Matsuyama castle became the territory of Hojo clan again.

Hojo clan placed Tomonao Ueda as the commander of Musashi Matsuyama castle again, and ordered to protect Musashi Matsuyama castle, Koshigoe castle and Aoyama castle. Koshigoe castle and Aoyama castle existed at west and south edge of Ogawa basin, both were the territories of Hojo basin but still unstable situation after the invasion of Kenshin Uesugi. After that Koshigoe castle might be treated as a major branch castle of Ueda territory and might be improved.

Structure of Koshigoe castle

Koshigoe castle stands at the edge of peninsular like hill spreads from northward to southward. Basically the height of the hill goes down southward, but at the north of castle there is a saddle point which was also used as a direct pass crossed the hill, then castle was built utilizing height difference of the saddle point and small peak at the south.

As the peak that is used as the central area directly faced, castle road round clockwise at the east slope of the hill toward south, crossing vertical dry moats and passing narrow corridor between the slope and clay wall. After that the road became wide corridor area, then crosses large dry moat divides the ridge and turned to west slope. Then the road climb up folded road and passed buffer area to the top of the ridge the headed to the peak.

Peak area consist of lower secondary area of 30 meter long and 10 meter wide, and upper central area that is 30 meter long and 20 meter wide with clay wall at westward. Total size of the castle is a isosceles triangle of 300 meter long and 150 meter wide, and that is mainly built by clay wall but partially uses stone walls.

Afterward of Koshigoe castle and Ueda clan

By 1566 Uesugi army substantially retreated from Musashi province and Hiki area became stable under Ueda clan. In 1569 Hojo clan and Takeda clan once broke and Takeda army intruded into Hojo territory from Usui-toge pass, but there was no record of battle at this time.

Ueda clan kept its position as the lord of Hiki area and commander of Musashi Matsuyama castle until 1590, but Hojo clan was ruined by central ruler Hideyoshi Toyotomi at that year and Ueda clan also disappeared from history along with Hojo clan. At this battle Musashi Matsuyama castle was attacked by Toyotomi army and opened, but Koshigoe castle might not be used and after the battle it was abolished along with other branch castles.

Now no building remains but structure of the castle well remain on the hill. There is only one route from saddle point toward hilltop central area, but it is a thrilling one down and up then passing narrow and folded path. Even though small but it is carefully built by combination of various parts, that is a common element of castles built under Ueda clan such as Musashi Matsuyama castle or Ogura castle slightly but clearly different from Hojo clan.


30 minutes drive from Kanetsu Jidoshado Expressway Ranzan-Ogawa interchange to parking of "Patria Ogawa". 30 minutes walk from parking to hilltop castle.

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Pictures (click to enlarge)