Sakato-jo Castle (坂戸城)

Sakato-jo Castle was a large-scaled yamashiro (a castle located on a mountain) that existed in Minamiuonuma City, Niigata Prefecture. Ancient structural remnants of the Honmaru (the keep of the castle) are located at the top of Sakato-yama Mountain, and those of residences used in peacetime can be found at the foot of the mountain. Spanning the Uono-gawa River, the castle was located at a strategic transportation point that commanded a view of the Mikuni-kaido road. On June 11, 1979, the area was designated as a national historic site. It is known that the castle is connected to the Ueda Nagao family, and the castle is also famous as the one that Masakage NAGAO, Kagekatsu UESUGI and Kanetsugu NAOE used as a base. Sento-in, an older sister of Kenshin UESUGI, lived there after her marriage. It is known that after Kagekatsu UESUGI was moved to Aizu and the Hori clan moved to Echigo, Naoyori HORI became the lord of the castle.


In the medieval period, Ueda-sho Manor was in the southern part of Uonuma County (present Minami-Uonuma County), and around the Kamakura Period, the area was under the control of the Nitta clan of the Seiwa-Genji (Minamoto clan) line. Although it is supposed that a castle had already been built on Sakato-yama Mountain at this time, placed at the center of the manor, it is considered that it was in the period of the Northern and Southern Courts (Japan) or later that the castle was constructed on a large scale.

In the period of the Northern and Southern Courts, the Uesugi clan supported the Northern Court and ousted the Nitta clan and others who supported the Southern Court from the southern part of Echigo Province. The Uesugi clan was appointed to the position of Shugo (provincial constable) of Echigo in the era of Noriaki UESUGI. Following this, a family member of Takakage NAGAO, a vassal of Noriaki, came to own Ueda-sho Manor between 1352 and 1355, called himself of the UEDA NAGAO clan and used the castle on Sakato-yama Mountain as his base. The information above has been handed down orally. After this, the UEDA NAGAO clan, together with the Nagao clan, who were the Shugodai (deputy of the Shugo), occupied important positions in Echigo Province. The Sakato-jo castle which the clan used as its base played important roles because of the following reasons: It was located at a place enabling the control of overland traffic connecting Echigo-Fuchu (present Naoetsu area of Joetsu City) and the Kanto Plain, was located at a strategic place for traffic using the Uono-gawa River and was also at a strategic place economically, centering on rice production in the Uonuma area.

In 1507, Tamekage NAGAO, the Shugodai, rallied Kokujin-shu (local samurai) in Echigo and expelled Fusayoshi UESUGI, the Shugo. In 1510, Tamekage had Akisada UESUGI, Kanto Kanrei (a shogunal deputy for the Kanto region), killed in the Battle of Nagamorihara, allowing him to hold sway in Echigo Province. The UEDA NAGAO clan kept a certain amount of independence from the Nagao clan, Shugodai. However, after the death of Tamekage, Kagetora NAGAO (Kenshin UESUGI) became Kokushu (head of provincial governors) of Echigo Province. It is said that with Sakato-jo castle surrounded by Kenshin UESUGI, Masakage NAGAO of the UEDA NAGAO clan surrendered to Kenshin in 1551, pledging his faith to him. After that, Masakage was successful in his life, but in 1564, he met a mysterious death while boating with Sadamitsu USAMI, the lord of Biwajima-jo Castle, who also perished.

After the death of Kenshin, Kagekatsu UESUGI, who was a son of Masakage and had been adopted by Kenshin, won the Otate War and became the lord of Kasugayama-jo Castle. Then "Ueda-shu" (an Ueda-named group of vassals) including Kanetsugu NAOE, whose father was a vassal of Masakage, formed a group of trusted vassals of Kagekatsu. At the same time, Sakato-jo Castle became a strategic site for managing the territory as an important branch castle of Kasugayma-jo Castle. Kanetsugu was also appointed as lord of Sakato-jo Castle.

In 1582, Kagekatsu fought with Nobunaga ODA's troops in an area of Ecchu Province. At that time, his troops also fought with those of Kazumasu TAKIGAWA who invaded Echigo from Maebashi-jo Castle in Kozuke Province, and managed to successfully defend Sakato-jo Castle.

In 1598, Kagekatsu's territory was changed to the Aizu area of Mutsu Province, and Hideharu HORI moved to Echigo from Echizen Province. Then Naoyori HORI, a vassal of Hideyoshi, became the lord of Sakato-jo Castle, making the Ueda area with a rice production of 30 thousand Koku (1 koku is approximately 10 liters) his territory. Naoyori modified Sakato-jo Castle, centering on the residential part at the foot of the mountain, so that the castle became of the style of early-modern times.

Sakato-jo Castle was demolished after Naoyori HORI was moved to Iiyama in Shinano Province in 1610.

Location and Territory.

As described above, in the Muromachi Period Sakato was a strategic site as regards transport and the economy. In addition, since both Echigo Province and Kozuke Province were, at that period, under the control of the Yamauchi Uesugi family, who were Kanto Kanrei (shogunal deputy for the Kanto region), traffic between Echigo and Kanto was frequent. Furthermore, Ueda Ginzan Silver Mine in the Uonuma area produced the largest amount of silver in Echizo at that time. These factors meant that, entering the Sengoku Period (Period of Warring States), furious battles occurred targeting the capture of this area.

Sakato-jo Castle was located on Sakato-yama Mountain which commanded a view of the Mikuni-kaido road across the Uono-gawa River, and was a strategic military site. Sakato-yama Mountain, with a height in excess of 400 meters from its base, protrudes like a peninsula towards the place where the Uono-gawa River and the Mikuni-gawa River, both of which flow through the Muikamachi basin, meet. Its north, east and west sides are steep cliffs, and the Uono-gawa River flowing at the west-side of the mountain constitutes a natural moat, providing a military defense line.

The slightly sloping area at the western foot of the mountain contains the remnants of the lord's residence and those of the residences of the vassals. The remains of the lord's residence are rectangular, 110 meters in the east-west direction and 80 meters in the north-south direction, and the residential area was surrounded by earthworks. In particular, an approximately 2-meter high stone wall on the western front side remains in good condition. There are remains of a moat called "Umeta" (literally, buried paddy field) between the front side of the remains of the residences of vassals and the Uono-gawa River.

A section called "Naka-yashiki" (literally, middle residence) remains, with a length of approximately 40 meters in the east-west direction and approximately 50 meters in the north-south direction, exists in the middle of a ridge called "Yakushi-one" (Yakushi ridge) to the south of the remains of the lord's residence. In addition, the remains of the "Kami-yashiki" (literally, upper residence), with a long and narrow shape, 30 meters long in the east-west direction and 120 meters in the north-south direction, exist in the so-called "Momonoki-daira" (literally, peach tree plain), which can be reached by climbing up Ootemichi (the road to the main gate to the castle) towards the mountain ridge, to the east of the remains of the lord's residence.

The Honmaru (the keep of the castle), which was located near the top of Sakato-yama Mountain and was used in battles, was constructed on a flat area at 634 meters above sea level.
Although not being located in such a high place, the Honmaru is supposed to have had a high military value because spring water was available even at the height of 7 go-me (70% of the height of the mountain)

Remains of some of the main buildings, called "Ninomaru" (the second fortress tower) and "Sannomaru" (the third fortress tower), exist on the ridge extending to the north from the "Honmaru." In addition, the remains of some buildings are also visible to the back-gate side to the southeast of the "Honmaru." An area of flat land called "Tsumenomaru" exists in a place 631 meters above sea level at the tip of the southeast ridge, and earthwork remains can be found there.

Large-scale trenches are seen at strategic points on the mountain ridge, and remains of stone walls exist on the east-side slope of the "Honmaru." In addition, remains of the "Nishinomaru" (the west-side fortress tower) can be found at a height of 500 meters above sea level on the ridge extending from the mountain peak to the southwest. More than 100 unejo tatebori (a series of parallel trenches running up the sides of the mountain) were constructed over approximately 2 kilometers from the "Nishinomaru" to the "Demaru" (a fortress tower built far from the main castle) at Teragahana, the tip of the ridge.

Information about the surrounding areas

At the foot of Sakato-yama Mountain, the grave of Masakage NAGAO and a monument commemorating the birth of Kagekatsu UESUGI and Kanetsugu NAOE are located. Fuji Gongen Shrine, which was said to have been built in 1586 through Kanjo (praying for the coming of a deity) by Kanetsugu NAOE, is located at the top of the mountain. Today, there are good roads for climbing Sakato-yama Mountain, and many hikers visit. A ceremony announcing the start of the climbing season is held on June 30 every year.

The vast areas around the foot of Sakato-yama Mountain have now become hot-spring districts and urban areas of the former Muikamachi Town.

Location and Access

Sakado, Muika-machi, Minamiuonuma City, Niigata Prefecture
Kanetsu Expressway
- About ten minutes by car from the Muikamachi interchange
East Japan Railway Company (JR East)
- Joetsu Line
- About five minutes by car from Muikamiachi station

[Original Japanese]