Shirotori-tate Castle

-Castle looked endless stream of Kitakami-gawa river-

Overview

Name: Shirotori-tate Castle (Shirotori-tate)
Alias:
Place: Maesawa-Shirotoritate Oshu city, Iwate

Location: 39.02494982006589, 141.13412647980945
Type: Hill Castle
Built: 10th century?
Remaining remnants: Clay walls and dry moats
Title:

Brief History

Shirotoritate castle (白鳥館) is located over a small hill where Kitakami-gawa river curves like “S” latter at the south edge of current Oshu city. At castle site Kitakami-gawa river is surrounded by plateau of both side only 500 meter apart, and flows at narrow space between the hill and plateau.

Formerly the stream of Kitakami-gawa river straightly flowed at the east edge of the castle, but due to flood the main stream moved to the flow of Shirotori-gawa river thus it became current “S” letter shape. Even before the movement of flow it has been an important point to watch the river and load items to the ship.

Flow of Kitakami-gawa river

Kitakami-gawa river flows 250 kilometer straightly from north part of current Iwate prefecture to Ishinomaki bay of current Miyagi prefecture. The river has many tributaries at both side like a tree, and forms Kitakami plain that is a major flat area of Iwate prefecture and artery between Sendai area and Aomori or Hokkaido area.

Relatively slow stream and abundant water of Kitakami-gawa river was ideal for river transportation. Commercial river transportation prospered from the river reform at the beginning of Edo era to arrival of railway, but small transportation has been performed since the ancient era.

In 9th century, Tamuramaro Sakanoue (758-811), the general of Yamato dynasty, entered into Kitakami basin and expanded the territory of the dynasty toward north. At this time ancient castles such as Isawa castle, Shiwa castle or Tokutami castle (Iwate prefecture) were built at the side of Kitakami-gawa river, and transportation of soldiers and supplies might be performed by river transportation.

Rise of Abe clan

In 10th century, Abe clan which might be the local lords emerged from residents grew their power toward whole part of Kitakami basin. Abe clan held their main base Koromogawa-saku at the side of Koromogawa river and about 3 kilometer northwest of Hiraizumi area.

Koromogawa area is at the south edge of Kitakami basin and connected to Sendai area by road and river. Probably Abe clan acted as the representative of central government to local residents, and also representative of local residents to central government. Main base at the edge toward central government was an ideal place to act so, by controlling the communication between the central government and Kitakami basin.

At this time, Shirotoritate castle might work as a river fort to protect the main base of Abe clan at the valley of Koromogawa river, along with Takadate hill that is famous for the place Yoshitsune Minamoto (1159-1189), the younger brother of Yoritomo Minamoto (1147-1199) died. Considering the importance of the castle, relative of Abe clan was placed at Shirotoritate castle.

Former nine year battle and fall of Abe clan

Abe clan prospered in the former half of 11th century and became semi-independent power. As Abe clan became declined to pay taxes to the central government, then Yoriyoshi Minamoto (988-1075), the military noble and leader of Minamoto clan, was sent to Oshu region to subjugate Abe clan.

Abe clan once followed to Yoriyoshi Minamoto, but accidentally the battle between Abe clan and Minamoto clan named as “Zen-Kunen no Eki (former nine years battle) occurred. Sadato Abe (1019-1062), the leader of Abe clan, once broke the army of Minamoto clan at the battle of Kinomi then the army of central government was pushed put from Kitakami basin.

But Yoriyoshi Minamoto turned Kiyohara clan which held Yokote basin of Akita prefecture under Abe clan to central government, and made two front battles toward Abe clan. Outnumbered Abe clan left Koromogawa-saku and moved to Kuriyagawa-saku at the west of current Morioka city central, but was ruined by the army of Minamoto clan.

Later three year battle and Oshu Fujiwara clan

Replacing, Kiyohara clan held the former territory of Abe clan and seized Kitakami basin. Kiyohara clan followed central government and became a noble, but later internal conflict for successor occurred. Kiyohira Fujiwara (1056-1128), who was the son of the woman of Abe clan but became a step son of Kiyohara clan, allied with Yoshiie Minamoto (1039-1106), the son of Yoriyoshi Minamoto, and ruined his opponents at the battle of Go-Sannen (later battle of three years).

Kiyohira Fujiwara became the ruler of Kitakami basin and established Oshu Fujiwara clan. Oshu Fujiwara clan placed their main base at Hiraizumi area, just at 2 kilometer south of Koromogawa-saku of Abe clan. Oshu Fujiwara clan prospered at Kitakami basin for 100 years based on gold mine and foreign trade, and spectacular culture based on Buddhism bloomed at its main base Hiraizumi town.

As Hiraizumi town was only 4 kilometer apart from Shirotoritate castle, the castle might be used as the watching point of Kitakami-gawa river by Oshu Fujiwara clan. Same as Abe clan Oshu Fujiwara clan held castles around Kitakami basin, and Shirotoritate castle might be kept as a river fort to protect Hiraizumi area.

Shirotoritate castle in medieval era

In 1189, Oshu Fujiwara clan was ruined by Yoritomo Minamoto, the founder of Kamakura Shogunate who ruined Taira clan at the battle of Dannoura. Kamakura Shogunate appointed their retainer Kasai clan as the general governor of Tohoku region, then Kasai clan once entered into Hiraizumi area but soon moved to Ishinomaki area at the side of Pacific Ocean.

After the fall of Kamakura Shogunate in 1333, there around conflict between Muromachi Shogunate and the South Court all around Japan. As Akiie Kitabatake (1318-1338), a brilliant general of the South Court stayed at Tagajo castle (Miyagi prefecture) as the commander of Tohoku region, there arouse tension between the South Court army and Kasai clan belonged to Muromachi Shogunate.

The north edge of the territory of Kasai clan might be Mizusawa area of current Oshu city, and site of Shirotoritate castle is an important place for Kasai clan to connect their main territory moved to Tome area at downstream of Kitakami-gawa river and their front at Mizusawa area. Shirotoritate castle might be reformed into medieval castle at this time.

Structure of Shirotoritate castle

Shirotoritate castle spreads over narrow hill curved like a hook, which is about 20 meter height from hillside and river. Central area of the castle is a triangle shaped one of about 50 meter long, which might lose its north half when the flow of Kitakami-gawa river changed. South edge of central area is protected by dry moat which is about 5 meter wide.

Secondary area at the south of central area is an oblong shaped one of about 120 meter long and 40 meter wide, which has gates at the middle of east line and southwestern corner and line of clay wall at its west line. Considering large size of the area, it might be used as the ground for the residence of the lord.

At the east of central area and secondary area, there are layers of terraces toward the river. These terraces might be used as the merchant town, storage or trading place attached to the river port of Kitakami-gawa river. Opposite side at the west is the defense line of the castle then this part is protected by sheer slope of clay wall.

At the south of core areas, third area or fourth area both are about 150 meter long and 70 meter wide stands along with the shape of the height. The shape of terraces might be changed by development, but they still keep the line of clay wall and entrance then they might be the part of the castle.

Total size of the castle is over 500 meter long and large one at the area. Common structure of the castle, which consists of same size large terraces and the superiority between terraces is not clear, is common to other medieval castle in the north half of Tohoku region. But it has additionally has the character of river side castle.

Afterward of castle

By the end of 14th century, the power of the South Court disappeared from Tohoku region. The power of Kasai clan was not so strong but it kept current Mizusawa area at the north of castle site as north border. It is not so necessary for Kasai clan to transport materials by Kitakami-gawa river compared with Abe clan or Oshu Fujiwara clan, Shirotoritate castle lost the character as the castle in 15th century and turned to river side town.

Now major part of the castle is used as the ground of houses or agricultural fields, but the shape of terraces are generally kept except for its north edge. From the north edge of the castle endless stream of Kitakami-gawa river is well seen. As there is not so many record on this castle the actual situation of the castle is not clear, but it is easily imaginable that many ships going up and down the river are well seen from castle site.