Tokutanjo Castle

-From castles of nation to forts of local power (3)-

Overview

Name: Tokutanjo Castle (Tokutanjo)
Alias:
Place: Nishitokutan Yahaba town, Iwate
Type: Flat Castle
Built: 811
Remaining remnants: Clay walls and dry moats
Title:

Brief History

Tokutanjo castle (徳丹城) is located over the flat area between Kitakami-gawa river and current Yahaba town at 15 kilometer southward from Morioka city central. Route 4, an artery of Tohoku region which connects Sendai city and Aomori city runs west half of the ruin thus inner part of the castle existed at the east of the road but west side wall locates opposite of the road.

Tokutanjo castle exists at the edge of low height plateau spreads eastward from Yahaba station. As this plateau is surrounded by wetlands do not need irrigation, this area had been developed for rice cultivation since ancient era, which is shown by ruins of Jomon era and Ezomori old tombs.

Process of operation at Kitakami basin

Tokutanjo castle was built in 811, under application of Watamaro Funya (765-823), the regional commander of Imperial Household at Kitakami basin. In the end of 8th century, under the command of Tamuramaro Sakanoue (758-811), the predecessor of Watamaro Funya, the Imperial Household army entered into Kitakami basin and built Isawajo castle (Iwate prefecture) in 802 to secure south half of the basin.

Next year Tamuramaro Sakanoue marched to the north half of Kitakami basin and built Shiwajo castle (Iwate prefecture). Shiwajo castle was a huge castle of 840 meter long square, which was equivalent to Tagajo castle (Miyagi prefecture) that was Japanese eastern vice capital at that era. Based on Shiwajo castle, Tamuramaro prepared for next campaign toward north.

However in 805, considering the burden of people, there was a discuss on good government at the cabinet. A minister insisted people suffered from military operation at Tohoku region and construction of Heiankyo capital, then Emperor Kanmu (737-806) accepted this opinion then decided to the suspension of military operation and capital construction.

Build of Tokutanjo castle

After the death of Emperor Kanmu, next Emperor Saga (786-842) , Tamuramaro Sakanoue was appointed as a high rank minister then Watamaro Funya once served to Tamuramaro and was familiar to the situation of Kitakami basin succeeded the role of Tamuramaro Sakanoue.

In 811, Watamaro Funya started last operation of Imperial Household army at Kitakami basin. Watamaro marched to current Ninohe area and Hei area from Kitakami basin and seized both areas. Watamaro reported the completion of his operation and decrease of troops to the cabinet and was approved.

Considering this situation, Shiwajo castle was too large and expensive only for maintaining securities. Watamaro applied to abolish Shiwajo castle due to the damage by flood and newly build Tokutanjo castle. The flood might be an excuse of abolition of Shiwajo castle considering the fame of Tamuramaro Sakanoue and it might be a restructuring of army and castles.

Structure of Tokutan castle

The size of Tokutanjo castle is about 350 meter long square and less than half of Shiwajo castle. It is a clear square shape but forcibly built over smaller trapezoid shaped plateau, thus southwestern corner and southeastern corner exceeded the edge of plateau and were built at the marsh.

North line which was on the plateau is securely protected by combination of pressed clay wall and dry moat like Isawajo castle or Shiwajo castle, but other three directions faces the marsh was secured by wooden fences, due to weak ground and decrease of construction costs. Gates were built at the middle of each direction and south gate might be the main gate of the castle.

At the center of the castle, there is a inner area of 80 meter long square which had main hall and two sub halls which might be used for ceremony or meetings. Inner area might be encircled by pressed clay wall and have four gates at each direction. Surrounding inner area there might be administrative offices or storages along with grid street, and because of limited size there was no place for the camp of soldiers like Isawajo castle or Shiwajo castle.

Cease of operation

At the east of central area, there was a remnant of precedent local administrative office. Probably there might be a providential office or river port office before the construction of the castle, and Tokutanjo castle might be built utilizing such precedent office. From this part a canal to Kitakami-gawa river was built, to transport supply and soldiers from the river.

After the completion of Tokutanjo castle, 500 soldiers stationed at Tokutanjo castle for four years, But due to fiscal problem, the post of central troop was abolished both at Tokutanjo castle and Isawa castle in 815. Based on remnants Tokutanjo castle might be used by the middle of 9th century or beginning of 10th century, as an administrative office and base of local troop.

Finally Tokutanjo castle became not used and was abolished, then the remnant was covered by soil and disappeared. As the record of Tokutanjo castle is quite limited and only shows its existence, the location of the castle was a mystery. After World War 2, the remnant of wooden pillars were found by cultivation and development, and as a result of excavation the remnants of fences and gate were found and identified as the remnant of Tokutanjo castle.

Afterward of castle

Now no remnants remain on the terrain but former shape of Tokutanjo castle is gradually revealed by the process of prospection. As the castle was disposed after short term use and covered by soil, items such as wooden helmet, earthenware or stoneware were found and compliments limited literary records of the castle.

Now westward of Route 4 is under the process of park improvement and the location of fences and gates are expressed at the ground. Eastward of Route 4 also shows the location of inner area but not so maintained. The size of Tokutanjo castle is clearly smaller than Isawajo castle or Shiwajo castle and the structure becomes simple, then this shows the end of strong national operation and rise of local powers.