Fukushima Castle (Mutsu) -Castle protected mysterious medieval port-

Fukushima Castle (Mutsu)

-Castle protected mysterious medieval port-

Overview

Name: Fukushima castle (Fukushima-jo)
Alias:
Place: Aiuchi Goshogawara city, Aomori

Location: 41.04778485205516, 140.36399381438014
Type: Flat Castle
Built: 10th century?
Remaining remnants: Clay walls and dry moats
Title:

Brief History

Fukushima castle (福島城) is built over the plateau spreads around north shore of Lake Jusan-ko, a large one of 5 kilometer long and 5 kilometer wide at the western coast of Tsugaru peninsula. Lake Jusan-ko is at the mouth of Iwaki-gawa river which forms Tsugaru basin, and connected to the Sea of Japan by narrow path.

Lake Jusan-ko is the third largest lake of Aomori prefecture and a large brackish lake along with Lake Hamana-ko or Lake Shinji-ko. This lake is gifted with rich fishery resources from sea water to mixed water and river water, especially for Shijimi Clams. Large nature marsh is used as a stopover point of birds such as swans, and also for marine activities.

The lake is separated from the Sea of Japan by two sandbanks. Especially the southern one is a large one of about 5 kilometer long and 500 meter wide, which is appropriate size to build a town. Furthermore, a long and narrow inlet spreads through the center of the bank, which works as a natural harbor along with the inner coast toward the lake. Because of this terrain and location as a stopping point toward Hokkaido island, there was a prosperous medieval port named Tosa-Minato at this point.

Origin of Fukushima castle

The origin of Fukushima castle is unknown but it might be originally built in 10th century. Around this time the effect of Yamato dynasty reached to the north edge of mainland, and traditional indigenous society faced significant change. Around this time fortified villages were built around the area.

Fukushima castle might be the largest one of such fort, having the size of about 60 meter long square. This castle is built utilizing the edge of peninsular like height which is sandwiched by Lake Jusan-ko and Aiuchi-gawa river. Interestingly several element of Fukushima castle such as square shape or linear line of clay wall resembles to ancient castles of Yamato Dynasty, such as Tagajo castle (Miyagi prefecture) or Akita castle (Akita prefecture).

In 11th century, after the campaign of Zen-Kunen (former nine years) and Go-Sannen (latter three years), Oshu Fujiwara clan seized whole part of current Tohoku region and became semi-independent power. The prosperity of Oshu Fujiwara clan was supported by the gold and horses produced in the territory, and also naval trades with Hokkaido Island or the continent.

Rise of Ando clan

According to the investigation, Tosa-Minato port already worked as a trade port at the time of Oshu Fujiwara clan, and Fukushima castle might work as a managing office of the port. At the fall of Oshu Fujiwara clan, Yasuhira Fujiwara (1155-1189), the last leader of the clan, disposed their main base Hiraizumi city and headed northward probably for Tosa-Minato port, to move to Hokkaido island. But on the way Yasuhira was killed by betrayal of their general.

After the fall of Oshu Fujiwara clan, Kamakura Shogunate appointed Ando clan as the lord of Tsugaru peninsula and Hokkaido island. Origin of Ando clan is unknown but it is said as a descendant of indigenous people of Tohoku region. It is said that Ando clan was a leader of sea clan which engaged in fishery and marine transportation around Tohoku region and south part of Hokkaido island. But as a naval clan they were not so stick to the land then the record of Ando clan is quite limited.

Originally Ando clan lived at the south half of Tsugaru plain, but at the end of Kamakura era, large internal conflict of Ando clan correlating with the rebellion of local people occurred. After this conflict Ando clan became a centralized family and moved their main base to Fukushima castle. to focus on marine trade.

Structure of Fukushima castle

Fukushima castle spreads over roughly 600 meter long square shaped plateau faces the lake. The east edge of the castle area is separated from outside by valley and only connected by 100 meter long narrow path. At this path the linear line of clay wall and dry moat was built to prevent entrance of the enemy.

The central area of the castle is a square shaped area of 200 meter long, being surrounded by clay wall and water moat. This part is a typical residence of samurai during Kamakura era and Muromachi era, and actually the remnant of medieval residence was found at this area. This area might be used as the ground for the residence of Ando clan.

Fukushima castle basically relies its defense on natural terrain, but narrow projections at the northwest and southwest of the castle which might be used as an approach line were shut by line of clay wall and dry moat. Main gate of the castle was built at the middle of the line of clay wall at eastern edge, which has folded clay line and buffer zone.

Around the central area, there might be residence of branch families and retainers. At the south of central area there is a ruin of clay wall like a fence of the road to the valley connected to the lake, and this might be a direct gate from the lake. Even though having not so mach artificial structures, the size of the castle matches as the main base of Ando clan.

Prosperity of northernmost trade port

At the same time, Tosa-Minato port also enjoyed its peak period under Ando clan. According to investigation, the size of Tosa-Minato town reached to 1.5 kilometer long and 500 meter wide. Port area was divided by the line of clay wall and water moat slightly remaining at the south of school ground, which separated the town into north half and south half.

The north half was the public space, including the residence of Ando clan at current school ground, residence of retainers, shrines and port equipments. Contrary to this, south half was a private area including residences of merchants, warehouses and fisheries. At the south edge of the town temples were built as front forts, and at the side of water lane Minato shrine was built both for pray of safety and lighthouse.

Tosa-Minato port was regarded as one of the major port in the medieval era, equivalent to Hakata port. This port engaged in triangle trade between Honshu main land, Hokkaido island and the continent. Ando clan processed planned expansion of the town, and remnants of the town were placed clearly at the both side of main street. Ando clan engaged wide area naval trade toward central and western Japan.

Sudden fall of port and clan

However, the prosperity of Ando clan and Tosa-Minato port was gradually threaten. Strict foreign policy of the continent limited foreign trade, and progress of navigation increased competition of the area. Furthermore, conflict of the South Court army and Muromachi Shogunate army at Tohoku region which gave freedom to Ando clan ceased by the end of 14th century.

In the beginning of 15th century, Nanbu clan which governed Pacific Ocean side of current Aomori prefecture rapidly grew and started expansion toward west. At first the leader of Ushiogata Ando clan, the branch family of Ando clan, married with the princess of Nanbu clan, to keep peace with Nanbu clan.

However, around 1430 and 1440, Ando clan suffered severe defeat before Nanbu clan and abandoned Fukushima castle and Tosa-Minato port. Yoshisue Ando (?-1453), the leader of the clan, once retreated to Hokkaido island where Ando clan held influence and raised his army to retrieve their territory, but this raise failed then Yoshisue lost his live.

Survival after trouble and afterward

The history of original Ando clan had ended at this time. Tosa-Minato port was destructed among this battle and once reconstructed, but Nanbu clan was not so interested in foreign trade and concentrated to the expansion at Pacific Ocean side, thus Tosa-Minato port had once disappeared.

However, Ando clan and Tosa-Minato port recovered from critical situation. A branch family of Ando clan became the lord of Hiyama castle at Dewa province (Akita prefecture), and merged with their branch family at current Akita city then finally continued as a feudal lord of Miharu castle (Fukushima prefecture).

Tosa-Minato port was severely damaged by piled mud, but after the establishment of Edo Shogunate and Tsugaru domain it was restored as loading port of rice harvested along Iwaki-gawa river, and also as a stopping point of Kitamae-Bune trade ships which navigated along the coast of the Sea of Japan toward Hokkaido Island.

After the Meiji revolution, Tosa-Minato port could not work because of its shallow depth for modern ships and arrival of railways. Different from other major naval port which continues until now, Tosa-Minato port lost its appearance but remnants are kept in the ground. Investigation of Tosa-Minato port and Fukushima castle revealed the history of Ando clan as a wide area trader of marginal area, which was not fully written on papers.