-Fortress spreads from hilltop to hillside like "A" letter-
Name: Shigiyama castle (Shigiyama-jyo)
Place: Tajima MInamiaizu town, Fukushima
Type: Mountain Castle
Built: Originally in 14th century, expanded in 16th century
Remaining remnants: Stone walls, clay walls and moats
Shigiyama castle (鴫山城) is located from hilltop to hillside of Atagoyama mountain, one of about 150 meter high from hillside in Tajima area of Minamiaizu town. Tajima area places about 40 kilometer South-southwest from Aizu Wakamatsu city, and is a town located in the valley of the upstream of Aga-gawa river (Aganogawa river), which flows northward to Aizu Basin area and turned to westward toward Sea of Japan.
The main route from Tokyo to Tohoku region passes Utsunomiya city, Shirakawa city, Koriyama city and Nihonmatsu city at 50 kilometer east of Aizu basin, and Aizu area is apart from this main artery. But there is another north and southbound route from Aizu Wakamtsu city to Utsunomiya city, which go up the valley of Agagawa river and passes tough path toward Nikko area. This route is called as Nishi Aizu Kaido road, and Tajima area is an important connecting point of this route with east and westbound route toward Shirakawa city or Tadami area.
Origin of Shigiyama castle
Precise year is unknown but Shigiyama castle might be built in 14th century by Naganuma clan. Naganuma clan was a branch family of Oyama clan, which was a traditional samurai clan originally lived at Nasu area of Tochigi prefecture. Naganuma clan at first lived at Naganuma castle (Fukushima prefecture) at current Sukagawa city, but later achieved Tajima area as their territory, and grew their power and became one of major local lords in the south part of Aizu area.
Since the beginning of 16th century, Ashina clan which held Aizu basin at Kurokawa castle (current Aizu Wakamatsu castle) succeeded to unite their family and became a warlord. Ashina clan allied with surrounding warlord such as Date clan and Souma clan, and aggressively expanded their territory toward east and south. At the time of Moriuji Ashina (1521-1582), utilizing internal conflict of Date clan, Moriuji left Date clan and became a large lord having most part of South half of current Fukushima prefecture.
Before the pressure of Ashina clan, Naganuma clan subordinated to Ashina clan and became their retainer around 1560. Under Ashina clan, Naganuma clan was treated as the leader of south part of Aizu region, and Shigiyama castle also became an important base of this area. Originally only hilltop area was used as a castle, but Naganuma clan added residential area at hillside area.
Transition of holders
But the glory of Ashina clan did not continue long. Aggressive military campaign exhausted the power of the clan, and as Moriuji lost his real son in ill, Ashina clan had to adopt their leader from other clan. This evoked internal conflicts between retainers after the death of Moriuji, and the power of Ashina clan rapidly declined.
On the other hand, Date clan at last overcame the effect of its former internal conflict and started expansion again. Although Date clan lost their leader Terumune Date (1543-1585) by assassination of Nikaido clan, his successor Masamune Date (1567-1636) further accelerated attack to surrounding warlords. Because of counter attack by surrounding warlords Masamune was forced into severe situation several times, but after struggle and beat all enemies. In 1589, Masamune beat Ashina clan at decisive battle of Suriagehara, and Ashina clan ruined.
At the time of the fall of Ashina clan, Naganuma clan quickly connected to Date clan and could survive as a general of Date clan. But in 1591, Date clan was transferred from Aizu area to Sendai area central ruler Hideyoshi Toyotomi (1537-1598), as a punishment for an agitation of rebellion by local lords. Naganuma clan also left Shigiyama castle, and this castle became the base of Ujisato Gamo (1556-1595) which became the lord of Aizu region.
Expansion by Gamo clan and Uesugi clan
Gamo territory was large area divided by mountains and held many unsatisfied former retainer of Ashina clan everywhere. Furthermore, Hideyoshi expected Ujisato to restrain Masamune Date, and also Ieyasu Tokugawa (1543-1616) who was the largest lord at Kanto region. To cope with internal rebellions and battle with other warlords, Ujisato reformed many local castles to use branch base with modern elements such as combined gate or stone walls. Shigiyama castle was also reformed by Gamo clan, and stone walls was built at the entrance to hilltop area. But remaining stone wall is not so high, and it might be a decorative one rather than actual combat purpose.
In 1595, Ujisato died in ill before 40 years old. Hideyoshi changed Gamo clan to Kagekatsu Uesugi (1556-1623), who was an adopted son of famous warlord Kenshin Uesugi (1530-1578) and lord of Echigo province (Niigata prefecture), continuously as a restraint against Ieyasu Tokugawa. As expected, when Hideyoshi died in ill in 1598, Ieyasu started their action toward next hegemony, the made false accusation against Kagekatsu Uesugi and started campaign by the name of grand minister of Toyotomi government.
In response to this situation, Uesugi clan decided to resist against Ieyasu. Kanetsugu Naoe (1560-1619), the chancellor of Uesugi clan, was close to Mitsunari Ishida (1560-1600), the chief magistrate of Toyotomi government who tried to stop the takeover of Ieyasu. Also, Uesugi clan might hope to be the independent power which held east part of Japan. Anyway Uesugi clan prepared for the battle, summoned unemployed commanders and soldiers, and reform border castles.
Structure of Shigiyama castle
As Utsunomiya area ahead of Shigiyama castle was Tokugawa territory, Shigiyama castle was an important base against Tokugawa clan. Uesugi clan planned to counterattack Tokugawa army around Shirakawa area, but there might be a risk of direct attack toward their main base Aizu Wakamatsu castle by detachment force when Uesugi clan sent all force to Shirakawa area. It was necessary to stand the attack of large army to certain period at Shigiyama castle.
Seen from front side, Atagoyama mountain has two ridges spread from its hilltop area to hillside like a tong. Uesugi clan processed these ridges as a wall and path to use defense lines. Especially, at the lower part of these ridges where enemy's attack is expected, dry moat and another clay wall were added to main wall.
At the slope between these two ridges, many terraces used for the residence of the commanders and soldiers were built. A line of dry moat and clay wall was built at the middle of the slope, which had a main gate of the castle protected by barrack gate over stone walls. Outside of this line, external barrier was also built connecting two tips of the ridge. This external barrier also consist of clay wall and dry moat, being folded to shot the enemy from side. Finally, Shigiyama castle became a large fortress consisted of hilltop fortress, two climbing down ridges and horizontal defense line, like "A" letter.
Afterward of castle
In 1600 Ieyasu and supporting lords marched toward Aizu region, but Mitsunari raised his army utilizing the absence of Ieyasu then Ieyasu turned his army toward west then Shigiyama castle was not involved into actual battle. Ieyasu beat Mitsunari at the decisive battle of Sekigahara, then in the postwar process Uesugi clan lost Aizu region and Gamo clan came back to Aizu area. But in 1616 because of Ikkoku Ichijo Rei (one domain one castle rule), Shigiyama castle was abolished along with other branch castles of Gamo clan.
Now all building was lost, but shape of castles well remain both at hilltop area and hillside area. Especially preservation of hillside terrace and outer barrier is valuable, as these area usually disappears by development in other castle. Also stone wall basement of main gate was restored, which indicated an existence of magnificent gate. When we look up a corned shape mountain wholly protected by many barriers, it shows solid will of Uesugi clan to protect strong enemy at this place by any means.
15 minutes walk from Aizu-Tetsudo line Aizu-Tajima station to hillside entrance. 60 minutes drive from Tohoku-Jidoshado Expressway Shirakawa interchange. 45 minutes walk from hillside entrance to hilltop castle.
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