-Prototype and mass production model-
Name: Naganuma castle (Naganuma-jo)
Alias: Chiyo-jo (Chiyo castle), Gagyu-jo (Gagyu castle)
Place: Naganuma Sukagawa city, Fukushima
Type: Hill Castle
Built: 14th century?
Remaining remnants: Stone walls, clay walls and moats
Naganuma castle (長沼城) is located over Hidakami-yama mountain, a peninsular like hill of 40 meter height spreads from Taishaku mountains toward Koriyama basin, at the center of former Naganuma town. Naganuma town is a small and quiet valley formed by Ebana-gawa river and Sunoko-gawa river at the western edge of Koriyama basin, in the western part of current Sukagawa city.
Naganuma area had been an important point of communication where roads from Aizu Wakamatsu basin passing Seisido-Toge pass, current Aizu Tajima area which is the center of vast area of South Aizu area, Sukagawa area where is connected to north part and east part of Fukushima prefecture, and Shirakawa area that is the entrance of Tohoku region from Kanto region. Because of this geographical condition, this place was an important place for the holder of Aizu Wakamatsu basin both for offence and defense.
Origin of Naganuma castle
Precise year is unknown but Naganuma castle might be built by Naganuma clan originally as their main base. 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 later achieved Tajima area as their territory, and grew their power then became one of major local lords in the south part of Aizu area. In the middle of 15th century, Naganuma clan moved their main base to Shigiyama castle at captured Aizu Tajima area but kept Naganuma castle as their major branch castle.
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.
Conflicts between Ashina clan and Date clan
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. Around this time Naganuma castle might work as a front base of Ashina clan to advance into the valley of Abukuma-gawa river called as Nakadori area.
However, 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.
Transition of holders
Because of counter attack by surrounding warlords such as Mogami clan, Soma clan or Satake clan Masamune was forced into severe situation several times, but after struggle Masamune beat all enemies. In 1589, Date army beat Ashina clan at decisive battle of Suriagehara, captured Aizu Wakamatsu castle which was the main base of Ashina clan then Ashina clan ended its history as a warlord.
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 by central ruler Hideyoshi Toyotomi (1537-1598), as a punishment for an agitation of rebellion by local lords. Along with neighbor castles, Naganuma castle became the base of Ujisato Gamo (1556-1595) who became the lord of Aizu region.
Ujisato Gamo was a talented lord praised by Hideyoshi or former ruler Nobunaga Oda (1534-1582) and promoted into large warlord, but had to reign the vast territory separated by mountains and snows. There were many former retainers of Ashina clan or Date clan not satisfied with this situations, and Gamo army was just scratched with promotion.
Mass production model built under limitation
Under such situation, other than his main base Aizu Wakamatsu castle, Ujisato reformed or built about 15 branch castles all over the territory. But it was necessary to complete the construction as soon as possible, with limited manpower and materials. To spare the time of planning, Ujisato chose hill castles as long as possible and used common planning equivalent to his former main base Matsusaka castle.
Matsusaka castle is a brilliant hill castle which places terraces all over the round shaped hill, and connected the route in spiral shape. Round shape needs minimum soldiers to defend all direction, and spiral shaped roads passing several terraces to reach to central area made it possible to gain time at the time of enemy attack.
Ujisato used Matsusaka castle as a prototype model, and brought similar plan to many branch castles such as Naganuma castle, Miharu castle, Inawashiro castle, Nihonmatsu castle (Fukushima prefecture), Nakayama castle (Yamagata castle), or Shiroishi castle (Miyagi prefecture) as a mass production model.
Of course Matsusaka castle is a splendid castle wholly covered by stone walls as a main base, and Ujisato could not built stone walls at all part of these branch castles then these castles are mainly protected by clay walls. Stone walls are partially used around the main gate, both for the purpose of strengthening the structure and showing the authority.
Structure of Naganuma castle
Central area of Naganuma castle is a pentagon shaped area of 70 meter long and 50 meter wide, which has a basement of main building covered by stone walls at its western edge. At the west of central area there is a oblong style area of 50 meter long which has a stone wall at its south side, and there is another long and narrow area at the east. These three areas at the top of the hill might be the original area constructed by Naganuma clan or Ashina clan.
Surrounding these core areas, several terraces of about 40 meter long square are built at the halfway of the hill. These areas are connected by small masugata buffer area, which is the element of modern castle even though formed by clay walls. As western part is connected to backside mountains, this side is protected by deep and wide dry moat of 20 meter wide. Total size of above hill area is about 250 meter long and 100 meter wide, a moderate size as a branch castle.
At the east of the hill where is not protected by marsh, there was a line of f outer barrier between two rivers. Even though losing most part, but line of clay wall and dry moat with a shape of gate remains over 300 meter in private property. The size of outer barrier is extremely large for a branch castle, and this shows the importance of Naganuma castle for Gamo clan.
Afterward of Naganuma castle
After the death of Ujisato, Kagekatsu Uesugi (1556-1623), the lord of Echigo province (Niigata prefecture) and an adopted son of famous warlord Kenshin Uesugi (1530-1578) was transferred to the former territory of Ujisato. Naganuma castle was used as a branch castle of Uesugi clan, and Kagekatsu placed his important retainer Tadanao Shimazu (?-1604) as a commander of Naganuma castle.
At the time of the battle of Sekigahara in 1600, Naganuma castle might be planned as an important point to control the front line to resist against overwhelming army of Ieyasu Tokugawa who once started to march toward Aizu region. But Ieyasu turned his army to central area on the march, and Naganuma castle was not involved in the battle. Uesugi clan lost Aizu basin as a result of the battle of Sekigahara, and Naganuma castle might be abolished under Ikkoku Ichijo Rei (one castle one domain rule) published in 1615.
Now all building was lost but structure of the castle well remains on the hill. Castle site becomes a park and fully covered by cherry blossom flower in spring. Moderate height eye catching hill with well formed terraces was originally appropriate for military purpose, but is also suitable as a park. Same as other same type branch castles of Gamo clan, Naganuma castle lost its function but still live as a symbol of the area.
30 minutes drive from Tohoku Jidoshado Expressway Sukagawa interchange.