Saturday, May 21, 2016

Sannohe Castle -Sailing ship shaped castle survived heavy storm-

Sannohe Castle

-Sailing ship shaped castle survived heavy storm-



Name: Sannohe castle (Sannohe-jo)
Place: Umenai Sannohe town, Aomori
Location: 40.38196451117189, 141.26554250309076
Type: Hill Castle
Built: 1539
Remaining remnants: Gate (moved), stone walls, clay walls and dry moats 

Brief History

Sannohe castle (三戸城) is located on Shiroyama hill, a long and narrow one of about 70 meter height from hillside at the center of Sannohe town. Sannohe town is a one at the meeting point of Mabechigawa river which flows northward from the northern edge of Iwate prefecture toward Hachinohe city of Aomori prefecture, and its tributary Kumaharagawa river runs from the border of Aomori prefecture and Akita prefecture near Lake Tazawako.

Imporant path to Aomori area

Between the north edge of Kitakami basin where Morioka city locates and Hachinohe plain where Hachinohe city resides, a wide hill area spreads over 50 kilometer long. Roads connect these two areas runs along the valley of Mabechigawa river or its tributary Appigawa river to pass this hilly area. In ancient era, Yamato dynasty advanced into this area posted nine garrisons around this area along with Mabechigawa river, and the word "Sannohe" means third camp.

Since then, Sannohe area is used as an important connecting point of current Morioka area and Hachinohe area. Even now, Route 4 (Oshu Kaido road) and Tohoku Shinkansen line runs through Sannohe town. In addition to this, Sannohe area is also a meeting point of the roads from Tsugaru area which was the western half of Aomori prefecture or north part of Akita prefecture passes Oshu Sanmyaku mountains. Because of this geographic condition, Sannohe area has been an important point of communication and an appropriate area to build a main base.

Origin of horse breeding clan

Precise year is unknown but Sannohe castle was built by Harumasa Nanbu (1517-1582), the leader of Nanbu clan, in 1539. Nanbu clan was originally a branch family of Minamoto clan stem from Yoshimitsu Minamoto (1045-1127). In 12th century Yoshikiyo Minamoto (1075-1149) came to Kai province (Yamanashi prefecture) and named as Takeda clan, which later became the governor of Kai province and is known for famous warlord Shingen Takeda (1521-1573). 

Later Toomitsu Kagami (1143-1230), the grandson of Yoshikiyo, held the west edge of current Kofu basin, then his son Mitsuyuki Nanbu (1165-1236) was given Nanbu area along Fuji river by his loyalty for Yoritomo Minamoto (1147-1199), the founder of Kamakura Shogunate and Nanbu clan started. Nanbu area is a historical horse breeding area, and this fact strongly affected the character of Nanbu clan. 

When Yoritomo Minamoto destroyed Oshu Fujiwara clan which once dominated whole part of Tohoku region, Nukanobu county which spreads from north edge of Iwate prefecture to eastern half of Aomori prefecture including Sannohe area became the territory of Hojo clan, the house of chancellor of Kamakura Shogunate. Nanbu clan was close to this Hojo clan and might had relationship with Sannohe area from this time.

Northern general loyal to Emperor

At the fall of Kamakura Shogunate in 1333, Moroyuki Nanbu (?-1338), leader of Nejyo Nanbu clan, participated in anti-Shogunate army and activated at the siege of Kamakura city. After the fall of Shogunate, new government of Emperor Godaigo (1288-1339) appointed prince Norinaga (1328-1368, later Emperor Gomurakami) and  brilliant general Akiie Kitabatake (1318-1338) as a general commander of Tohoku region, then sent them to Tagajo castle in current Miyagi prefecture.

Moroyuki Nanbu accompanied them and was formally appointed as a governor of Nukanobu county, utilizing relationship to the area. As Nukanobu area is known for a place of good horse, and Emperor Godaigo expected Nanbu clan to bleed good horses by their skill for the Shogunate. Masayuki built Nejo castle as his main base and became the leader of Nejo Nanbu clan, and placed his relatives as magistrates over the territory. At this time, Nobunaga Nanbu was placed at Sannohe area and became the leader of Sannohe Nanbu clan.

Moroyuki suppressed rebellion of former Shogunate side lords around country, provided horses to the cavalry of Akiie and secured the backward  during Akiie's first expedition to Kyoto city against Muromachi Shogunate in 1335. Next Moroie accompanied with Akiie during his second expedition in 1337. Akiie and Moroie once broke Muromachi Shogunate army, but finally died at the battle of Ishizu in 1338. After the death of Moroie, his son still kept lone struggle against Muromachi Shogunate, but the situation became worse and worse.

Takeover of leader position

At this time, Masayuki Nanbu (1328-1388), son of Nobunaga Nanbu and leader of Sannohe Nanbu clan, faced the pressure of Muromachi Shogunate force at the border of Nanbu territory then changed to Shogunate side. Next his son Moriyuki Nanbu (1359-1437) coordinated Shogunate and Nejo Nanbu clan in the end of 14th century,  then whole Nanbu family subordinated to the Shogunate. From this time, Nejo Nanbu clan retreated to Nejo castle and Sannohe Nanbu clan became the leader of Nanbu clan. 

Sannone Nanbu clan which became the leader of Nanbu clan aggressively fought with surrounding lords such as Ando clan or Onodera clan and expanded into Tsugaru region or north part of Akita prefecture. But because of decentralized relatives and takeover of the leader, the clan sometimes fell into internal conflicts. In 1539, at the time of Harumasa Nanbu (1517-1592) because of the conflict between retainers, Shojyujidate residence which had been a main base of Nanbu clan was burnt and lost many documents inherited documents. Harumasa built Sannohe castle as his new main base.

Structure of Sannohe castle

Sannohe castle spreads over a ship shaped long and narrow hill of 500 meter long and 200 meter wide, faces northeast to southwest ward. This hill has a flat top and sheer wall, and being separated from backside hills by the erosion of two rivers, then it was an good place to build a castle.  

The flat surface of the hill was separated into about 20 areas. Central area of the castle is a large one of 100 meter long and 200 meter wide at the highest point of the hill, and residence of the lord was built at this area. There was a three story main turret at the middle of central area like a control tower of battleship, and the entrance of central area was a splendid one protected by stone wall.

Between the central area and main entrance from castle town at the southwest edge of the hill, residence of relatives and important retainers were orderly placed at both side of main road. Main gate of the castle named as "Tsuna Gomon" is a masugata style gate with folded path and securely protected by stone walls, as if it is a figure head of the ship. 

At the backside of central area, there were several flat terraces with ponds, being used for stable and station of soldiers. Backside gate of the castle named as "Kajiya Gomon" at northeast edge of the hill is also protected by a line of stone wall. Compared with the wall of front side gate, this one was built by rough stones and might be built in earlier period. Looking at the shape of the castle consist of flat terraces at slightly different levels, sharp shape of its front side gate and half round shaped clay wall at back side gate surely resembles to sailing ship.

Glory of northern lord

Harumasa achieved Sannohe castle as his flagship sailed into troubled water. Just after the rebellion of retainer, Harumasa travelled Kyoto city, the capital of Muromachi Shogunate, met the Shogun and got the authority to control the clan. Returned Harumasa suppressed the rebellion and stabled the situation, then turned to the external expansion. 

At this time Akita clan which was the lord of Akita area aimed at Kazuno area at the border of Akita prefecture and Iwate prefecture, but after a fierce battle Harumasa rejected the invasion of Akita clan. Harunobu also strengthened dominance at Tsugaru area and Kitakami height, and brought the peak period to Nanbu clan. At this time, Nanbu clan was praised that their territory was too wide and it was necessary to travel the time crescent moon changed to full moon to pass it. 

Arrival of turbulent storm

But Harumasa also brought a cause of trouble to the clan. As Harumasa did not have his son at first, thus Harumasa adopted his cousin Nobunao Nanbu (1546-1599) as his successor, but later had his own son Harutsugu Nanbu (1570-1582) and thought to expel Nobunao. Nobunao left Sannohe castle and was protected by Nejo Nanbu clan, and a quiet internal conflict occurred between Harumasa and Nobunao.

Furthermore, looking at this situation, Tamenobu Oura (1550-1608) who managed Tsugaru area under Nanbu clan suddenly rebelled, killed Takanobu Ishikawa (1495-1571) who was the commander of Nanbu clan, and captured that area. As Takanobu was the real father of Nobunao, Harunobu did not send army for Takanobu but finally this became a cause of lost of Tsugaru area. Under internal and external troubles, Harunobu died in ill in 1582. 

Harutsugu succeeded Harumasa but also died in accident soon and serious internal conflict between Nobunao Nanbu and Sanechika Kunohe (1542-1591), the husband of the daughter of Harumasa and younger brother of Masazane Kunohe (1536-1591), the military core of Nanbu clan. At the meeting held at Sannohe castle, Nobunao and his retainer Nobuchika Kita (1523-1613) organized other retainers thus Nobunao became next leader, but Kunohe clan strongly dissatisfied this result.

Disorder and restoration

In 1590, central ruler Hideyoshi Toyotomi (1537-1598) started Odawara campaign against Hojo clan which held Kanto region, and also ordered local lords of Tohoku region to subordinate. Nobunao already connected to Hideyoshi visited the camp and was formerly approved as the leader of Nanbu clan. But at this time Tamenobu Oura changed his surname to Tsugaru clan also visited Hideyoshi and was approved as the lord of Tsugaru area.

But next year, looking at rebellions of local lord against Toyotomi government, Masazane Kunohe raised his army against Nobunao. Nobunao could not extinguish Masazane by his army, and asked reinforcement to Hideyoshi. Being hurt his authority, Hideyoshi sent large force to Kunohe castle (Iwate prefecture), the main base of Kunohe clan, and suppressed the rebellion. At last, Nanbu clan finally fixed their situation as the lord under Toyotomi government.

After the cease of rebellion, Nobunao achieved middle part of Iwate prefecture, and moved his residence from Sannohe castle to Kunohe castle to govern the territory expanded toward south. But Sannohe castle was also kept as a major base of Nanbu clan, and reformed into a modern castle equipped turrets and stone walls. Further Nanbu clan newly built Morioka castle (Iwate prefecture) and moved there in 1634, then Sannohe castle was abolished but the ruin had been maintained as a original place of the clan.

Afterward of castle

Today all building except for one gate transferred to neighbor temple was lost, but structure of the castle well remains on the hill. Now a turret like building was built and used for local museum, and castle hill is covered by cherry trees. A large and secure castle compared with small quiet valley town well shows prosperity of Nanbu clan and also severe tension in internal conflict. Being used for only 52 years, Sannohe castle was an important ship for Nanbu clan which survived turbulent storm and handed down its history to posterity.


30 minutes walk from Aoimori-Tetsudo line Sannohe station. 20 minutes drive from Hachinohe-Jidoshado Expressway Ichinohe interchange.

Pictures (click to enlarge)

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