Wednesday, July 29, 2020

Usui Castle -History of peninsular brave (8) Joint struggle with god of war-

Usui Castle

-History of peninsular brave (8) Joint struggle with god of war-



Name: Usui castle (Usui-jo)
Place: Jonouchi Sakura city, Chiba
Type: Hill Castle
Built: 12th century?
Remaining remnants: Clay walls and dry moats 

Brief History

Continued from Part 7

Usui castle (臼井城) is located at the edge of plateau which is about 20 meter height from hillside, 1.6 kilometer long and 0.8 kilometer wide at the north of Keisei Sakura station. 

Currently this plateau is surrounded by rice field, but formerly north, west and east side of the plateau is encircled by Lake Inba-numa and muddy field before land reclamation, and only south edge is connected to the main boy of Shimousa Daichi plateau.

Castle site faces Narita-Kaido road, one of major road connected Tokyo Bay coast area and Kashima or Choshi area, the mouth of Tone-gawa river. Furthermore, by river transportation from Lake Inba-numa it was connected to upstream of Tone-gawa river or coast area of Lake Kasumigaura. It not seems so now but it was formerly a center of wide range of local transportation.

Origin of Usui castle

Precise year is not clear but Usui castle is said to be built in 1114 by local lord Usui clan. Usui clan was a branch family of Chiba clan, which stem from Taira family. Chiba clan supported Yoritomo Minamoto (1147-1199), the founder of Kamakura Shogunate who was defeated at the battle of Ishibashiyama and ran to Boso peninsula, and contributed to the establishment of Shogunate.

Soon Chiba clan declined due to internal conflict in the Shogunate, but continued as the governor of Shimousa province (north part of Chiba prefecture) and resided Chiba castle (Chiba prefecture) at the east of current Chiba city central. Usui clan also continued as a major branch family of Chiba clan, instead of continuous troubles and internal conflicts.

In the middle of 15th century, amid the battle of Kyotoku between Kamakura Kubo Highness and Kanto Kanrei, Chiba clan divided into both side then main family of Chiba clan was replaced by its branch family Makuwari clan. But remaining main family of Chiba clan ran to Dokan Ota (1432-1486), an excellent general under Ogigayatsu Uesugi clan and who built Edo castle (Tokyo metropolis).

Attack by Dokan Ota

In 1478, Dokan Ota broke the army of Makuwari clan at the battle of Sakainehara, then chased the enemy to Usui castle. Dokan once captured Usui castle, but facing counter attack of Makuwari army Dokan at last retreated from the castle, losing his younger brother Suketada Ota (?-1479). Later Dokan himself was assassinated by his master, then Makuwari clan kept the leader of Chiba clan then changed surname so.

In 1517, Yoshiaki Ashikaga (?-1538), the younger brother of Koga Kubo Highness Takamoto Ashikaga (1485-1535), suddenly captured Oyumi castle (Chiba prefecture) from Hara clan and named as Oyumi Kubo Highness under the support from Mariyatsu Takeda clan. Chiba clan belonged to Koga Kubo Highness, but Usui clan supported Oyumi Kubo Highness this time.

Oyumi Kubo Highness once increased their power, but soon declined after the death of Takamoto Ashikaga on the first battle of Konodai in 1538. Usui clan had to return to Chiba clan, and was monitored by Tanesada Hara (1507-1569), the leader of Hara clan who recovered Oyumi castle. 

Fierce battle of Satake army in Shimousa province

In 1561, Nobushige Masaki (1540-1564), a brave general of Satomi clan which was the warlord of Awa province (south edge of Boso peninsula) and captured former territory of Mariyatsu Takeda clan at Kazusa province, tried to proceed into Shimousa province and attacked Oyumi castle and Usui castle managed by Hara clan. 

For Satomi clan which fiercely competed with Hojo clan, the warlord of Sagami province (Kanagawa prefecture), Shimousa province was a critical area for its economic and agricultural resource, sea control of Tokyo bay, and connection to Koga Kubo Highness at Koga castle or other anti Hojo local lords such as Satake clan. Once Satomi clan would be pushed out from the province, it might be seriously difficult to compete with Hojo clan only from Kazusa province and Awa province. 

Oyumi castle and Usui castle were once captured by Satomi clan, but after the defeat of Satomi army at the second battle of Konodai before Hojo army in 1564, Hara clan recovered two castles and formally became the lord of both castles. As Oyumi castle was too close to Satomi clan, Hara clan used Usui castle as their main base and strengthened its facilities.

Structure of Usui castle

Core part of Usui castle is built utilizing small projection of the plateau which is about 100 meter long spreads east and westward. This projection is divided into central area at eastward and secondary area at westward by about 15 meter wide dry moat and clay bridge as a corridor. Secondary area is separated from the main body of plateau by 20 meter wide huge dry moat.

Third area is difficult to distinguish now but continues over 500 meter long at the east edge of plateau, encircling entrance into secondary area. At the south of third area next to the root of plateau where Kashima Kaido Road passes, there might be a ground of the residence of the road.

Usui castle is protected by six forefront forts built around the plateau. Most fort was lost by development but Shukuuchi Fort existed at southeast of central area still keeps original structure. Outside of plateau, opposite of Lake Inba-numa branch castles encircled Usui castle, and Moroto castle at north of Usui castle well keeps its structure such as clay wall and dry moat.

Joint struggle of Kenshin Uesugi and Satomi clan

In 1566, Kenshin Uesugi (1530-1578), the warlord of Echigo province (Niigata prefecture), marched to Kanto region across Mikuni-Toge pass then fell Oda castle (Ibaraki prefecture) of Oda clan and next attacked Usui castle. At this time Kenshin Uesugi fiercely conflicted with Hojo clan all around of Kanto region, since its first march to Odawara castle in 1561.

Satomi clan and Hojo clan conflicted over 30 years for Shimousa province, but the gap of both clan increased year by year then Satomi clan fell into severe situation. On the other hand, Kenshin Uesugi supported Norimasa Uesugi (1523-1579), who was Kanto Kanrei but was broken by Hojo army and ran to Echigo province. Satomi clan and Uesugi clan were both the enemy of Hojo clan then Satomi clan asked the assistance of Uesugi army.

Kenshin Uesugi was an excellent warlord praised as “god of war”, but it was 300 kilometer apart from his territory Echigo province. It was necessary to keep the supply line for expedition, and as Tokyo bay area is firmly held by Hojo army, Kenshin could not directly enter Shimousa province. Then Kenshin might plan to use Tone-gawa river and Lake Inba-numa as supply line and use Usui castle as forefront castle to contact with Satomi army.

Attack by Kenshin Uesugi

On March 1566, Uesugi army had 15,000 soldiers fiercely attacked Usui castle protected by 2,000 soldiers. Hara clan requested reinforcement army to Hojo clan, but Hojo clan could not send sufficient help thus Hara clan had to cope with Uesugi army only by themselves. Uesugi army fiercely attacked Usui castle and fell third area, then expected to seize the castle soon.

But according to military tale, just this time Taneharu Shirai (?-?, known for Buddhist name Josan) resided in the castle. Taneharu Shirai was a branch family of Shirai clan, and wondered various provinces to study tactics. Josan looked Hara army was gathered and had high morale, and Uesugi army was mixed up and had low morale.

Looking at final attack of Uesugi army to Usui castle, Josan ordered to open the gate and charge into enemies. Uesugi army was unexpected the counter attack from the castle and gathered at narrow third area, then confused and retreated with damage.

Failure of siege

Next day Kenshin expected same counter attack and prepared for intercept, but this time Hara army stayed at the castle. Irritated Kenshin attacked the castle, but this time the wall of the castle fell into Uesugi army, then confused Uesugi army again retreated with the charge of Hara army.

Considering limitation of supply and distance, but it was a total defeat of Kenshin unlike his reputation as the god of the war, and local lords once gathered to Kenshin left Uesugi army then Kenshin could not invade into east half of Kanto region again. Shirai castle was exactly was a tide mark and turning point of Kenshin.

The failure of the siege of Usui castle meant the failure to establish connection between Satomi army and Uesugi army. Satomi army once suffered severe defeat at the second battle of Konodai in 1564, and due to the failure of Kenshin local lords of Shimousa province altogether turned to Hojo clan. Satomi clan had to retreat from Shimousa province, and Hojo army reversely invaded into Kazusa province (middle part of Boso peninsula).

Afterward of castle

After the attack of Kenshin Uesugi, the situation of Usui castle and Hara clan was relatively stable belonging to Hojo clan. Hara clan was treated as an independent power of Chiba clan from Hojo clan, and was recorded to have 2,500 cavalries equivalent to Chiba clan of 3,000 cavalries.

In 1590, Hojo clan was ruined by central ruler Hideyoshi Toyotomi (1537-1598) in his Odawara campaign. Hara clan shared the fate with Hojo clan, and Usui castle was given to Ieyasu Tokugawa (1543-1616) who seized former territory of Hojo clan. Ieyasu placed his general Ietsugu Sakai (1564-1618) on Usui castle.

In 1604 Usui castle was abolished along with the movement of Ietsugu Sakai to Takasaki castle (Gunma prefecture). But considering the importance of the area, Ieyasu built Sakura castle only 3 kilometer east from Usui castle, at the middle of Usui castle and Motosakura castle (Chiba prefecture), the last main base of Chiba clan.

Now all building was lost but structure of central area and secondary area is mostly kept, along with Shukuuchi fort and Moroto castle. Not so technically advanced structure and lost outer areas give the impression of not so strong, but carefully looked this castle has sufficient defense facilities and size as a total. This gap might have trapped even Kenshin Uesugi praised as the god of the war.

Continue to Part 9


30 minutes walk from Keisei-Dentetsu Honsen line Keisei-Shirai station. 30 minutes drive from Higashi-Kanto Jidoshado Expressway Yotsukaido interchange to parking of castle park. Moroto castle exists at Inba-numa Koen park opposite of Funato Ohashi bridge from Usui castle.

Related Castles

Kururi Castle -History of peninsular brave (7) seesaw game-
Sanuki Castle -History of peninsular brave (9) revival victory extend history of Satomi clan-


Pictures (click to enlarge)

Usui Castle

Shukuuchi Fort

Moroto Castle

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