Sunday, August 24, 2014

Ichinomiya Castle -Place of decisive battle at Shikoku campaign-

Ichinomiya Castle

-Place of decisive battle at Shikoku campaign-



Name: Ichinomiya castle (Ichinomiya-jo)
Place: Ichinomiyacho Tokushima city, Tokushima
Type: Mountain Castle
Built: 14th century
Remaining remnants: Stone walls, clay walls and moats
Title: 100 more famous Japanese castles

Brief History

Ichinomiya castle (一宮城) is located at a ridge of Ryuouzan mountain, a place of 150 meter height in Ichinomiya town. Ichinomiya town is located at the southwest edge of Tokushima plain, and historically this area has been the center of Awa country (Tokushima prefecture) before Edo era. Ichinomiya area is a small valley of Akuigawa river, and convenient for both communication and defense. Ichinomiya castle is one of the largest castle of Tokushima prefecture, and the castle of transition period from medieval castle to modern castle.

Build and expansion of Ichinomiya castle

Ichinomiya castle was originally built by Ogasawara clan in 14th century. Ogasawara clan was appointed as a governor of Awa country by Kamakura Shogunage in 13th century, and the branch house of Ogasawara clan lived at Ichinomiya castle and named as Ichinomiya clan. 

Later among the conflict between Emperor Godaigo (1288-1339), and Takauji Ashikaga (1305-1358), the founder of Muromachi shoghnate, Ogasawara clan supported Emperor side thus was replaced to Hosokawa clan by Muromachi Shogunate. After the several battles, Ichinomiya clan and Ichinomiya castle belonged to Hosokawa clan.

In the former half of 16th century, Hosokawa clan lost their power and Miyoshi clan, a chief vassal of Hosokawa clan seized Kinki region and east Shikoku island. Ichinomiya clan also belonged to Miyoshi clan, but when Motochika Chosokabe (1539-1599) expanded their power after 1570’s, Ichinomiya clan turned to Chosokabe clan. 

However, among the conflict between Chosokabe clan and Miyoshi clan, Motochika who was suspicious about loyalty of Ichinomiya clan extinguished Ichinomiya clan and managed Ichinomiya castle directly. Under Chosokabe clan, Ichinomiya castle was expanded into the most important base of Awa clan.

Structure of Ichinomiya castle

Ichinomiya castle consist several areas spread along the ridges of Ryuouzan mountain. There are two peak at the top of the mountain, and older areas and newer areas locate north peak and south peak respectively. The central area at south peak is a flat square space of 30 meter length, and covered with stone walls probably built at next Hachisuka period. 

The stone wall at central area is a genuine one of xx meter tall, and at xx side there is a large steps into the central area, might be guarded by turret gate, The central area is flat and has no basement of main tower, and a small tower might be built directly at the area. Behind the central area there still exist a ruin of cooking stone made by stones.

Along the surrounding ridges terraces separated by clay walls and dry moats spread. At the lower area surrounded by ridges there is a pond used as a water source, and this pond is securely guarded by clay walls. Along with the main route from hillside to hilltop old style stone walls are seen, and this also might be built under Hachisuka clan.

Ichinomiya castle at Shikoku campaign

In 1585, the conflict between central ruler Hideyoshi Toyotomi (1537-1598) and Motochika Chosokabe became severe, and Hideyoshi finally started Shikoku campaign against Chosokabe clan in May. Hideyoshi mobilized 100,000 soldeirs and marched to Shikoku island from three directions, and Motochika only had 40,000 soldiers and had to locate them to many castles at the border. 

Motochika himself stayed at Shiraji caslte (Tokushima prefecture) at the upstream of Yoshino-gawa river, and to protect Shiraji castle from attack through Awa country, he placed his important general Tadasumi Tani (1534-1600) and Chikatoshi Emura (?-?) with 9,000 solders at Ichinomiya castle.

In July, Toyotomi army of 40,000 soldiers lead by Hidenaga Toyotomi (1540-1591), the younger brother of Hideyoshi, sieged Ichinomiya castle. Ichinomiya stood over half month against five times enemy soldiers, and Hideyoshi proposed to Hidenaga that Hideyoshi ordered the siege by himself. But Hidenaga declined it and attacked the water source by mine workers and shut the water supply of the castle. 

Finally Tadasumi opened the castle to Hidenaga, and reported to Motochika that it was impossible to resist to Toyotomi army considering the difference of number of soldiers and equipments. Based on this opinion, Motochika surrendered to Hideyoshi and kept his house. In that mean, the battle at Ichinomiya castle was the largest and decisive battle of the campaign.

Afterward of the castle

After the battle, Iemasa Hachisuka (1558-1639), son of Masakatsu Hachisuka (1526-1586) who was one of the oldest general of Hideyoshi from start up period, was appointed as the governor of Awa province. Hachisuka clan used Ichinomiya castle as their base, and might build stone walls surround central area. 

But as Ichinomiya castle has only limited space and was distant from plain area, Hachisuka clan newly built Tokushima castle and moved there in 16xx. Ichinomiya castle was kept as one of nine branch castles, but finally was abolished under Ikkoku Ichijyo Rei (one domain one castle rule) published in 1615.

Now powerful stone walls remain at central area and it shows this castle once was the center of Awa country. Beside this, long continuous areas guarded by steep cliffs reminds us the fierce battle occurred between Hidenaga and Chosokabe army.


20 minutes drive from Tokushima Jidoshado Expressway Aizumi interchange. In front of Danichiji temple, the 13th of 88 temples pilgrim road of Shikoku island.

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Pictures (click to enlarge)

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