Local people are maintaining the ruins for visitors.
Later History
The ruins of Ichinomiya Castle were designated as a Prefectural Historic Site of Tokushima Prefecture in 1954. Since then, the local Society for the Preservation of the ruins has been developing them such as maintaining the trail and cutting the grass regularly. That’s why we can always visit the ruins in a comfortable environment. Tokushima City has also been researching the ruins since 2017. The foundations of the castle buildings were found and how the castle was developed is being revealed.
My Impression
After visiting the three most popular castle ruins in Tokushima Prefecture, I noticed that they all once became the capital of Awa Province – Shozui Castle (up to1582), Ichinomiya Castle (from 1585 to 1586) and Tokushima Castle (from 1586). However, they also all have quite different features from each other. This is because the situation of Awa Province changed greatly in a very short time. The needs for castles also changed rapidly at that time. I recommend visiting the three castle ruins and comparing them.
How to get There
If you want to visit there by car: It is about 20 minutes away from Aizumi IC on Tokushima Expressway. You can park at the Ichinomiya Shrine or the Dainichi-ji Temple. By public transportation, take the Tokushima Bus on the Kamiyama Line bound for Yoriinaka from JR Tokushima Station and get off at the Ichinomiya-fudasho-mae bus stop. If you go there from Tokyo or Osaka, I recommend traveling by plane or using an express bus.
If you drive to the ruins of Ichinomiya Castle, you will go through the route on the narrow area sandwiched by Akui-gawa River and mountains. You can see that it is a good location for defending the castle. The entrance of the trail to the ruins is opposite of the Ichinomiya Shrine. You will need to climb to the top of the 144m high mountain, but the trail is well developed with stone steps.
The map around the castle
After climbing for a while, you will see a Vertical Moat or Tate-bori on the slope along the trail to prevent enemies from attacking. If you go to the branch nearby, you can see the ruins of the Warehouses.
Defense System using Natural Terrain
Going back to the main trail, you will reach an artificial steep cliff called Kiri-gishi under several enclosures. You can also see a fountain at the foot of the cliff. You will need to climb a zigzagged trail on the cliff to go further.
Even after climbing, you will still be under the bottom of an artificial valley called Hori-kiri. Enemies could have been counterattacked from the enclosures above. The valley divides the main portion of the castle and the Saizo-maru Enclosure. If you turn left at the valley, you will reach the Saizo-maru Enclosure. This enclosure is also called the Third Enclosure. “Saizo” originates from the name of the retainer who was responsible for the enclosure.
Going to Center of Castle
If you turn right at the valley, you will reach the ruins of the gate for the main portion which have two main enclosures – the Myojin-maru Enclosure and the Main Enclosure. These enclosures are connected by a long and narrow enclosure called the Belt Enclosure or Koshi-guruwa
If you turn right again at the gate ruins, you will be in the Myojin-maru Enclosure. This enclosure is also called the Second Enclosure and the spot where the ruins of the building with veranda, maybe for sightseeing, was found. You can even now see a good view of the center of Tokushima Prefecture to the east.
Great Stone Walls of Main Enclosure
If you go back to the gate ruins and go left from the front of it, you will finally reach the Main Enclosure on the top of the mountain. You may be surprised to suddenly see the great stone walls which were built by the Hachisuka Clan. The stone walls of this castle are very rare and beautiful because they were piled up using stones with a dark-green striped pattern called chlorite-schist. These stones are also known as Green Stones of Awa. The same pattern of stone walls can also be seen at Tokushima Castle that the Hachisuka Clan built after they used Ichinomiya Castle.
There is only the small building of Wakamiya Shrine. The stone foundations of the Main Hall for the lord were found recently, which were also built by the Hachisuka Clan. You can also see a good view of the area around, including Akui-gawa River.
Ichinomiya Clan built it in Period of Northern and Southern Courts
Ichinomiya Caste was the largest mountain castle in Awa Province (what is now Tokushima Prefecture) on Shikoku Island. It is said that The Ichinomiya Clan first built the castle in the 14th Century during the Period of the Northern and Southern Courts. Many battles happened across the county, so warriors started to build mountain castles to protect themselves. After the governance of Awa Province got stable, The Ichinomiya Clan seemed to live in a hall at the foot of the mountain and used the castle in an emergency like other clans used to do.
The location of the castle
Motochika Chosogabe captured it in Sengoku Period
In the late 16th Century during the Sengoku Period, many battles happened again in Awa Province. Narisuke Ichinomiya, the lord of the Ichinomiya Clan, managed to survive under the Miyoshi Clan, the governor of the province, and partly thanks to Ichinomiya Castle. After that, he changed his mind to support Motochuka Chosogabe. Motochuka who was from Tosa Province in the south, invaded Awa Province in 1582. However, Narisuke was killed by Motochika probably because Motochika doubted Narisuke’s change of mind. Ichhoinomiya Castle was captured by Motochika.
Ichinomiya Castle was not only a large mountain castle but also Akui-gawa River flowed in front of the gate as a natural hazard. It also had a fountain and warehouses inside, so it could be besieged for a long time. It was also near the center of the province. For a warlord who aimed to govern Awa Province by power, it was necessary to get such a strong and good-located castle as soon as possible. Motochika sent one of his senior vassals, Tadazumi Tani, to Ichinomiya Castle to maintain it.
Castle once became Capital of Awa Province
In 1585, the ruler, Hideyoshi Toyotomi sent over 100,000 soldiers to Shikoku Island to capture it. Ichinomiya Castle with about 10,000 defenders was besieged by about 40,000 attackers. The siege lasted for nearly one month and the castle was open as Motochika surrendered to Hideyoshi. Hideyoshi also sent one of his retainers, Iemasa Hachisuka as the lord of Awa Province. Iemasa chose Ichinomiya Castle as his home base, that meant the castle finally became the capital of the province. He built stone walls in the Main Enclosure on the top of the mountain though the castle had been all made of soil. He also built his Main Hall in the Main Enclosure and a building with a veranda in another enclosure, which might have been used for sightseeing.
However, Iemasa moved his home base from Ichinomiya Castle to new Tokushima Castle facing the sea the next year in 1586. It is said this was due to Hideyoshi’s instruction to build the network of sea transportation. The situation rapidly changed after Hideyoshi’s unification of Japan. The peak of Ichinomiya Castle lasted for just one year. After that, the castle was considered one of the branch castles called the Awa Nine Castles while the governance of Awa Province was not stable. The castle was finally abandoned soon after the Law of One Castle per Province by the Tokugawa Shogunate in 1615.