Atsumi Peninsula: From Tahara to Toyohashi ~ JAN, 2026 ~

I usually plan my winter history tours to avoid snow as much as possible, and even when driving along the Pacific coast, I always check the weather forecast of Tokai area, where snow flows in from Mt. Ibuki, and Hakone tend to freeze easily. This year, I'm thinking of embarking on the pilgrimage to the 33 temples of the Saigoku Kannon Pilgrimage and the 88 temples of Shikoku, and I'm planning to start by heading to Seiganto-ji Temple in Nachikatsuura next month. I've driven the Isewan Coastal Road quite a bit, so I thought I'd take the ferry from the Atsumi Peninsula to Toba, and headed to Cape Irago to check it out.

Beyond the lighthouse, you can see Kamishima Island, where former army facilities were located, and beyond that, Toshima Island and other islands off the coast of Toba City, appear in the distance. A ferry ride between Irago Port and Toba Port takes 55 minutes, with 8-9 trips per day, making it easy to use. Near the lighthouse, there is a monument bearing a Man'yoshu poem commemorating Prince Omino, son of Emperor Tenmu, who was exiled to a nearby island. While the Nihon Shoki records that the prince was exiled to Inaba Province, the Man'yoshu states that he was exiled here. The circumstances are unclear, but one theory is that he sided with Prince Otomo during the Jinshin War. While it may be inappropriate, this is a beautiful and scenic exile site. This time, we head to Tahara and Toyohashi.

After Todaiji Temple was burned down by Taira no Shigehira, Shunjobo Chogen worked hard to rebuild it, and the Imperial Court decided to use tax revenues from Suo and Bizen provinces as the source of funds. There was also a need to produce a large amount of tiles, so a tile kiln was built in Irago, and the similarly built Mantomi tile kiln is located in eastern Okayama Prefecture. It may be that this land, where the pottery industry flourished, has had an unbroken connection to the pottery culture that followed.

I knew Tahara as the town of Watanabe Kazan, but I had always wondered how such a small domain (Tahara Domain, 12,000 koku) was able to maintain a castle (Tahara Castle). The Toyokawa Irrigation Canal was built after the war, and before that, agricultural production was hindered by a lack of irrigation water and poor soil. It was a major project to bring water from the Toyokawa River, which flows through Toyohashi, to the Atsumi Peninsula and Gamagori area, and I saw Hattachiike (an irrigation dam) located at the very tip of the peninsula.

The Toda clan ruled this area from the Middle Ages through the Sengoku period, and during the Kamakura period It was appointed as a local lord and laid down deep roots. Toda Munemitsu, who played an active role in the Onin War and is known as the founder of the Toda clan's revival, restored Choko-ji Temple, which was founded during the Kamakura period, and made it his family temple. The Toda clan became vassals of Ieyasu, and members of the family were promoted to multiple feudal lords, but the graves of successive generations of the Toda family, connected to the family that inherited Tahara, are lined up here.

After the Toda clan submitted to Ieyasu, six fudai daimyo (hereditary lords) emerged (Matsumoto Domain, Ogaki Domain, Utsunomiya Domain, etc.), none of which were stripped of their titles and remained in power until the Meiji Restoration. Among them, the Tahara Domain, which started with 10,000 koku, became a senior councilor (during the reign of Shogun Tsunayoshi) during the reign of Tadamasa and received successive increases in its stipend. His son, Tadazane (during the reign of Shogun Yoshimune), also became a senior councilor and rose to become a mid-ranking daimyo with 78,000 koku in the Utsunomiya Domain, surpassing the head family (Matsumoto Domain). Three years after becoming a senior councilor, Tadamasa was one of the people who executed Inaba Masayasu when Masayasu killed the chief councilor Hotta Masatoshi in the castle. Kira Kozukenosuke and Tanuma Okitomo were not the only victims of sword fighting in Edo Castle.

Throughout the Sengoku period, the Toda clan was caught between the Imagawa and Matsudaira clans and found themselves in a difficult environment, but they became hereditary retainers for their contributions to the suppression of the Ikko Ikki uprising, which Ieyasu had suffered through. After the Battle of Okehazama, Ieyasu aimed to unify Mikawa, and in 1565 (Eiroku 8), he besieged Yoshida Castle (Toyohashi City), which was defended by the Imagawa castle commander, and at the same time captured Tahara Castle. Ieyasu's headquarters was located at Chosenji Temple.

To the north of Tahara town is Mount Zao (250m above sea level), which has an observation deck with a panoramic view of Mikawa Bay, Toyohashi City, Tahara City, and the Pacific Ocean. Ieyasu conquered this mountain, unified Mikawa, and invaded Totomi to confront the Takeda clan.

Only a small part of the main keep and moat remain of Tahara Castle, and Tomoe Shrine is enshrined on the site of the main keep. In 1664 (the fourth year of the Kanbun era), Toda Tadamasa was transferred to the Tahara domain, and the Miyake clan became the lord of the domain, and the lord remained unchanged until the Meiji Restoration. The deities enshrined at Tomoe Shrine are Kojima Takanori, a loyal retainer of the Southern Court of Bizen and ancestor of the Miyake clan, and Miyake Yasusada, the founder of the domain who served Ieyasu and achieved military success.

Speaking of Miyake, the area where the Edo clan residence was located is called Miyakezaka, and the current Supreme Court is located nearby, as well as the former headquarters of the Socialist Party.

Watanabe Kazan was born into a family of upper-class samurai in the Tahara domain. In short, he was a man of great learning, and not only did he study a wide range of academic subjects, he was also an excellent painter. He became a chief retainer of the Tahara domain, and not only did he contribute to domain politics, but he also argued for coastal defense and opening up the country in response to approaches from foreign powers, which were becoming problematic at the time.

When I visited Koga some time ago, I visited the Takami Senseki Memorial Museum. Takami Senseki, a chief retainer of the Koga domain, seems to have had connections with Kazan, and his statue has been designated a national treasure and is housed in the National Museum. It is the newest national treasure painting.

Unfortunately, Kazan was confined to his hometown of Tahara and forced to commit suicide during the "Bansha no Goku" (Bansha no Goku) attack. Perhaps he was born 20 to 30 years too early. I stopped by the residence where Kazan was confined, visited Kazan Shrine, and then headed to his family temple, Johoji Temple.

There are the graves of Kazan and his son, Shoka. The shogunate sent officials to inspect Kazan's remains 24 days after his death, but refused to allow the construction of a grave. It would be until 1867, the final year of the Edo shogunate, that Kazan's honor would be restored.

Toyohashi was the previous post of Ikeda Terumasa, who built the famous Himeji Castle. After the Siege of Odawara, when Tokugawa Ieyasu was transferred to Kanto, Hideyoshi gave Terumasa a strategic location on the Tokaido and ordered him to renovate Yoshida Castle. This castle, which was fought over by many great warlords of Japan, including Imagawa Yoshimoto, Takeda Shingen, and Tokugawa Ieyasu, was transformed into a modern castle by Terumasa. After the Battle of Sekigahara, Terumasa moved to Himeji, and although Yoshida Castle's strategic value declined as Japan entered a period of peace, the castle town flourished as a post station on the Tokaido, and this legacy continues today as Toyohashi.

The castle ruins are being developed into Toyohashi Park, but even though it has been designated as one of the another 100 most famous castles in Japan, the only landmark building is a small museum (the remains of an iron tower), and local residents are apparently requesting and exploring the possibility of building a castle tower.

The Toyohashi Museum of Art, located within the park, was holding a special exhibition of its collection related to the Ashikaga clan and Tokugawa Ieyasu, which was well worth seeing. There was a wealth of correspondence related to Ieyasu, and I was particularly impressed by a valuable letter written in his younger days when he was still known as Motonobu. Those in the know know that Mikawa is also the place where many Ashikaga clan members descended from after the Kamakura shogunate appointed them as guardians. There are many clans, including the Hosokawa, Isshiki, and Kira clans, but Mikawa is also full of things to see in the Middle Ages.

Near Toyohashi, there is a rugged chert mountain, where the Iwaya Kannon Hall, said to have been founded by Gyoki, is located. Many stone Buddha statues are placed on the mountainside, and at the top there is a Kannon statue that can be climbed by climbing an iron chain.

I climbed the cliff-like stairs in the strong wind and poor footing, and at times like this I really felt my legs and hips weakening. I wonder how long I will be able to climb medieval mountain castles and shrines with many stairs on my own, so I would like to continue training.

The lord of Bizen, Ikeda Tsunamasa, was particularly devout and never neglected to make donations to the temple. He must have also had a strong connection to the temple as the birthplace of his great-grandfather, Terumasa.

This area was originally called Akumi, and was designated as the sacred territory of Ise Grand Shrine in the mid-Heian period. Akumikanbe Shinmeisha was originally located within Yoshida Castle, but in the Meiji period it became military land (18th Infantry Regiment) and was moved to its current location (south of Toyohashi Park). There is an annual festival called Oni Matsuri, in which red demons and tengu dance, which is said to have originated from the dengaku music of the Heian and Kamakura periods.

"Eejanaika" was an incident that occurred at the end of the Edo period, when people from Edo to Kamigata (Kansai) would dance wildly while wrapping talismans around their necks, and it is said to have originated at Muro Hachiman Shrine. Rumors of talismans falling from the sky caused a huge uproar, which was seen as divine will, and although the Yoshida clan tried to stop it, it continued unabated and spread from east to west. It is said to have continued for four months around the time of the Meiji Restoration in October, and it gives a sense of a great sense of liberation among the people who had been oppressed at the end of feudal society.

Two years ago, during the scorching summer heat of Hamamatsu, I traveled around and visited Honkoji Temple in Kosai City. The elder statesman Kuze Hiroyuki relocated the main gate and inner library from Yoshida Castle and donated them to the public, and Hiroyuki's son Shigeyuki later became elder statesman and lord of the Yoshida domain. The Yoshida domain's territory extended to the western part of Lake Hamana, and under Shigeyuki, it also took charge of managing the Arai Barrier, which may explain the sense of unity that runs from Toyohashi to Lake Hamana.

The best time to walk around the Atsumi Peninsula and Lake Hamana is around May, when the sun is gentle, rather than in the middle of winter or during the heatwaves. Mikawa is the land of the rulers mentioned above (Ashikaga and Tokugawa), and there are many sights to see, especially from the Middle Ages and early modern period, so I'm sure I'll have another opportunity to visit from Toyohashi in the future. I found a high-quality small restaurant in front of Toyohashi Station, so I could plan to become a regular customer.