Traces of the Awa Satomi Clan ~ DEC, 2025 ~

The Satomi clan was famous as a Sengoku daimyo based in Awa, and after the Battle of Sekigahara, was incorporated into the Edo shogunate and feudal domain system as a daimyo with 122,000 koku of rice and its main castle in Tateyama. Just before the Winter Siege of Osaka, the Satomi clan was implicated in the removal of Okubo Tadachika's fief and was ordered to be transferred to Kurayoshi, Hoki, with 30,000 koku of rice, but the actual territory there was only 4,000 koku, so it was almost like a removal. The feudal lord, Satomi Tadayoshi, had married Okubo Tadachika's granddaughter three years earlier. The Awa Satomi clan was originally founded when Satomi Yoshizane, who was defeated in the Battle of Yuki (1441), established his base at Shirahama Castle and aimed to restore the Satomi clan.

At the foot of the Shirahama Castle ruins stands Jojuin Temple, founded by Yoshizane. It was founded in 1444, three years after the Battle of Yuki.

The Pacific Ocean can be seen from Yoshizane's grave. Wooden statues of the first lord Yoshizane, the second lord Shigeyoshi, the third lord Yoshimichi, and the fifth lord Yoshitoyo were made here in 1647. It is interesting to note that the fourth and sixth generations have been skipped, but this may be related to the succession dispute that occurred within the Satomi family in 1534.

The Satomi clan was originally a branch of the Nitta clan that branched off from Nitta Yoshishige, and in a broad sense is of the same clan as the Tokugawa clan, who called themselves the Nitta Genji. Yoshishige was the grandson of the famous Hachiman Taro Yoshiie, and inherited the official position of Yawata Manor in Usui County, Kozuke Province, which was the foothold that the Kawachi Genji (Minamoto no Yorinobu) used to advance into the Kanto region. The name still remains as the name of a town in Takasaki City. Seven generations after Yoshishige, Nitta Yoshisada appeared, who overthrew the Kamakura shogunate.

The above-mentioned internal conflict within the Satomi clan arose after the death of the third head of the family, Yoshimichi, between his son (Yoshitoyo) and nephew (Yoshitaka). This was during the time when Hojo Ujitsuna had pacified Sagami and was strengthening his involvement in Musashi and the Boso Peninsula. Ujitsuna approached Yoshimichi's younger brother, Sanetaka, but Yoshitoyo, who succeeded him as the fourth head of the family, assassinated Sanetaka, so Yoshitaka avenged his death (at the Battle of Inukake) and succeeded him as the fifth head of the family. The battlefield unfolded in the small mountains of Awa.

Along the road at the foot of the nearby Takita Castle ruins, there is a small memorial tower called Takita's Blue Tomb. It belonged to Okamoto Yorishige, who fought bravely to help Yoshitoyo escape after his defeat in the war, and his descendants still commemorate him today. Yoshitaka later expanded his influence throughout the Boso Peninsula, based in Awa.

Along with Sanetaka, Masaki Michitsuna, who was based in eastern Awa, was killed by Yoshitoyo. He was originally a member of the Miura clan, which had been annihilated by Hojo Soun, but had fled to this area and served the Satomi clan. Like Satomi Yoshitaka, Michitsuna's sons, Tokishige and Tokitada, fought alongside Yoshitaka at Inukake and were responsible for the prosperity of the Satomi clan, a feudal lord in the Sengoku period. Shobunji Temple houses the grave of Tokitada's son, Yoritada. Yoritada's daughter, Oman no Kata, was Ieyasu's concubine and gave birth to Yorinobu, the founder of the Kishu Wakayama domain, and Yorifusa, the founder of the Mito domain. His son, Tameharu, reverted to the Miura surname and his descendants inherited the position of chief retainer of the Kishu domain (20,000 koku).

Near Shobunji Temple is the ancient temple Ishido-ji, said to have been built by Gyoki during the Nara period. It was rebuilt by the Satomi clan after a fire in 1487, but many of the 15th century buildings remain, and the entire area has been designated an Important Cultural Property.

During the Sengoku period, the Hojo and Satomi clans were enemies, and the most symbolic battle of this was the First Battle of Konodai (present-day Matsudo City). At the time, Koyumi Kubo (Ashikaga Yoshiaki), a branch of the Koga Kubo based in Chiba, confronted Hojo Ujitsuna, who had seized Edo Castle, but the Satomi clan supported Koyumi Kubo and fought back. This took place after the time of Ota Dokan, whom I wrote about last week.

Satomi Yoshitaka took in Yoshiaki's son (Yorizumi) who was killed in battle and entrusted him to Ishido-ji Temple. The legitimacy of the Kanto Ashikaga clan continued to be an important trump card in the conflict with the Hojo clan, but Toyotomi Hideyoshi's Siege of Odawara brought an end to the Sengoku period in Kanto. Hideyoshi took Yorizumi's daughter as a concubine, married his son (Kunitomo) to a princess from the Koga kubo family, and gave him territory in Kiryugawa, Shimotsuke, and treated him as a daimyo (feudal lord) (1593, 2nd year of Bunroku). Tokugawa Ieyasu later continued this treatment, ushering in the Meiji Restoration.

Enmei-ji Temple is the family temple of Satomi Sanetaka, Yoshitaka, and Yoshihiro. Some people divide the Satomi clan into early and late periods based on the time before and after the Battle of Inukake, but this temple can be considered the family temple of the late Satomi clan. During the time of Yoshitaka and Yoshihiro, the Satomi clan's territory extended across the entire Boso Peninsula, but the family was plagued by many internal conflicts over inheritance, including between Yoshihiro's children (Yoshiyori and Yoshishige).

Yoshiyori handled his affairs well against Hideyoshi and was granted all of his territory (Awa, Kazusa, and part of Shimousa) at first, but Hideyoshi criticized his efforts to regain his former territory by using Ashikaga Yorizumi, and he was eventually confined to the Awa province. Jion-in Temple was founded by Yoshiyasu, who moved the Buddhist hall that was located in Tateyama Castle.

At the nearby Myoen-in Temple, there is a rare ginkgo tree called Ohatsukirappaicho. It is a ginkgo tree with trumpet-shaped leaves and fruit. There is also a charred bell tower on the temple grounds. The top of the building was apparently burned when a B29 dropped an incendiary bomb on its way back from an air raid on Tokyo in May 1945.

Tsuruya Hachimangu Shrine, which was built as the main shrine of Awa Province during the Heian period, was also protected by the Satomi clan. The area in question is said to be near the Awa provincial capital, and Awa Kokubunji Temple is also nearby. Since the small Awa Province was incorporated into Kazusa Province for a period during the Nara period, the construction of provincial temples seems to have been slower than in other provinces.

I've been wondering what the source of power was for the Satomi clan, who swept across the Boso Peninsula from a small piece of land at the end of the peninsula and competed with the Hojo clan, the Kanto region's hegemons, and it seems that the power of their navy was a major factor. For the Hojo clan, a land-based power, the Satomi clan were forced to wage guerrilla warfare in mountainous terrain where they could not expect much even if they conquered, and they were resisted by piracy from the sea, making them a nasty enemy with little cost-effectiveness. I went up to the observation deck at Uomizuka, where Minamoto no Yoritomo is said to have fled to the Boso Peninsula after being defeated in the Battle of Ishibashiyama and fought against local lords.

In 1556 (the second year of the Koji era), Satomi Yoshihiro crossed the sea and raided Kamakura, abducting Seigakuni (the daughter of Ashikaga Yoshiaki) who was at Taiheiji Temple, returning her to secular life, and making her his wife. Due to the relationship between the Satomi family and the Koyumi kubo, it is said that she was originally engaged to be his wife. This was a testament to the Satomi clan's reputation as a naval state. Hojo Ujiyasu was so upset that he abandoned Taiheiji Temple.

After driving out the Satomi clan, the Tokugawa shogunate never again placed a major feudal lord in this area. They must have understood well why the Hojo clan had such difficulty. Tateyama has an image of having lost time to develop as a castle town, but the climate is warm, the fish is delicious, and from the ruins of Tateyama Castle you can get a good view of Mt. Fuji across the Uraga Channel. I look forward to future revitalization efforts that utilize X JAPAN and the Satomi clan (11 years ago, I was able to see Mt. Fuji from Tateyama Castle during cherry blossom season).