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Hiraiwa Castle Ruins (Myodai-ji Mansion Site)

Relocation of urban Administration to Okazaki Castle

 Before Tokugawa Ieyasu’s ancestors, the Matsudaira clan, captured Okazaki, the Saigo clan ruled the area from Hiraiwa Castle around the current Myodai-ji Temple area. The warlord Saigo Yoritsugu is said to have built the first Okazaki Castle in the mid 15th century as a fort to counter the Matsudaira, while maintaining his residence at Hiraiwa Castle. In the early 16th century, Matsudaira Kiyoyasu overthrew the Saigo, and rebuilt Okazaki Castle, making it his base. The seat of administration was slowly transferred from the Myodai-ji area to around Okazaki Castle. When Tanaka Yoshimasa became Lord of Okazaki in 1590, he rebuilt the castle town and redirected the Tokaido highway through the castle grounds, effectively closing the many inns and post town functions of the Myodai-ji area.

Excavations of Hiraiwa Castle Ruins

 Archeological excavations were conducted between 2013 and 2016 as part of the Higashi Okazaki Station maintenance project.

The excavations revealed the ruins of many buildings, drainage trenches and wells, indicating this was a settlement from ancient times to the Middle Ages. It is presumed that this was the site of a mansion, due to the regular arrangement of large trenches and building remains. As there were few archeological traces from the early modern era, and so it is believed that the town had been in decline as urban administrative functions shifted to around Okazaki Castle.

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Hiraiwa Castle Ruins (Myodai-ji Mansion Site)

Relocation of urban Administration to Okazaki Castle

 Before Tokugawa Ieyasu’s ancestors, the Matsudaira clan, captured Okazaki, the Saigo clan ruled the area from Hiraiwa Castle around the current Myodai-ji Temple area. The warlord Saigo Yoritsugu is said to have built the first Okazaki Castle in the mid 15th century as a fort to counter the Matsudaira, while maintaining his residence at Hiraiwa Castle. In the early 16th century, Matsudaira Kiyoyasu overthrew the Saigo, and rebuilt Okazaki Castle, making it his base. The seat of administration was slowly transferred from the Myodai-ji area to around Okazaki Castle. When Tanaka Yoshimasa became Lord of Okazaki in 1590, he rebuilt the castle town and redirected the Tokaido highway through the castle grounds, effectively closing the many inns and post town functions of the Myodai-ji area.

Excavations of Hiraiwa Castle Ruins

 Archeological excavations were conducted between 2013 and 2016 as part of the Higashi Okazaki Station maintenance project.

The excavations revealed the ruins of many buildings, drainage trenches and wells, indicating this was a settlement from ancient times to the Middle Ages. It is presumed that this was the site of a mansion, due to the regular arrangement of large trenches and building remains. As there were few archeological traces from the early modern era, and so it is believed that the town had been in decline as urban administrative functions shifted to around Okazaki Castle.