01 / Seishiden Site (清祀殿跡)
The sacred mirror sent to Usa Shrineis thought to have been cast here.
A prefecturally designated Historic Site in Saidosho (採銅所). Its origin is debated, but a record survives that in 720 Komiya Hachimangu (古宮八幡宮) offered a sacred mirror to Usa Shrine, and this is thought to be where that mirror was actually cast. The nearby tunnel is called Kanmabu (神間歩), and the building's earthen floor had a smith's hearth at its center.
- Prefectural Historic Site (1956)
- Record of the offering: 720
- Nearby tunnel: Kanmabu
