All the posts, including munamochi-bashira, are hottate-bashira, which are erected by excavating a posthole to insert and secure the post without using any foundation stones. (Note: Today's Izumo-taisha Shrine is built on a sill.)
そして棟持柱を含めて、全ての柱が礎石を使わず地面に穴を掘って建てる掘立柱である（現在の出雲大社は土台の上に建つ）。