This is the ceremony for cutting the materials for the Mifunashiro (which is shaped like a ship), the wooden box to hold the Mihishiro of both the Shogu and Betsugu shrines in the Jingu.
両正宮および別宮の御樋代を納める御船代（船の形をしている）の用材を切り出すにあたり行われる儀式。