An ancient stone sluiceway which includes a turtle-shaped stone basin has been excavated from among the Sakafuneishi ruins in Asuka. The sluiceway was situated 2.5 meters to the south of the oval- and turtle-shaped basins.
Archaeologists believe that the ancient stone sluiceway channeled water from a spring (that still flows today) to the turtle-shaped basin.
Various sculpted stone relics believed to be evidence of the existence of a water source near the ruins of the seventh-century Asukakyo palace had also already been unearthed at the site. The opening of a square shaft in the direction of the spring measuring 1.8 meters x 2.4 meters was surrounded by stone blocks. At the center of the shaft was a tower 1.3 meters high. The discovery of the sluiceway is thought to support the view that the Sakafuneishi ruins were used by Empress Saimei (594-661) for religious services using water from these channels.
These findings were the first time archaeologists succeeded in tracking down a water source and the path that water would have taken.