Stone Object in the Shape of Chinese Broadsword "Seiryu-to"

This is a stone tool made during the Jōmon Period (16,500-3,000 BCE). The name of this is derived from its similar appearance to Chinese broadsword "Seiryu-to". The arc of this stone tool has the edge of a sword, whereas this stone tool has a distinctive thin and linear back opposite of the edge. This characteristic shows the stone tool's lack of connection with the blue dragon sword. How this tool was used is unknown.