These stone daggers were used from the end until the last Jōmon Period (approximately 3,000-3,500 years ago). Japanese archaeolosists believe that these daggers were used for witchcraft. The bump on the dagger pictured to the left appears to be the end of the dagger, and the cylinder-shaped portion of this dagger becomes thinner towards this end. The middle of this dagger is thinned out on both sides, appearing to be the dagger's edges. Also, there are various patterns carved into the bottom end of this dagger.