Jōmon Period is a prehistoric period that lasted from approximately 16500 to 3000 years ago. In world history, this is equivalent to the time of the Middle Stone Age (Mesolithic Era) or the New Stone Age (Neolithic Era). During Jōmon Period, people used tools including pottery, lived in pit dwelling houses and threw trash away in a shell mound called Kaizuka. A clay figure called ‘Jōmon Venus’ was discovered in Nagano and is now a national treasure. It was considered as an object of worship in Jōmon Period. After this period, Yayoi Period began. In Yayoi Period, people practiced making bronze and iron casting. They also employed a method of wet rice cultivation as well as building ancient mounded tombs called kofun.