Fourteen "Dotaku" bronze bells and seven halberds were excavated by coincidence at "Sakuragaoka", a hillside of Mt. Rokko in Nada ward, Kobe in 1964. They are supposed to be cast in the middle Yayoi period (from the BC 2nd to the AD 1st century). Among these dotakus, No. 4 and 5, on which figures of humans and animals were cast, are especially valuable. They are considered as the oldest drawings in a certain manner in the Japanese art history.