There is a theory that the bronze spearhead civilization, which used the so-called Three Imperial Regalia in its rituals - a sword, a mirror and a curved jewel, described in 'Gishiwajinden' and also in "Chronicles of Japan"- destroyed the bronze bell civilization, whose solemn rituals used bronze bells and which had spread from Kinki region to Tokai region.
近畿地方から東海地方にかけて広まっていた、銅鐸による祭祀を行っていた銅鐸文明を、「魏志倭人伝」に記載された道具であり、『日本書紀』にも著される矛（剣）、鏡、勾玉の、いわゆる三種の神器を祭祀に用いる「銅矛文明」が滅ぼしたとされる説。