In prewar times, a chasho (tea dealer), who found the scraps of mochi left after the kagamibiraki (the custom of cutting and eating a large, round rice cake, which has been offered to the gods at New Year, on January 11) wasteful, roasted and mixed them with tea leaves, and this was said to be the beginning of genmaicha.
戦前に、鏡開きのときにできる餅屑を勿体無いと考えた茶商が、これを炒って茶葉に混ぜたのが始まりとされている。