With their chaotic live sets, eccentric sound and organic upward trajectory, Shinsei Kamattechan are the must-see Japanese act this year at the eastern leg of Summer Sonic — which takes place, after all, in their home prefecture of Chiba.

Alongside acts such as Ling Toshite Sigure, Electric Eel Shock and Soutaiseiriron, Kamattechan are part of a new generation of Japanese artists whose popularity has grown by word of mouth, relying on amazing live performances and online activity rather than media saturation and marketing yen.

"We were playing live shows like any other band, but the venues were empty," recalls keyboardist/guitarist Mono as we sit in a family restaurant in a far-flung corner of Tokyo's Shimokitazawa neighborhood. Also present is drummer Misako, who was the last to join the band (in 2007); bassist Chibagin is absent due to illness, while vocalist, guitarist and songwriter Noko avoids interviews altogether. The members each go by one name and they all turn 25 this year.