Jacks played in a distinct musical style fused with ambient psychedelic, surf, folk and jazz.
The group had a dark, introspective sound with an exploratory, improvisational edge and sometimes headed into moody instrumental excursions.
The Jacks typically employed reverb, tremolo and subtle fuzz-guitar and also utilized the vibraphone, organ and wind instruments such as the flute.
Lead singer Yoshio Hayakawa sung in Japanese and typically ranged from a low, calm and tranquil voice to throaty, desperate sounding wails.
Similarly, drummer Takasuke Kida would follow suit, going from subtle jazzy sounding fills to complicated, offbeat rhythms and manic cymbal crashes.