Born in Tokyo, Koike won the prestigious Tezuka Award in 1976, when he was 16. His style, similar to Katsuhiro Otomo and Moebius, is marked by vivid representations of psychedelic experiences. Drugs are an important part of his inspiration: "Except peyotl, I have tried almost everything: hashish, heroin, cocain, acid, magic mushrooms. From a strictly graphical point of view, however, LSD is most important by far.".