Expo 70, held in Osaka, was a pivotal event for the Japanese people and their relationship with the rest of the world, demonstrating both the nation’s ongoing economic recovery from World War Two and the creative spirit of Japanese society and its artists. The event gained international acclaim for its adventurous architectural design, visual art and electronic music. Some of Japan’s most renowned composers were involved, but also present were the now-legendary rockers, the Flower Travellin' Band. A series of performances, billed as “Night Events” were held at the Expo; the most radical of these was "Beam Penetration and Mad Computer, plus the Minimal Sound of Motorcycles”, but its anti-establishment feel and general madness took the Expo organizers by surprise and it was cancelled after only one night, despite being scheduled for a longer run.

An air of myth developed around the event, but a recording of the event has been discovered and this release is the result. And what an event it was: a night-time sound-bomb with a fabled band, electronic sound and 50 motorcycles with horns blaring, spotlights, electronic billboards and a robot ― all flashing, roaring and howling at the night sky. This release comprises a CD, a 10-inch record with fold-out sleeve and large obi, plus fascinating notes in Japanese and English by Kenichi Yasuda, an expert on Japanese rock music, and Koji Kawasaki, a renowned researcher of Japanese electronic music, as well as rare photos.