In the leadup to Expo ‘70, Kobayashi worked with Goji Hamada, Kazuo Kawasumi, Masanobu Yoshimura, Yasuharu Yukino, and Tanaka Norio as the design firm Kantsū (Penetration), which produced the ABAB Akafudado store in Ueno, and a collaborative project at Expo ’70, among other projects. Kobayashi and Kantsū also worked as part of Masanobu Yoshimura’s team producing ravens and other objects for the Textiles Pavilion at Expo ’70.