A to Z of Expo Architecture: Kenzō Tange

Kenzō Tange, one of Japan’s leading architects of the 20th century, occupies the T position in the A to Z of Expo Architects. Known for combining Japanese traditions and Western influences in his celebrated urban projects, the Pritzker laureate was the main planner for World Expo 1970 Osaka and designed the Expo’s mammoth Festival Plaza.

In creating the Expo 1970 master plan following Uzō Nishiyama’s original proposal, Tange sought inspiration from the Japanese Metabolism Group (which he had co-founded), which sought to respond to the challenge of urbanisation through technological development. The Festival Plaza – the central point of the Expo site connecting all its different zones – was thus created as a testbed of a future city, using bold and advanced space frame techniques.

Its scale was unheard of; the double-layer frame sat 30 metres above the ground, and was 108 metres across by 297 metres long – only interrupted in the middle by Tarō Okamoto’s striking Tower of the Sun. The frame was composed of different-sized steel tubes connected to each other and was supported by lattice columns. The deck – composed of square-plan transparent plastic pneumatic – was hoisted into the air by pneumatic jacks, a unique and novel technique at the time.

Known as ‘the big roof’ during the Expo, the Plaza hosted the Expo’s thematic exhibits, and had several experimental capsules attached to it, showcasing alternative visions of urban living.

Dismantled following the Expo when the site was transformed into a park, Tange’s creation had a significant impact on structural engineering of the era, and contributed to the global debate on urban planning challenges. It received the 1970 Artificial Intelligence Journal (AIJ) Award, and served to promote the use of the innovative hoisting system used in its construction.