Kengo Kuma brings together several pavilions under one roof. To create the intended elongated, open building, more than sixty identical porticos, spaced 3.8 meters apart, are placed one after another. The porticos are made from a custom-designed composite material combining wood with perforated steel plates glued to both sides. Each portico spans the full width of the building, which varies between 23 meters at its widest point and 10 meters at its narrowest. Within a constant thickness, the ratio between the steel and the wood in each portico is optimized depending on the span, offering clear advantages in terms of detailing and finishing. The steel plates are strong and stiff on their own, but too thin for large spans. Conversely, the spans are too great to control deflection using only wood. The portico system also requires rigid corner connections, which the steel plates provide elegantly. The composite material has been extensively tested to ensure that it will continue to meet structural performance requirements after years of temperature and humidity fluctuations. The structure was designed in Japan by ejiri structural engineers, led by Pieter Ochelen, who is now a member of UTIL’s core team. The execution was carried out by the Swiss engineering firm ingphi.