Walter Knoll's Osuu bends wood to its limit: a 6 kg flowing chair — Red Dot BoB 2025

Walter Knoll's Osuu began as a challenge to Foster + Partners: design a lightweight wooden chair. Mike Holland, who led the project, said the design evolved gradually from the informal character of traditional wooden chairs, driven by material exploration and by lightweight-construction ideas from aircraft engineering.

The breakthrough was joining the two great techniques of wood furniture history. Steam bending, pioneered by Michael Thonet in the 19th century, shaped the solid roundwood; molded plywood, cultivated by Charles and Ray Eames, formed the seat. Earlier generations could not yet make a seat and backrest in one piece, so Osuu combined them: solid, steam-bent roundwood curves around the body, becomes the armrests and upper backrest, and flows directly into the front legs, while a molded 3D-veneer shell leans against the inner arch and sweeps forward over the frame.

Walter Knoll pushes the steam bending to its physical limit and bends walnut at narrow radii, a skill only a few manufacturers master. The result has no visible joints — parts are glued with formaldehyde-free adhesives — and no cross braces between legs, yet it weighs only 6 kg and holds a seated body in an ergonomically tested curve.

Woods are FSC-certified oak or walnut sourced from the Black Forest and finished with natural hard wax; optional felt or saddle-leather seat pads attach with clasps, tool-free. The chair launched around Milan Design Week 2024 and in 2025 took both the iF Design Award Gold (75 gold trophies from nearly 11,000 entries) and Red Dot: Best of the Best, where it earned 98 of 100 winner points under Red Dot's new judging method.