Designed in the 1880s by **Michael Thonet** and later refined by his son, August Thonet. Building on the steam-bent solid wood technique developed by Thonet in the 1850s, beech wood is softened by high-temperature steam and then hand-bent into a flowing circular backrest and curved legs, representing a mature application of bentwood craftsmanship. Born during the “Belle Époque,” this design builds upon the Chairs No. 14 and No. 18. To meet demands for greater comfort, it incorporates a rattan-woven backrest and an independent circular backrest structure, becoming a classic choice for European cafés and home dining rooms. As a key derivative of the Sonnet bentwood chair family, it, along with Chairs No. 14 and No. 18, defined European furniture styles from the late 19th to the early 20th century. It is widely used in cafés, restaurants, and home settings.