, also known as a BKF chair, is a style of chair featuring a folding frame and a large cloth sling hung from the frames highest points. This design is popular for portable recreational seating.
The BKF chair is a modern update to a design known as the Tripolina chair, a portable chair introduced in the early 20th century. Jorge Ferrari Hardoy along with Antonio Bonet and Juan Kurchan developed the BKF in 1938 for an apartment building they designed in Buenos Aires. On July 24, 1940, the chair was shown at the 3rd Salon de Artistas Decoradores exhibition where it was discovered by the Museum of Modern Art. At the request of MoMA design director Edgar Kaufmann Jr., Hardoy sent 3 pre-production chairs to New York. One is in the MoMA collection and one is at the Frank Lloyd Wright house Fallingwater, but no one knows where the third chair went. Naming the BKF as one of the "best efforts of modern chair design," Kaufmann accurately predicted that it would become extremely popular here. Likewise, Hans Knoll recognized its commercial potential and added it to the Knoll line in 1947.