Folding armchairs Rex by Niko Kralj, Slovenia, 1960s.

Although now dubbed the King of Slovenian Design, Niko Kralj was for many years one of the great unsung heroes of industrial design.

The late architect and furniture designer Kralj was known for groundbreaking seating and tables that seamlessly blend functionality with an elegant economy of line. He received little recognition outside his own country, despite registering 120-plus patents and models, including those for the Mosquito bar stool — named for its winglike seat and first produced in 2012 — and a number of inventive “foldables,” like the Rex coffee table and Rex daybed for children.

Sleek and space-saving, Kralj's iconic foldable Rex rocking chair was created in 1956 — it epitomizes his sleek and laconic minimalism, conveying a sense of strength and fluidity, both in its pleasingly geometric open form and its gracefully arching folded silhouette. A contemporary version of Kralj’s mid-century masterwork is produced by the Ljubljana-based furniture company Rex Kralj.

Over the course of his career, Kralj also established close ties with such design giants as Charles and Ray Eames, Richard Buckminster Fuller, Olof Pira and Ilmari Tapiovaara, all proponents, like him, of an aesthetic that inhabits the sweet spot between elegant simplicity and pragmatism.

Today, Kralj’s timeless rocking chairs are in the collections of a number of international museums, including New York’s Museum of Modern Art, Copenhagen’s Designmuseum Denmark and the National Technical Museum Prague.

Find vintage Niko Kralj furniture on 1stDibs.