In 1954, through the efforts of Hans Kocher, their chief designer, Buren patented a micro-rotor winding system (they called it a "planetary rotor") that finally saw production in 1957. By 1962, the design had been refined into the Cal. 1280 "Intramatic" which won the Prix D'Honneur at the 1964 Swiss National Exposition in Lausanne. In 1965 it was further refined into the Cal. 1320 (1321 and 1322). Both designs (the 1280 and 1320) featured a slightly larger swinging mass than the earlier models, which now swung over the center of the movement, necessitating indirect seconds and minutes (I'll explain that later). Like the "Super Slender", the "Intramatic" wound in both directions and featured mutual decoupling of the automatic and manual winding systems in an attempt to capitalize on all the winding power that could be squeezed out of its tiny rotor.

It was the "Intramatic" movement that Buren modified in a joint venture with Breitling-Leonidas, Dubois-Depraz, Hamilton (who owned Buren at that time) and Heuer to create one of the world's first automatic chronographs in 1969, the "Chronomatic". The "Chronomatic" featured a Dubois-Depraz chronograph module (8510) attached to the backside of the movement, effectively hiding the micro-rotor entirely within the movement.