Tourbillon B1.618 Openwork
Model History
Presented at the 2021 Geneva Watch Days, the Tourbillon B1.618 Openwork is the first model with which Bianchet made itself known to the public and trade press, following the presentation of a prototype at Baselworld in 2019. The collection's name, "B 1.618," explicitly recalls the golden number (phi, approximately 1.618), used by the brand as the guiding principle for the proportions of the movement's entire architecture — a design choice Bianchet claims as unprecedented in the independent watchmaking landscape.
The tonneau-shaped case, made in titanium or in a carbon-titanium composite, houses a manual-wind calibre developed in collaboration with technician Olivier Mory, with a one-minute tourbillon visible through an extensively skeletonized dial. Two suspended flanges, enhanced with Super-LumiNova inserts, allow hours and minutes to be read without obstructing the view of the movement, leaving the tourbillon as the dial's absolute focal point.
The model was offered in two limited editions of 21 pieces each — one in titanium with red rubber accents, the other in carbon composite with blue accents — reflecting a small-series production positioning typical of high-end independent watchmaking.
Technical Specifications
Main Executions
The number "1.618" in the collection's name is not a random reference: it is the approximate value of the golden ratio (phi), the mathematical relationship tied to the Fibonacci sequence that Bianchet states it used to set the proportions of the calibre's entire architecture, from the layout of the bridges to the tourbillon's position on the dial.