— In its high jewelry version the Golden Bridge appears dressed in blue sapphires and white diamonds.
Reinventing the art of invisible setting
The gemsetting on the Golden Bridge requires skilled fingers, considerable experience, infallible precision as well as a keen eye. The first challenge lies in selecting the stones that will not only need to be extremely pure, but also able to fit seamlessly together. Size, cut, shape and color: everything must contribute to perfect harmony, since even the slightest wrong note would be immediately noticeable. In performing this delicate task, the artisan must rely solely on his experience and his trained eye. Once the stones have been selected, the gold surfaces of the Golden Bridge are meticulously prepared for the gemsetting.
The case and bracelet are set according to the classic invisible setting technique. Yet Corum had to reinterpret this demanding art when it came time to pave the dial, in order to avoid the smallest gems getting broken. Thus, the dial was first mounted upside down on a transparent plate, before meticulously pouring a silver-based alloy over the structure. By seeping into the tiny gaps between the stones, the matter thereby solidly holds together the stones. The latter, having thus fused to become a plate, could then be removed from the transparent backing, before being fitted on the white gold dial. It is at this precise moment that the magic of the invisible setting exerts the full force of its fascination, since the underlying metal structure completely vanishes to unleash the spectacular radiance of the sapphires and diamonds.
Caliber CO 11
The Golden Bridge houses Caliber CO 113. This linear caliber is capable of fitting inside both the tonneau-shaped case of the Golden Bridge (35 x 51.2 mm) and the more diminutive frame of Miss Golden Bridge (23.3 x 44.26 mm). It is a descendant of the first baguette movement in history created by Corum in 1980. A caliber that has become icon thanks to its vertical construction along a vertical axis – a design that makes the transmission of energy a true challenge.
Caliber CO 113 is extended by the 6 o’clock crown aligned with its vertical axis. An ingenious slipping-spring winding system serves to prevent any risk of forcing the mechanism, while a coupling clutch has been specially developed to dissociate winding from time-setting by means of a construction featuring wheels and pinions mounted between the mainplate and bridge.
The ultra-precise Caliber CO 113 is equipped with a variable-inertia balance ensuring impressive long-term regularity, rather than a classic index system. Further strengthening its performance, it is fitted with two visible bridge pillars that enhance its resistance and rigidity. Though complex, Caliber CO 113 remains aesthetic. Its 18K gold upper bridge bears the hand-engraved Corum signature, along with slender undulating motifs representing the three types of fern growing in the forests around La Chaux-de-Fonds, where Corum was born. The four sapphire crystals forming the watch glass, back and middle provide 360° views of the mechanism beating at a frequency of 4 Hz (28,800 vibrations/hour) and endowed with a 40-hour power reserve.