A rare set of complications, an openworked movement, and a spherical hairspring.

Following its headline April launch, Vacheron Constantin has nothing left to prove. To celebrate its 270th anniversary, the manufacture presented collectors of refined mechanics with the most complicated wristwatch in the world: the Soleria Ultra Grand Complication, featuring no fewer than 41 complications.
 

Against that backdrop, the June debut of the Les Cabinotiers Temporis Duo Grand Complication Openface feels almost routine, at least by the standards of Vacheron Constantin’s elite division, named after the sun-filled watchmaking ateliers of the past.

What qualifies as a routine event for a manufacture with Vacheron Constantin’s level of expertise? In this case, its engineers have “simply” revealed the inner workings of a movement that brings together three rarely combined complications: a split-seconds chronograph, a minute repeater, and a tourbillon.

It must be said, this new iteration is significantly more striking than its predecessor, the Les Cabinotiers Minute Repeater Tourbillon Split-Seconds Monopusher Chronograph unveiled at Watches and Wonders 2022, which featured a traditional closed dial. Now, the secrets of the manually wound Calibre 2757 S are on display.

Comprising nearly 700 components, the movement offers a power reserve of 58 hours.The multi-layered movement, with its openworked components finished to perfection (requiring twice as much time to decorate as to assemble) appears remarkably modern when compared to its more understated predecessor.

The exposed elements are complemented by frosted sapphire crystal subdials and green accents throughout: the minute track, central chronograph hands, and the hand of the 30-minute counter all echo the tone of the green alligator leather strap.

The calibre stands out for featuring a spherical balance spring within the tourbillon, a perfect match for a split-seconds chronograph housed beneath the dial. The extra vertical space required for the spherical spring naturally complements the volume needed for the chronograph mechanism, and vice versa.

A variant of the cylindrical spring, the spherical hairspring has been used in previous Les Cabinotiers models, such as the Armillary Tourbillon. Its primary function is to enhance chronometric performance: the spherical shape allows for more concentric “breathing”, which improves isochronism and reduces positional errors.

The movement, measuring 33 x 10.4 mm, is housed in a polished pink gold Traditionnelle case. Given the technical complexity, its substantial dimensions – 45 mm in diameter and 16.4 mm thick – feel entirely justified. The Vacheron Constantin Les Cabinotiers Temporis Duo Grand Complication Openface produced as a piece unique.