It took prodigious feats of miniaturisation to develop and ensure the faultless, high-precision operation of this elaborate construction within such a small space. It also required the skills of the most experienced watchmakers in the Manufacture to assemble and adjust to perfection the 459 parts of the new self-winding Vacheron Constantin Caliber 3500 – some of which, such as the tiny springs, measure just 3/100ths of a millimetre. 

For the first time in the range of Manufacture Vacheron Constantin calibers, this self-winding movement with its 51-hour power reserve is equipped with a remarkable peripheral oscillating weight. Mounted on ball bearings, this unusual construction provides a perfectly clear view of Caliber 3500, entirely hand-decorated in keeping with the noblest watchmaking traditions. This peripheral structure also serves to preserve the exceptional slimness of the world’s thinnest self-winding split-seconds chronograph movement. To signal its membership of an exclusive series dedicated to the 260th anniversary of the Manufacture, the peripheral oscillating weight of the Harmony Ultra-Thin Grande Complication Chronograph by Vacheron Constantin bears the dedicated scrolling pattern specifically created by the brand’s designers for this occasion. This unusual motif, also known as “fleurisanne engraving” is inspired by the arabesques adorning the balance-cock of the oldest pocket watch from the Maison, signed by Jean-Marc Vacheron in 1755. 

Equipped with a split-seconds function serving to time phenomena starting at the same time but of different durations, the new Harmony Ultra-Thin Grande Complication Chronograph by Vacheron Constantin is the slimmest in its category in terms of both its movement and its case. The first self-winding split-seconds Vacheron Constantin chronograph to bear the prestigious Hallmark of Geneva, this new in-house pays tribute to the aesthetic of the chronographs made for the brand in the 1920s, by reinterpreting the rounded shape and the interior angle bevelling of the bridges – that can only be done by hand – along with gold bushing and drop-shaped jewel surrounds. 

Development work on Caliber 3500 began in 2008, aimed at developing a chronograph movement featuring a traditional kind of architecture, while benefiting from cutting-edge technologies in order to offer reliability, user friendliness and perfect visualisation of the movement aesthetic. This caliber benefits from the numerous advanced features designed by the Manufacture’s development team, including the so-called “friction” technique for the lateral coupling clutch, which serves to reduce a potential jerk of the hand when the chronograph starts running. Another particularly notable breakthrough is the blocking of the rotor when the barrel is sufficiently wound, thereby avoiding excessive tension in the winding spring. The creation of cone-shaped wheels improves the meshing of the wheels, thus giving the wearer the impression of softer, gentler winding. Moreover, the micro-technologies used for cutting the wheels have made it possible to create extremely close-set teeth to improve the engagement of the gear trains. The creation of an ultra-thin non-spherical differential has contributed to maintaining the power-reserve indication, without influencing the movement’s thickness. Finally, the development of a “dragging” chronograph minutes indication reduces the loss in amplitude and thus improves precision. 

Housed in a precious cushion-shaped case made of 950 platinum, Caliber 3500 deserved an exterior to match its excellence. The “shape-in-a-shape” case combining a curving case, a square waisted case middle and a circular bezel creates a sensation of slenderness, while demonstrating an entirely unique and impressive character. The hours, minutes, small seconds at 9 o’clock and power reserve are clearly displayed on a luminous opaline silver-toned dial framed by a deep red tachometric scale. The blue-painted Arabic numerals beautifully match the blued chronograph hands, while elegant leaf-type hands punctuate the hours and minutes. 

Inaugurating the Harmony collection in an outstandingly elegant manner, the new Ultra-Thin Grande Complication Chronograph by Vacheron Constantin expresses the full degree of mastery achieved by the Geneva Manufacture in the art of shapes dedicated to serving horological science successfully blending tradition with modernity.