Vacheron Constantin Overseas perpetual calendar ultra-thin skeleton

The Vacheron Constantin Overseas perpetual calendar ultra-thin skeleton is a technical tour de force. It blends a highly complicated movement, a slender case and an openworked calibre using traditional skeletonising techniques. Few brands would dare to make a watch of such complexity, however, based on its vast experience, this Maison is clearly up to the task.

This year, Vacheron Constantin has been particularly prolific, releasing numerous new watches or ‘novelties’ as they are referred to within the trade. Recently, I wrote at length about one new model for 2020, the Overseas perpetual calendar ultra-thin, a highly technical watch likely to appeal to most self-respecting aficionados.

Another of the firm’s novelties for 2020 shares the same genetic code as the aforementioned watch but presents even more challenges to overcome. Needless to say, the Maison, ‘the oldest watch Manufacture in continuous production’, founded in 1755, has the necessary skill-set to execute the brand’s technical brief.

Vacheron Constantin Overseas perpetual calendar ultra-thin skeleton

The Overseas line is the firm’s sports watch offering, available in noble metals as well as highly practical stainless steel. Having received an extensive update in 2016, range includes mechanical three-handers with a date as well as more technically challenging complications such as perpetual calendars and even a tourbillon. By releasing several new Overseas models of late, Vacheron Constantin is signalling to the world that the Overseas is here to stay for the foreseeable future.

A perpetual calendar is considered a high complication. Using a series of cams and levers, the movement recognises those months with 28, 29, 30 or 31 days, advancing to the 1st automatically without any manual correction. A perpetual calendar can even compensate for leap years. Assuming the watch is kept wound, it will not require manual date adjustment until 2100.

Complexity is usually accompanied by bulk, but the case height of this particular ultra-thin watch is just 8.1mm, the same thickness as its non-skeletonised sibling.

The Vacheron Constantin Overseas perpetual calendar ultra-thin skeleton features the Calibre 1120 QPSQ/1, an openworked movement. These days, most brands selling skeleton watches create a unique movement from the outset as this proves less time-consuming. However, Vacheron Constantin employs a traditional approach, using an existing calibre and then removing material using handsaws. After sawing the sides of the mainplate and bridges, surfaces are drawn out using files to remove any signs of sawing. The artisan needs to know where to remove material, taking care to avoid jewel beds, screws, areas near the gear wheels etc. It is imperative that the rigidity of the movement is maintained and its reliability is not compromised.

Vacheron Constantin Overseas perpetual calendar ultra-thin skeleton

By skeletonising or openworking the movement, it imbues the calibre with a visual lightness, affording views of the finely decorated movement. In this instance, Vacheron Constantin has even openworked the oscillating mass, presenting it in a NAC-treated finish and thereby creating contrast with neighbouring components.

Making a watch of this complexity is not for the faint-hearted, however, Vacheron Constantin has made skeleton watches for many years and its competence is renowned. Indeed, there is no question this venerated Maison is up to the task.

The brand’s press release

In this new gold-clad version, Vacheron Constantin highlights the expression of Haute Horlogerie values. While retaining its dynamic design, the aesthetic of the timepiece is transfigured by a sapphire dial inviting observers on a journey to the heart of the extremely thin 4.05 mm openworked perpetual calendar movement.

Complexity transcending the complication itself

Much appreciated by collectors for its reliability, its extreme precision and its performance, self- winding Calibre 1120 QPSQ is now joining the Overseas collection in a new guise. Entirely openworked, which is a feat in itself, it reveals its mechanical intricacies beneath a sapphire crystal. The transparent caseback also stages a fascinating watchmaking show starring the gear trains and the NAC-treated oscillating weight with its segment in 22K gold, which is also openworked for the first time in the Overseas collection so as to highlight its stylised design shaped like a Maltese cross.

Skeletonisation is regarded by connoisseurs as a watchmaking complication in itself and is indeed a speciality during watchmaking training. This technique, which consists of finely openworking a mechanical movement by hollowing out its components yet without compromising their reliability, is an extremely complex undertaking: a quest for transparency coupled with highly sophisticated skills mastered by very few watchmaking artisans. Today, Vacheron Constantin is one of the rare Manufactures capable of openworking calibres as complex as perpetual calendars and ultra-thin movements. All components of the 1120 QPSQ calibre have been hollowed out, finished and decorated, so as to exalt the functional beauty of the mechanism.

The peak of artisanal watchmaking expertise

To fully match the style of Overseas, the movement has benefited from special finishing work, entirely performed by hand. Multiple skills have thus come into play so as to endow the mechanism with the sought-after aesthetic perfection. Straight-graining the surfaces to give them a satin-brushed finish; bevelling straight lines and curves to make the create light effects; circular brushing, sunburst finishing, circular-graining and polishing to ensure varied reliefs: while the use of all these ancestral craftsmanship techniques has served to highlight the beauty of the components, an anthracite grey shade obtained by means of an NAC electrolytic treatment gives the mechanism a very modern face. The dial bears applied 18K 5N pink gold hour-markers, the Maltese cross emblem as well as day, date and month- counter rings. This design ensures that the watch is perfectly legible while allowing the gaze to roam freely through the heart of the movement and admire its hand-crafted finishing.

Vacheron Constantin Overseas perpetual calendar ultra-thin skeleton

A calendar requiring no adjustment until 2100

While watches with simple calendars – indicating the day, date and month – require constant adjustments according to months with 28, 29 and 30 days, the Overseas Perpetual Calendar ultra-thin skeleton watch will not require any intervention until March 1, 2100. Achieving such a performance with a movement that slim – yet housing 276 components – called for authentic feats of design and miniaturisation.

The freedom of personalisation

Like all models in the Overseas collection, this exceptional watch offers a modular touch via a simple and convenient bracelet/strap interchangeability system. Fitted with a gold bracelet whose satin-brushed half Maltese cross-shaped links underline the elegance of the timepiece, it also comes with two additional straps in blue alligator leather and blue rubber.


Available in an 18K 5N all-gold version, the new Overseas Skeleton Perpetual Calendar watch perpetuates the travel-driven spirit of the collection and combines the refinement of precious metal with the nobility of its ultra-thin openworked complication movement. The 41.5 mm-diameter case houses the prestigious Calibre 1120 QPSQ, which combines an extraordinary aesthetic with Haute Horlogerie values. Greatly appreciated by collectors for its technical qualities and its performance (no adjustment will be required before March 1st 2100, neither for the day, date and month indications, nor for the moon phases), this entirely openworked ultra-thin NAC-treated anthracite grey mechanism is visible through a transparent sapphire dial bearing applied 18K 5N pink gold hour-markers. The transparent caseback also stages a fascinating watchmaking show starring the gear trains and the NAC- treated oscillating weight with its segment in 22K gold, which is also openworked for the first time in the Overseas collection so as to highlight its stylised design shaped like a Maltese cross.

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