Overseas Grand Complication Openface: Technical Excellence

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Equipped with Calibre 2755 QP, the new Overseas Grand Complication Openface achieves a horological feat as an elegant sports watch housing a movement barely 7.9 mm thick and incorporating a minute repeater, a perpetual calendar, a tourbillon and a power reserve indicator. With its water-resistant titanium case and integrated bracelet, this grand complication model respects the technical and aesthetic codes of the Overseas collection. The sapphire dial reveals the beauty of the mechanism, while rhodium-plated wheels and NAC treatment enhance its avant-garde spirit. Vacheron Constantin’s attention to detail is exemplified by the meticulous care taken in the hand-finishing of the movement components.

Haute Horlogerie prowess

The Vacheron Constantin Overseas Grand Complication Openface is the outcome of a long process to meet the challenge of integrating a grand complication mechanism into an elegant case. In addition to a tourbillon and a perpetual calendar, this movement incorporates a minute repeater, a first in the collection. Generally speaking, water resistance is difficult to achieve with minute repeater calibres due to the sliding mechanism in the case-side that activates the repeater. The challenge with this model was to ensure the water-resistance of the Overseas case, while adapting its lines to Calibre 2755 QP. This required a year and a half of research and development and involved a complete redesign of the caseback to create space for the minute repeater mechanism while maintaining the slender curves characteristic of Overseas watches. With a diameter of 44.5 mm and a height of 13.1 mm, the proportions of this new Overseas case deftly balance the collection’s adventurous character with a spirit of elegance.

An emblematic calibre

One of Vacheron Constantin‘s emblematic movements, Calibre 2755 QP benefits from developments made for the Tour de l’Île watch presented in 2005 and brings together three major horological complications. With its 602 components contained within a diameter of 33.30 mm, it incorporates a perpetual calendar with date, day, month and leap-year cycle indications. In addition to this calendar mechanism, which requires no correction before 2100 – a non-leap secular year – there is a minute repeater.

To govern the cadence of the repeater mechanism, which strikes the hours, quarters and minutes on demand, the Maison‘s watchmakers developed a centripetal regulator, a proprietary device that allows the hammers to be struck at the precise intervals required to obtain the correct musical sequences. Totally silent, this regulator features two centrifugal weights that act as a motor brake on the axis of rotation, smoothing the flow of energy released by the repeater spring.

In keeping with Vacheron Constantin‘s attention to detail, particular attention has been paid to the aesthetics of this governing device, which is visible through the sapphire caseback. An arc-shaped bar secures the regulator; crafted in 750/1000 gold its rounded form requires a full day of meticulous hand-polishing. Beneath it, the circular-grained inertia weights are engraved with the initials of Jean-Marc Vacheron, who founded the Maison in 1755.

The same high standards were applied to the finishing of the tourbillon bridges, which involved rounding the convex profile as well as tapering it towards the fixing screws, then hand-polishing each bridge to a perfect shine. Their architecture was also reviewed, particularly on the reverse side, where it has been made more open and visually lighter. This allows full appreciation of the tourbillon’s ballet, which is enhanced by the relatively slow tempo of 18,000 vibrations per hour (2.5 Hz). Commensurate with the complexity of Calibre 2755 QP, the movement finishes also include mirror-polished repeater hammers, bevelled and satin-brushed bridges, circular satin-brushed wheels, and bridges decorated with Côtes de Genève.

A sporty and contemporary aesthetic

With its grade 5 titanium case and integrated bracelet, the Overseas Grand Complication Openface watch remains true to the spirit of the collection. Its sporty, contemporary character is enhanced by the transparency of the sapphire dial, which reveals the beauty and complexity of the movement. Applied to the transparent sapphire, the 18-carat white gold hour-markers appear to be floating in space, amplifying the airy aesthetic.

To enhance legibility and create a dynamic contrast with the grey and silver tones of the movement components, the circles surrounding each of the time and calendar indications are treated with a blue metallised finish. The surface of each metallised circle is then engraved in white with the various indications – dates, days, months, years and minutes.

Viewed through the sapphire dial the avant-garde spirit of the watch is highlighted by the contrast between the anthracite grey hue of the NAC galvanic treatment on the bridges and the silvery tone of the rhodium-plated wheels. The mix of finishes on the case and bracelet amplifies the contemporary aesthetic with a visually captivating play of light and reflections. On the bezel, sandblasting combines with polishing and satin-brushing – a new signature for titanium-cased models in the Overseas collection. Like the other pieces in the collection, the model’s titanium bracelet, fitted with a comfort system, is interchangeable without tools and two additional straps – one in blue alligator, one in blue rubber – are offered with the watch.

Questions for Christian Selmoni, Director of Style and Patrimony

Is the openface concept new to Vacheron Constantin or is it part of the Maison’s patrimony?
Vacheron Constantin has a long tradition in this area. The Maison made a name for itself in the 1920s, at the height of the Art Deco period with some extremely elegant openface pocket watches in platinum and rock crystal. More recently, the Twin Beat Perpetual Calendar Openface in 2019, the Traditionnelle Complete Calendar Openface in 2021 and the Traditionnelle Tourbillon Retrograde Date Openface in 2023 have continued this tradition. And let’s not forget the one-off pieces, like the Les Cabinotiers Armillary Tourbillon Rolls-Royce model and the Traditionnelle Openface models launched at Watches and Wonders 2025.

Does the openface concept present any particular aesthetic challenges?
When we create complex movements such as Calibre 2755 QP, it is only natural to want to reveal their full beauty, not just through a sapphire caseback, as is usual, but also by opening up the dial. This aesthetic, which is considered avant-garde because of its kinetic aspect, imposes its own demands. When the dial is openworked the calibre is visible from the front, so we need to apply galvanic or PVD (physical vapour deposition) surface treatments to the movement components to give them colours that fully respect the avant-garde spirit. Another challenge concerns the sapphire crystal dials. As they are also used to display functions, they require delicate machining with several openings, not to mention metallisation and finishing. In this sense, the very notion of openface adds an extra level of complexity.

Does a watch as complex as this Overseas Grand Complication Openface model really have a place in a collection designed for exploration?
With the boundaries between watchmaking genres becoming increasingly blurred today, the world of horological complications is no longer confined to fragile, museum-quality timepieces – far from it. This is exactly what Vacheron Constantin is doing with the Overseas collection. Conceived as a watch with a spirit of exploration adapted to the adventures of everyday life, with useful complications such as a chronograph or dual time-zone display, the Overseas also knows how to go beyond those boundaries. The collection already includes tourbillon and ultra-thin skeletonised perpetual calendar pieces that in no way detract from it – quite the contrary. Each of them is faithful to the Overseas spirit, respecting its codes while adding a new dimension to the world of complications, one of Vacheron Constantin’s great areas of expertise. The same is true of this new Overseas Grand Complication Openface. It is equipped with a complex calibre but in a form that honours the collection’s adventurous character.

Can you tell us more about the reasons for choosing this particular calibre?
We chose Calibre 2755 for this new watch because of its level of complexity, combining a tourbillon, a perpetual calendar and a minute repeater that incorporates the latest development in regulating the striking mechanism. In developing the movement, we benefited from the research behind the creation of the Tour de l’Île, the 250th anniversary timepiece that featured 16 complications. Another advantage of this calibre is its slimness for such a level of complexity – just 7.9 millimetres. What’s more, the movement is modular, allowing the addition of astronomical and other functions, as illustrated by the Les Cabinotiers Grand Complication Bacchus watch of 2022 and the Les Cabinotiers Dual Moon Grand Complication presented the following year.

Vacheron Constantin Overseas Grand Complication Openface Technical Specifications

Reference 6510V/110T-128C – Limited production, price upon request.

Indications

Hours and minutes
Small seconds on tourbillon
Minute repeater
Perpetual calendar (day, date, month, leap year)
Tourbillon
Power reserve on the back of the watch

Movement

Calibre 2755 QP
Developed and manufactured by Vacheron Constantin
Mechanical manual-winding
33.9 mm diameter, 7.9 mm thick
Approximately 58 hours of power reserve
2.5 Hz (18’000 vibrations/hour)
602 components
45 jewels
NAC finishing
Hallmark of Geneva certified timepiece

Case

Titanium grade 5
44.5 mm diameter, 13.1 mm height
Transparent sapphire crystal caseback
Water resistant tested at a pressure of 3 bar (approx. 30 metres)

Dial

Sapphire crystal with blue display counters
18K white gold (750/1000) hour-markers and hours & minutes hands highlighted with blue Super-Luminova®
18K white gold (750/1000) counter hands

Strap

Titanium grade 5, satin-finished and polished, interchangeable and with comfort-adjustment system
Two additional straps, in blue alligator and in blue rubber

Buckle