Hands-on with the 2020 GPHG winner for Calendar and Astronomy- Vacheron Constantin Overseas Perpetual Calendar Skeleton

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The Vacheron Constantin Overseas Perpetual Calendar Ultra-thin Skeleton was awarded the “Calendar and Astronomy” prize at the Grand Prix d’Horlogerie de Genève (GPHG) 2020. This watch was unveiled in the Watches & Wonders earlier this year. The watch arrived in Singapore for a photography session, and we got up close with it. This is our detailed hands-on review with our original photography.

Vacheron Constantin Overseas Perpetual Calendar Ultra-thin Skeleton Ref. 4300V/120R-B547

The REFERENCE: 4300V/120R-B547 is a boutique exclusive model. Price on application. The non-skeleton version, REFERENCE: 4300V/120R-B064 has a retail price of S$141,000.

Though this photograph was taken on October 27, 2020, way before the GPHG, we already thought it was a winner by posing the VC Overseas Perpetual Calendar Ultra Thin Skeleton with a winner’s cup.

Earlier variants

Vacheron Constantin Overseas Perpetual Calendar Ultra Thin Ref: 4300V/000R-B064  2019Essentially the same watch, but not skeletonized dial or movement. A gold bracelet version Ref. 4300V/120R-B064 is the non-skeleton also released in 2020.

Vacheron Constantin Overseas Collection (2016)The start of the Overseas collection included the Perpetual Calendar Ultra Thin, but released in 18k WG. No skeletonization of dial or movement is offered. No bracelet option in 18k.

The Overseas Ultra Thin Perpetual Calendar Skeleton is also the first skeleton watch in the Overseas collection.

The case, dial and hands

The case is the standard Overseas case, but crafted in pink gold. In the metal, the case feels remarkably thin, especially even more for one which houses a perpetual calendar which is wound automatically. The case finishing is excellent, with brushed surfaces contrasting nicely with the brightly polished chamfered sides. The bezel is characteristic of the Overseas and bears the signature 6 tooth cogwheel design. The entire bezel is polished to a high gloss.

The bracelet design follows the same blueprint as those in the steel Overseas watch. But is now crafted in pink good. The interlocking links bear hints of the malteze cross, and also carry over the theme of alternating brushed and polished surfaces. This creates a rather beautiful visual. As with the other bracelet Overseas model, the Perpetual Calendar Ultra Thin Skeleton is shipped with 3 straps – in blue rubber/silicone with a pink gold deployant buckle, in crocodile with a pink gold pin buckle, and with the solid gold bracelet. The impressively easy release and attachment system is retained.

The dial itself is sort of vestigial, as skeletonized models tend to be. What remains after the removal of the dial proper is a chapter ring marking the minutes – with 5 minute intervals marked in a blue arabic print, separated by minute markers in black painted strokes. The hour markers themselves are a cantilevered extension of this chapter ring, reaching into the center of the mainly open dial. The markers are finished in pink gold with infilled Superluminova. The sub-dials for the perpetual calendar markers populate the center 4 positions, spread out equally at 12, 3, 6 and 9 o’clock positions. Of particular note is the moonphase dial at 6 o’clock, which not only bears the moonphase display, but shown over a frosted glass screen bearing the Malteze Cross logo in appliquè and the brand name “Vacheron Constantin Geneve” in two lines pf black print.

Though the entire lot of perpetual calendar information is squeezed into the other 3 sub-dials, the layout is quite logical and legibility though compromised by the busy dial, can still be read rather easily. The use of a four year month sub-dial simplifies the display for leap years shown in blue print over black for the non-leap years. This arrangement does make the sub-dial more crowded, as it will need to show all 48 months, but avoids adding a leap year indicator. The date is only displayed as arabic numerals for the odd dates, with the even dates marked as dots. Subjectively, though, we feel the layout does not make the dial look congested, but retains a rather pleasant, though complicated look.

Calendar corrections are done via pin buttons at the case side. This is the traditional in every way.

Finishing of the case, dial, hands and bracelet is superb, as one might expect from VC.

The movement VC Caliber 1120 QP SQ

Beating inside the Overseas Perpetual Calendar Ultra Thin Skeleton is the VC Caliber 1120 QP SQ. This is an interesting movement, with a checkered history.

The base movement is the caliber 920 introduced by Jaeger-LeCoultre in 1967. This is an ultra thin automatic movement measuring just 2.45mm with a full size rotor, and was developed by Jaeger-LeCoultre for Vacheron Constantin, Audemars Piguet and Patek Philipe. It appeared as the Patek as the caliber 28-255 in the (original) Ref. 3700 Nautilus, and as the caliber 2121 in the Royal Oak. While Patek has gone in-house with the development of the Caliber 335 SC used in the Ref. 3800 in 1980 and the 315 SC for the 5711 later, VC and AP acquired the rights to continue production of the C.920 in their own manufactures. In the C. 1120 QP, Vacheron has inserted their own in-house perpetual calendar module, and in the QP SC version used in the review watch, further developed to skeletonize the movement.


1120 QP SQ. VC photo.

Movement finishing is typical of VC. Which is to say it is consistently excellent, with all the hallmarks of a top tier haute horlogerie model. The inclusion of many acute inward and outward angles is a case in point. The Malteze cross on the rotor itself has 24 inward pointing angles, each expertly executed.  Also visible on the case back is the Poinçon de Genève hallmark.

With the dial side exposed, and protected by glass, the movement finishing needed to be just as perfectly done on both sides.

The competitive landscape

Skeletonized watches are a special breed. And even more special are skeletonized perpetual calendars. We think the rarity of such specimens are perhaps due to the large quantity of information needed to be displayed on a perpetual calendar, and skeletonizing that makes the dial too difficult to read.

While not a model of legibility, the Overseas Perpetual Calendar Ultra Thin Skeleton  is still rather easy to read,. Though not in a hurry…but then when does one need the full perpetual calendar information in a jiffy? Probably not. In the dark, the lume components on the hour and minute hands and the hour markers make the time reasonably easy to read, though truth be told, the lume is just about good enough to make out the time, and not about to win any lume contests. We leave that to specialized watches. Read our Lord of the Lume article for suggestions for those, but none of the recommended watches are anywhere near the finesse offered by VC.

So perhaps it remains that Audemars Piguet offer some form of rivalry in this very specialized landscape. Both the AP Code 11.59 ( no skeletonized version available. The standard pink gold with adventurine dial is offered at S$110,800) and the Royal Oak offer a Perpetual Calendar built over the same JLC C.920 base. But only the RO is available with a skeletonized version (POA), and that a boutique exclusive only in a black ceramic.

Concluding thoughts

The Overseas Perpetual Calendar Ultra Thin Skeleton is a remarkable watch. When we first encountered it, we never thought we would fall so deeply in love with the concept and execution. But we did. Deeply head over heels! For a traditional perpetual calendar with skeletonizing, this is quite as near perfect as we could ever imagined. The watch brings to it a quiet presence that many VC watches achieve.

The words of Theodore Roosevelt’s foreign policy: “speak softly and carry a big stick” seem to resonate well. The virtues of a manufacture like VC is evident. The execution speaks of the finesse and elegance expected of the Grand Old Dame. The concept is so beautiful and magnificent. And the final product is impressive indeed.

Vacheron Constantin Overseas Perpetual Calendar Ultra-thin Skeleton Technical Specifications

Reference 4300V/120R-B547

1120 QP SQ/1
Developed and manufactured by Vacheron Constantin
Mechanical, self-winding
22K openworked oscillating weight in the shape of a Maltese cross
NAC treatment
29.6 mm (12½’’’) diameter, 4.05 mm thick
Approximately 40 hours of power reserve
2.75 Hz (19,800 vibrations per hour)
276 components
36 jewels
Hallmark of Geneva certified timepiece

Hours and minutes
Perpetual calendar (date, day of the week, month, leap year)
Moon phases

18K 5N pink gold
41.5 mm diameter, 8.1 mm thick
Soft iron casing ring ensuring anti-magnetic protection
Transparent sapphire crystal caseback
Water-resistance tested at a pressure of 5 bar (approx. 50 metres)

18K 5N pink gold hour-markers and hours & minutes hands highlighted with white luminescent material

18K 5N pink gold bracelet (half Maltese cross-shaped polished and satin-brushed links), secured by a 18K 5N pink gold triple-blade folding clasp with push-pieces and comfort-adjustment system
Delivered with a second strap blue Mississippiensis alligator leather featuring a blue nubuck lining, with a micro-perforated effect, hand-stitched
Delivered with a third strap in blue rubber

Each additional strap comes with an 18K 5N pink gold buckle


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