es Cabinotiers is a department in its own right within the Manufacture Vacheron Constantin, dedicated to creating single-piece editions. Following in the footsteps of the Geneva master-watchmakers known as cabinotiers in the Age of Enlightenment, the team took up the challenge of giving substance to the dream of a passionate collector who wanted a pocket watch that was technically and aesthetically exceptional, reflecting the noblest traditions of 18th century Haute Horlogerie.

Stemming from over 266 years of expertise and eight years of development, the Les Cabinotiers Westminster Sonnerie – Tribute to Johannes Vermeer pocket watch embodies art and beauty, exceptional mechanics and technical mastery. This creation fulfils the most secret expectations of a collector for whom "passion consists in always seeking that which is theoretically impossible to obtain”, a collector whose love for single-piece edition led to this project involving eight years of cooperation with Vacheron Constantin. This adventure, brimming with challenges, research and constant exchanges, has given rise to a veritable masterpiece of Haute Horlogerie.

The Les Cabinotiers Westminster Sonnerie – Tribute to Johannes Vermeer pocket watch is powered by a new 806-part manual winding calibre, regulated by a tourbillon and comprising Grande and Petite Sonnerie Westminster chimes, coupled with a minute repeater.

Within the range of watchmaking complications, Grande Sonnerie models have always enjoyed a special aura, not only because of the inherent complexity of these mechanisms striking several gongs, but also because of the musical qualities required.

Grande Sonnerie watches have a centuries-old tradition within the Maison. Among the oldest timepieces preserved to date, the first travel clock housing such a complication dates back to 1820. When it comes to pocket watches, the oldest model with Grande and Petite Sonnerie in the Vacheron Constantin private collection is dated 1827. It was followed by several timepieces equipped with such mechanisms, some of them representing landmark creations endowed with an array of extremely sophisticated complications, such as the “Packard” presented in 1918 or the King Fouad I watch completed in 1929. More recently, the world’s most complicated pocket watch, Reference 57260, was presented in 2015 on the occasion of the Maison’s 260th anniversary, affirming the expertise of the Maison in the realm of exceptional watchmaking.

"I had long dreamed of having a real Westminster chime pocket watch in my collection striking five gongs with five hammers, featuring a Grande and Petite Sonnerie and adorned with miniature enamel.” Such was the thinking of the client who commissioned this model, leading to the creation of Calibre 3761 measuring 71 mm in diameter and 17 mm thick. It is regulated by a tourbillon majestically enthroned on the lower part of the movement, visible through the caseback and performing one full revolution per minute.

The tourbillon is driven by a 2.5Hz balance (18,000 vibrations per hour). The Westminster chime with which the movement is equipped with one of the most complicated striking mechanism to build, as it requires a sequence of five gongs struck in perfect harmony by their respective hammers controlled by four racks. In wristwatches, Grande Sonnerie (grand strike) mechanisms are usually operated by a single rack, mainly for reasons of miniaturisation. The four rack and snail solution, with four racks for the hour and quarter chimes and one rack for the minute repeater, enhances the sequencing of the melodies and, as an added subtlety, enables different melodies to be played when passing the quarters.

The term ‘Westminster chime’ refers to the world-famous bells of Big Ben, the British Tower of Parliament in London: a four-bar melody consisting of four notes played at different frequencies. In “Grande Sonnerie” mode, the watch chimes the quarters in passing, with the hour repeated at each quarter, meaning three bars of the Westminster melody followed by five single notes for 5.45 am. In “Petite Sonnerie” mode, it strikes the quarters at each change of quarter without repeating the hours; and at each change of hour, it strikes the fourth quarter – “the carillon” – as well as the hours. The strikework can be activated at any time by means of the slide on the side of the watch. The watch then functions as a minute repeater that chimes the quarters, minutes and hours in sequence. The selector switch positioned at 9 o’clock thus offers three possible modes.

In “Sonnerie” (strike) mode, the watch is automatically activated each time the quarters change, like a clock. In “Night Silence” mode, a special feature specifically developed and adapted to this 3761 calibre according to the time zone chosen by the customer, the alarm is deactivated between 11 pm and 9 am, thus saving energy as well as ensuring peace and quiet at night. The third and last “Silence” mode completely suspends the striking mechanism. A second selector, positioned between 10 and 11 o’clock, serves to switch from Grande Sonnerie to Petite Sonnerie as preferred. The two barrels ensure an autonomy of approximately 16 hours for the musical mechanism in “Grande Sonnerie” mode and 80 hours for the time indications, with stable torque guaranteed until the end of the power reserve.

Calibre 3761 is equipped with a centripetal strike governor ensuring perfect regularity of the musical sequences, of which the notes must be both distinctly audible and pleasing to the ear. The system is characterised by a pair of weights whose very special shape has been optimised so as to generate a kind of “engine-braking effect” – by centripetal force – on the regulator’s pivot axis, thereby evening-out the energy released by the barrel. This unique and original device is also perfectly silent. In another special feature regarding the flow of time, the calibre houses a double-wheel system with clearance adjustment. Given the size of the hands, in order to avoid any potential jerking of the seconds hand positioned at 6 o’clock, such a mechanism ensures its smooth flow thanks to a system based on two coaxial toothed wheels linked by a spring serving to eliminate gear play.

Representing the sum of rare talents, this Les Cabinotiers model demonstrates high standards and attention to detail in terms of movement finishing. All the components are thus hand-finished – from the completely engraved balance bridge to the bridges buffed with diamond paste to achieve a mirror-polished finish, as well as the galvanic treatment of the plates adorned with Côtes de Genève and featuring a soft champagne colour – creating an overall effect evoking the noblest watchmaking traditions.

The work on the ratchet wheel and the two barrel wheels is an excellent example of these meticulous tasks. The wheels first underwent surface treatment in the form of sandblasting and then sunburst finishing, before the teeth were glazed on all five gear portions. This type of finishing consists of chamfering the teeth and giving them a mirror-polished finish on the flat parts, a skill formerly used in watchmaking and that the Maison is committed to preserving. A week of patience and meticulous care was needed to decorate these three components.

The tuning of the gongs also requires a perfectionist’s spirit. First tested before being cased-up, they are shaped in such a way as to obtain the right note for each of them. This inevitably requires touching up with a file to achieve a perfect sound. There can however be surprises once the chiming mechanism is cased up. On this model, two of the five original gongs had to be replaced for the sake of harmony. By modifying the steel alloys, the sound of the two new gongs acquired a more crystal-clear entirely in tune with the other three.

This “tuning” of the Grande Sonnerie thus requires several successive casing-up procedures, since the mechanism has to be removed for any adjustments during the “trial runs” of the mechanism. These are indeed not the only elements of the assembled movement that undergo retouching during these various phases, which is why the latter take place even before the case is decorated. An additional difficulty with this single-piece edition was that it was impossible to case up the entire finished movement and part of the final assembly had to be done directly inside the case.

Given the level of finishing and decoration of each component, including the case, as well as the fact that any handling manipulation could potentially impair the quality, the ten operations involved in fitting the calibre – which had to be removed the same number of times for retouching – followed by the final assembly required an uncommonly deft touch. In the end, a very small team of specialised watchmakers conducted the making of this Calibre 3761, from the development, manufacturing and finishing of the various components to the final assembly and casing-up of the movement.

The officer-type caseback cover features a miniature enamel painting, finely crafted using the Geneva technique and reproducing the Girl with a Pearl Earring, a work by Dutch painter Johannes Vermeer dating from 1665. Above and beyond the challenge of reproducing the work of a great master, an additional difficulty lies in the small size of the 98 mm-diameter support. The case sides are graced with hand-engraved friezes composed of acanthus leaves and tulips, accompanied by a “pearl” rim, while the bow is adorned with two roaring lion heads carved from a block of gold.

Stemming from over 266 years of expertise and eight years of development within the Les Cabinotiers department, the Les Cabinotiers Westminster Sonnerie – Tribute to Johannes Vermeer fulfils the expectations of a collector for whom "passion lies in always seeking that which is theoretically impossible to obtain.”