Vacheron Constantin sets two records with the introduction of the Patrimony Contemporaine Ultra-Thin Calibre 1731. It is the world’s thinnest minute repeater movement and the world’s thinnest minute repeater wrist watch. This new ultra-thin chiming watch measures just 8.09 mm in height and its movement is just a mere 3.90 mm in height. Even leaving the “world records” out of the equation, what Vacheron accomplishes here is simply magnificent. Striking complications are usually seen as the most difficult of all complications, especially when integrating it in an ultra-thin movement.
For those of you who remember Piaget’s introduction earlier this year, that was also a record for the world’s thinnest minute repeater movement and minute repeater watch. With the difference that the Emperador Coussin Ultra-Thin Minute Repeater is automatically wound, while the Vacheron is a manually wound watch. The new ultra-thin caliber 1731 has been finished to the very highest degree and proudly bears the Geneva seal as proof of this meticulous handwork.
The mainplate is circular-grained, the hammers are black-polished so as to alternately catch the light like a mirror or appear deep black. A time-consuming work that can only be executed by trained hands. The bridges are decorated with a delicate Côtes de Genève pattern with beveled and polished edges. There are seven bridges adorned with this superb hand-finishing, including some with interior angles.
Vacheron Constantin made its first minute repeater on a pocket-watch in 1810, before combining striking mechanisms with other complications. It wasn’t until 1941, before Vacheron Constantin launched its first wristwatch equipped with a single complication, and that was with a minute repeater housed within an ultra-thin movement: Caliber 4261. In 1992 Vacheron introduced another ultra-thin repeater, caliber 1755, measuring just 3.28 mm in height, which is indeed 0.62 mm thinner than the new movement. Because caliber 1755 is not in production anymore, the new caliber 1731 is the world’s thinnest minute repeater movement on the market today. Its name, caliber 1731, is a tribute to the year of birth of the brand founder, Jean-Marc Vacheron.
It was in the 18th century that the first minute repeater watch was devised to provide an audible indication of the time in the dark, in an era before the advent of electric lighting. While this complication is no longer an imperious necessity, it continues to represent the pinnacle of the art of watchmaking. That is because each miniature repeater watch is unique and bears the unique signature of the master craftsman who made it. On demand, the minute repeater sounds the hours, quarter-hours and minutes. After activating the repeater slide – in this case the only element of this major complication visible on the dial side – a hammer strikes the low-pitched gong to mark the hours, while the quarters are played by two hammers on the two gongs – one low-pitched and the other high-pitched – and the minutes are sounded on the high-pitched gong.
As mentioned, the new caliber 1731 is slightly thicker than its predecessor from 1993 – 3.90 compared with 3.28 mm – however it packs no less that 65 hours of power reserve. Caliber 1731 is equipped with a flying strike governor, something that Vacheron Constantin developed in 2007 for the ultra-complicated caliber 2755 (tourbillon, perpetual calendar, power-reserve and minute repeater – see here).
Contrary to classic lever-type governors, this one is completely silent. Its role is to steady the rate at which the hammers strike the gongs. Without a regulator or governor, this musical sequence would take place at the speed of the striking barrel-spring, and would merely produce a rush of indiscernible notes. The device developed by Vacheron Constantin comprises two inertia-blocks or weights designed to act as a brake on the rotating shaft of the governor and thus evening out the energy supplied by the barrel spring. To achieve this, it makes use of two opposing centrifugal and centripetal forces. When the governor spins, the centrifugal force pivots one end of the weights outwards so that the other end presses on the shaft so as to stabilize the rotation speed and thus ensure a steady cadence.
Vacheron Constantin has done everything to ensure the most optimal crystal-clear tones. For starters, the gongs have been connected to the middle case (case band), which amplifies the sound. The entire case is actually designed with a perfect and rich sound as goal, which means an optimal airflow between the mechanism and the case, and much more. The case is even built without joints, so that the elements can interact literally metal against metal and thus enhance the amplitude of the sound.
Not just every watchmaker is capable of building a watch with a striking complication. This art requires gifted hands, lengthy experience combined with infinite patience, as well as a truly musical ear. There aren’t many watchmakers capable of mastering striking mechanisms and at Vacheron Constantin, it requires at least 15 years of experience in the various other workshops, before working for two years under the mentorship of a master. A single watch takes from three to six months to assemble and adjust. Concentration is a must at all times, since one small extra stroke of the file on the base of the gong could muffle its tone.