Vacheron Constantin’s Les Cabinotiers division – the Maison’s in-house department dedicated to one-of-a-kind, made-to-order creations – has once again raised the bar for haute horlogerie with the unveiling of the Temporis Duo Grand Complication Openface. A single-piece edition, this exceptional timepiece unites three of watchmaking’s most demanding complications – the minute repeater, split-seconds chronograph and tourbillon – in a striking openworked design that lays bare the full complexity and beauty of its inner workings.

At its heart lies the Calibre 2757 S, a hand-wound movement comprising a staggering 696 components. Despite its extreme complexity, the movement measures just 10.4mm thick, a remarkable technical achievement. This is an evolved version of the Calibre 2757, first introduced in a 2022 Les Cabinotiers single-piece edition, now enhanced with a spherical hairspring to further improve isochronism – the consistency of timekeeping as the watch winds down.

This horological marvel is housed in a 45mm pink gold case, fronted by a sapphire crystal openface dial that spotlights the mechanics beneath. The level of finishing is uncompromising, with polished, grained, satin-finished, circular-grained and bead-blasted surfaces reflecting light across every bridge, wheel and jewel. So meticulous is the execution, the finishing alone took twice as long as assembly.

Each complication has been thoughtfully engineered to work in harmony. The split-seconds chronograph, for instance, employs two column wheels – one for the chronograph and one for the rattrapante – which allows the timing of intermediate events by stopping and realigning one of the two central seconds hands. Lightweight aluminium chronograph hands, along with components crafted from titanium, silicon and nickel-phosphorus, help minimise friction and conserve energy. Despite the movement’s complexity, it delivers a 50-hour power reserve even with the chronograph running. Time is recorded to one fifth of a second, with elapsed seconds tracked via the two central hands and a 30-minute counter positioned at 2 o’clock.

Complementing this is the minute repeater, regulated by a silent flying strike governor. This ingenious mechanism ensures the chimes sound at a steady, controlled pace, balancing opposing centrifugal and centripetal forces to modulate the energy released by the repeater’s spring. The result is a rhythmically precise chime sequence, free of mechanical noise. Both the minute repeater and chronograph are activated via side pushers: a single pusher at 2 o’clock handles chronograph start/stop/reset, while a second at 4 o’clock operates the split-seconds function.

Anchoring the movement at 6 o’clock is the tourbillon, a rotating mechanism housed in a cage shaped like Vacheron Constantin’s Maltese cross emblem. Designed to counteract the effects of gravity on timekeeping, it rotates once every 60 seconds. The addition of a spherical hairspring – which expands and contracts evenly in all directions – further improves precision. A small seconds hand is mounted on the tourbillon’s axis.

Visually, the watch is no less impressive. The 0.5mm-thick sapphire dial features both polished and frosted finishes, with 5N gold rings and grey NAC-treated hour markers enhancing depth and legibility. Meanwhile, olive green PVD-coated aluminium chronograph hands echo the tone of the hand-stitched green alligator strap. On the reverse, the movement offers its own spectacle: blackened bridges hand-sandblasted to a fine matt texture, mirror-polished settings for the jewels and screws and a flying strike governor engraved with the initials JMV, a tribute to founder Jean-Marc Vacheron.

As style and heritage director Christian Selmoni explains, this specific trio of complications is ‘very rare in wristwatches, essentially for reasons of volume and precision’. ‘More usually in grand complication wristwatches, we see minute repeaters associated with perpetual calendars. That configuration certainly requires a great deal of expertise, but the chronograph, with its clutch and column-wheel system, is an even bigger issue in terms of miniaturisation,’ he says.

‘This is exactly what Vacheron Constantin wanted to highlight with this watch,’ he adds. ‘The choice of an openworked sapphire dial for this new version of Calibre 2757 was made to reveal and highlight the full complexity of the mechanism, not least the ballet of its tourbillon, which remained hidden in the initial version presented in 2022.’

Indeed, Vacheron Constantin not only overcame those challenges but celebrated them, turning a technical feat into a showcase of mechanical artistry.

POA; vacheron-constantin.com