Three years after the debut of Les Cabinotiers Celestia Astronomical Grand Complication boasting 23 complications, Vacheron Constantin has topped its own achievement at Watches & Wonders 2020 by launching Les Cabinotiers Grand Complication Split-Seconds Chronograph “Tempo”.

Without going into the minefield of what counts as a complication; the new Grand Complication incorporates 24 complications, if each function counts as one – with everything displayed on a massive, two-faced case.

A reversible giant

In addition to showing the time, the Grand Complication includes a minute repeater, tourbillon, perpetual calendar, split-seconds chronograph as well as a number of astronomical indications including equation of time, sunrise and sunset times, plus a retrograde moon phase.

The reverse face

Unsurprisingly, the case is enormous – 50 mm wide and 21 mm high.

But it is intriguingly designed – perfectly symmetrical in profile, the case allows the watch to be worn with either side facing up thanks to a quick-release strap. Swapping faces is a matter of unlatching the strap, flipping the watch over, and reinstalling the strap.

Time, chronograph and perpetual calendar on the front; tourbillon, running Equation of Time, retrograde moon phase and times for sunrise and sunset on the back

Mechanical layer cake

Inside is the cal. 2756, which is derived from the cal. 2755, a movement first found in the Traditionnelle Calibre 2755 grand complication that has since been iterated into even more complicated variants with the addition of modules on top.

In this new Grand Complication, the cal. 2755 grows even more complex and thicker than the already-complicated versions before. Two more movement modules are stacked on the base movement, adding on the chronograph and perpetual calendar respectively, creating a movement made up of 1,163 parts in all.

But despite everything that’s been built on top of the calibre, the cal. 2756 still offers a longish 65-hour power reserve thanks to single but large mainspring barrel.

A module for the cam-driven, astronomical displays (left) that’s mounted on top of the base movement with tourbillon and minute repeater (right)

The back of the base movement with the strikework for the repeater (left) and the split seconds chronograph mechanism that sits on top (right)

The topmost layer – the perpetual calendar mechanism

Functions maximised, readability compromised

Unsurprisingly, the dial of the watch is almost impractically complicated.

The front of the watch is characterised by four registers laid out symmetrically, with the twin central hands being the split seconds hands. It is made up of the time display, chronograph, as well as calendar.

The upper registers are dedicated primarily to the time. The left sub-dial shows the hours of the time, as well an independent adjustable 24-hour scale that can be used as a second time zone. The register on the right displays the minutes of the time, along with the 30-minute counter of the chronograph.

Located at the bottom of the dial are the two registers for the perpetual calendar, with the day and date displayed on the left, the month and leap year on the right.

The back of the watch has all of the astronomical indications as well as the tourbillon, along with a secondary display of the time. Hours and minutes are indicated by a pair of leaf-shaped central hands, while the short, central hand with a sun-shaped tip displays the running equation of time. And a longer serpentine hand indicates the power reserve.

Positioned at three and nine o’clock are fan-shaped scales for sunrise and sunset times, as well as the duration of the day and night. As times for sunrise and sunset are latitude-specific, the mechanism will be calibrated for the owner’s desired city.

Lastly, the bottom of the dial features a retrograde display that indicates the phase of the moon with a pointer, which will be accurate to within a day after a millennium.

Key facts and price

Les Cabinotiers Grand Complication Split-Seconds Chronograph “Tempo”
Ref. 9740C/000R-B692

Diameter: 50 mm
Height: 21 mm
Material: 18k pink gold
Water-resistance: Not water-resistant

Movement: Cal. 2756
Functions on the front: Hours and minutes; minute repeater; second time zone or 24-hour display; 30-minute counter chronograph; split-second chronograph; perpetual calendar
On the back: Tourbillon; retrograde phase and age of the moon; running equation of time; sunrise and sunset time; day and night length; power reserve indication
Winding: Hand-wound
Frequency: 18,800 beats per hour (2.5 Hz)
Power reserve: 65 hours

Strap: Alligator with pin buckle

Limited edition: Unique piece
Availability: Only at boutiques
Price: Upon request

For more information, visit Vacheron-constantin.com.