The focus of Jaeger-LeCoultre’s timepieces for this year hangs on “The Art of Precision”. The theme comes after the integration of the various decorative arts within the maison into one single unit, the Métiers Rares. Where the brand used to develop artistic crafts individually, now they function as a whole. It’s most apparent in the Master Ultra Thin line, which is the bridge between its regularly styled Master line and its higher complication timepieces such as the Duomètre or Hybris Mechanica series. We featured the first release of this year’s highlights in our pre-SIHH edition, showcasing the Master Ultra Thin Moon Enamel. At the fair, the brand revealed two others in the series.

Master Ultra Thin Tourbillon Enamel

The Master Ultra Thin Tourbillon Enamel is one of the three limited-edition timepieces that combine guillochage and enameling on the dial. Using a traditional lathing machine, the sunray guilloché dial is coated with a dark blue enamel and fired up repeatedly, a technique known as flinqué, with up to three repetitions needed to achieve the even tone on the dial.

The calibre 978F is the movement that powers this watch — a reconceived version of the caliber that won the Concours International de Chronométrie years ago with one of the highest results ever achieved in the competition. Maintaining the movement’s performance is a given with Jaeger-LeCoultre’s emphasis on precision, but the dial’s layout is also beautifully balanced, thanks to the work of design director Lionel Favre.

The top half of the watch holds a date subdial that matches the tourbillon aperture at six. The subdial has a circular graining inner ring, with a silver date ring bearing applied numerals. The tourbillon bridge bears a small seconds hand for indication. The multiple finishes on the subdials play against the enameling for a radiance that’s almost opaline-like. Paired with a white gold case that’s polished to a mirror finish, the watch is restricted to just 50 pieces worldwide.

Master Ultra Thin Perpetual Enamel

The third limited edition model within the line is the Master Ultra Thin Perpetual Enamel. The perpetual calendar is one of the most powerful demonstrations of the mathematical precision needed for a mechanical watch to function. After all, most perpetual calendars contain a wheel that has four teeth and only turns once a year. That means watchmakers building a movement like the caliber 878A/2 which drives the Master Ultra Thin Perpetual Enamel must rigorously test this and other parts of the calendar function, to ensure it will work when needed.

The caliber 878 has been reworked and refined for the Master Ultra Thin Enamel series. The date, month and day counters are arranged at the 9, 12 and three o’clock positions for a convenient read of the calendar, with a digital year indicator integrated into the month display. Meanwhile, the moon phase display is enhanced with a double moon phase function, showing both phases of the moon in the northern and southern hemispheres. A display ring and hand are also integrated into the counter, simultaneously showing the phase of the moon as well as the number of days of its revolution around our planet. As a result, the dial has a balance in the use of space that most perpetual calendars tend to lack.

The mix of digital and analogue displays on the dial also makes it a very legible timepiece, despite the amount of information that’s packed into it. To emphasize the space available on the dial, Favre opted to use different textures in the counters to magnify this, with a matte clous de Paris guilloché and a blue ring around the counters. The moon phase indication ring is engraved to enhance the display, and the sandblasted texture has one’s mind referencing the lunar surface when looking at the dial.

One detail that Favre highlights, which many would not realize, is the work that went into the hour indices on each dial. They’ve been lengthened and angled to fit the sunray guillochage, and are designed so they fit the dials exactly. That takes meticulous co-ordination between the master artisans of the Métiers Rares division. The watch is limited to 100 pieces worldwide.

The calibre 868A/2 also features an enhanced power reserve of 70 hours, significantly increased from the 868/1’s 38. Not only has Jaeger-LeCoultre worked on the aesthetics of the collection, it’s also made sure there’s a technical improvement within the watch. It’s not merely precision art, it’s also precision timekeeping.