Since its facelift in 2013, the Master Ultra-Thin Perpetual has appeared in various guises, including the sleek black dial version we saw in 2016. However, I think there is unanimous agreement that the 2019 white gold version with its blue enamel guilloche dial wins hands down. Released as part of a limited edition trilogy, including the Master Ultra-Thin Moon Enamel and Tourbillon models, the new members of the Master-Thin Enamel family stole the show. The watch we will be looking at today comes with a revised movement and display and indicates the phases of the Moon in both the Northern and Southern Hemispheres.The Master Ultra-Thin Perpetual Enamel we’re reviewing today is part of a sub-collection of 3 watches (all in limited production), depicting superb enamel/guilloche dials in translucent blue.Realigning the QP functionsLike its predecessor, the case of the new Master Ultra-Thin Perpetual still measures 39mm but is crafted in gleaming white gold and has a slightly thicker profile of 10.44mm (formerly 9.2mm, mainly due to the new dial). But that's about as far as the similarities go. With the changes made to the QP module on top of the famous calibre 868, the arrangement of the perpetual calendar indications has changed radically, swivelled around the dial by 180¡ã. The Moon phase indicator is now at 6 o'clock (more elegant if you ask us), the year and months at 12 o'clock, the days of the week at 3 o'clock, and the date at 9 o'clock. Four sub-dials contain all the pertinent information and bring a pleasing symmetry to the dial. Ad - Scroll to continue with article The only function that has maintained its previous position is the discreet “safety adjustment” indicator located just above the axis of the central hands (when red, you shouldn’t adjust the date with the quickset function, otherwise the movement will be damaged). Worth noting how the needle-thin hour and minute hands feature a small rectangular incision at their base to avoid blocking the view of the safety indicator. Depicted against a midnight-blue sky studded with stars, the silver Moon indicates its current phase in the Northern hemisphere. To find out what the Moon is up to in the Southern hemisphere, you have to consult the silver counter engraved with the numbers 0 – 29.5 on the right side, and on the opposite side symbols of the waxing and waning of the Moon. The hand for this counter has two tips, one points to the numerical age of the Moon on the right, while the second tip of the hand points to the phases of the Moon in the Southern Hemisphere. To celebrate its limited edition status, the hour markers have been reworked and are longer and more refined to reflect the fascinating texture of the dial.An extraordinary dialBlue dials might have saturated the market of late, but it is hard to take your eyes off the absolutely unique aqua-grey-blue colour and fascinating texture of this dial. What makes it so hard to pinpoint the colour of the dial is the way it plays with the light, changing from an almost metallic, electric blue to a darker, more midnight tone of blue. With its very own Metiers Rares (Rare Handcrafts) department on site, Jaeger-LeCoultre is able to produce some of the most extraordinary handcrafted dials (think back to those amazing miniature paintings on the Reverso). The dial of the Master Ultra-Thin Perpetual Enamel combines the art of a hand-guilloche pattern etched on the metal, which in turn is covered with a translucent blue enamel coating.The metal base features a hyper-elegant pleated pattern that tapers towards the centre of the dial. The combination of the cold white gold and the rays of metallic blue light that fan out across the dial produces a mesmerising effect and is probably one of the most elegant combinations I have seen in a long time. To highlight the perpetual calendar information, the sub-dials feature a slightly darker blue circular frame with a different style of guillochage (tiny pyramids) in their interiors, except for the Moon phase indicator that is framed by a silver ring and is nestled behind the same pleated background as the dial. Calibre 868A/2The new alignment of the QP indications on the dial responds to the update performed on the JLC calibre 868, an automatic winding movement with a perpetual calendar, now known as calibre 868A/2. The power reserve has also undergone a generous upgrade and now offers 72 hours of autonomy on a single barrel and beats at 28,800vph. The sapphire crystal caseback reveals the handsome Geneva stripes on the bridges, the bevelled and polished edges, the blued screws, the perlage (circular graining) on the main plate and the openworked rose gold rotor with the brand's logo. The white gold casing ring is engraved with the words Limited Edition and the corresponding number of the watch out of the total production of 100 watches.ThoughtsOne of my favourite watches of the SIHH 2019, the Jaeger-LeCoultre Master Ultra-Thin Perpetual Enamel is a handsome ambassador of what the Grande Maison is capable of producing, on both technical and aesthetic missions. Perhaps the “ultra” adjective could be eliminated from the name of the watch because it is not really an ultra-thin watch. The white gold case and stunning blue guilloche and enamel dial are a radiant combination, and the rearrangement of the QP functions on the dial lends this watch a very pleasing sense of symmetry.Price and availabilityThe Jaeger-LeCoultre Master Ultra-Thin Perpetual Enamel (ref. Q13035E1) comes with a matching blue alligator strap, a DIY interchangeable strap system and a white gold folding buckle. A limited edition of 100 pieces, the Master Ultra-Thin Perpetual Enamel retails for EUR 55,500. Find out more about this watch at www.jaeger-lecoultre.com.