The tourbillon houses the different elements of the escapement in a mobile cage. It was originally conceived with one specific goal in mind: to increase the watch's operational accuracy by compensating for errors of rate in vertical positions. For Jaeger-LeCoultre, the only tourbillon worthy of its place in the Master Control line was one capable of satisfying the most rigorous demands of a prestigious precision instrument. As such, the Manufacture's engineers made no compromises in creating a tourbillon that answers to the highest possible standards of precision, reliability and strength.

The tourbillon's rotational movement uses up a considerable amount of energy, which is naturally proportionate to the size of its cage. The greater the cage's dimensions, the larger the amount of required energy. Since the energy available in any movement is limited, the solution most commonly adopted by watchmakers is to reduce its frequency as well as the size of the cage, and thus of the balance, which in turn compromises the mechanism's precision. Obviously, such an approach was unacceptable to Jaeger- LeCoultre's master-watchmakers. Instead, they set the challenge of designing an entirely new balance of sufficiently generous dimensions, in order to provide the self-winding movement with the energy necessary to keep the cage in motion and maintain the 28,800 vibrations an hour typical of a high-precision movement. Like every other element in the watch, the new balance, which has an inertia of 11.5 mg x cm2, has benefited from the latest research and development carried out in the Manufacture's own laboratories. Four screws on the balance-selloe are used for the setting. This arrangement ensures constancy, even in the case of impacts to the mechanism. Energy losses owing to friction have also been reduced by the adoption on the gear-trains of Œspyr'-form teeth: these have been specially designed to facilitate a steady transmission of power. The pallet, meanwhile, has been made more compact so that it can fit into the restricted space of the tourbillon's cage. Finally, the movement rewinds in one direction only, in accordance with the results of detailed new research, which suggests that, when a watch is actually worn on the wrist, rewinding takes place twice as fast with a single- as opposed to a dual-direction mechanism.

The perfection of a genuine work of art can be read in even its most minute details. This is certainly true of the Master Tourbillon. The decoration of its movement, visible through the watch's sapphire-crystal bottom, is an aesthetic match for the watch's technical beauty. All delicately hand-executed, the chamfering, drawing, snailing, beading and polishing are worthy ornaments for the Geneva Bars-decorated gear-train bridge.

For the tourbillon's cage, which weighs just 0.28 g, the Manufacture's engineers settled on a titanium alloy: being very light, it naturally increases precision but its hardness makes it difficult to work with. Extraordinary pains — including polished mouldings and delicate sanding — have been taken on the cage. The convex escapement bridge ingeniously connects with the curve of the cage. Manufactured as a single block, the oscillating weight segment and its 22-carat rose-gold support are stamped with a motif in the manner of a medallion, with matt, shiny and chiselled reliefs.

An exceptional timepiece designed for everyday use, each Master Tourbillon has to demonstrate its outstanding qualities of precision, reliability and water resistance before it leaves the Manufacture in Jaeger- LeCoultre's now legendary 1,000 hour test. The latter has been specially adapted to incorporate measurements of the new tourbillon regulator's reliability and amplitude, including when the timepiece is subjected to small impacts and shocks.

The quest for perfection has always been linked to ideals of functionality at Jaeger-LeCoultre. Sheer technical innovation is of little value if it isn't closely allied with the requirements of everyday life. Such considerations have impacted the design of the Master Tourbillon. Driven by a high-frequency self-winding movement, this is a watch that has been created to provide its owner with constant companionship. It is a timepiece for everyday use.

When the fascinated gaze manages at last to detach itself from the circular aperture through which the mesmerising motion of the titanium cage is visible, it naturally settles on the other indicators, arranged in a classic, eye-pleasing configuration on the watch's dial. At this point another aspect of the Master Tourbillon's genius reveals itself, for this is a timepiece that brilliantly harnesses the tourbillon mechanism to the Manufacture's famous home time/travel time principle, a technical refinement that ingeniously makes it possible for busy globetrotters to compare reference time with local time at a single glance. In the upper part of the dial, a 24-hour indicator keeps track of the wearer's reference or home time. This is adorned with a rayonnant motif during the hours when the sun is making its journey across the sky. Here again, the engraving is more than a simple ornament: aesthetic refinements continually transform themselves into functions in their own right on the Master Tourbillon.

The local or travel time, the watch's principal function, is located centrally on the dial. Resetting can be carried out in either direction, both forwards and backwards, in one-hour jumps. The date indicator, which is synchronised with local time, automatically follows, moving exceptionally in both directions as dictated by changes to the local time.

A third central hand, with a double-triangle tip, traces its course around the dial, which is inscribed with the numbers 1 to 31, to indicate the date. It is a classic, simple design of absolute clarity. And yet the watchmakers and designers could not resign themselves to having the date hand concealed, even partially, the movements of the tourbillon when it enters the bottom portion of the dial. They therefore decided to innovate between the 15th and the 16th. So what happens exactly, in the middle of each month, when the hand passes from the one to the other? In fact, it crosses the space at an accelerated rate, in just a few hours. No doubt more than a few Master Tourbillon will linger late on the 15th of the month to gaze in wonder at this astonishing mechanical prodigy.

With the Master Tourbillon, the Manufacture’s master-watchmakers and designers have once more carried precision and functionality to unprecedented new levels of refinement. The second indicator, positioned at the tourbillon’s circular opening, is a good example of this ever-increasing sophistication. While the tourbillon's cage spins vigorously about its axis, the arrow-shaped prong of the blue second hand traces its unending course around the aperture, so combining the measurement of the smallest conventional unit of time with the dazzling spectacle of the most fascinating and complex of all watchmaking mechanisms.

The Master Tourbillon_s classic 41.5 mm-diameter case comes in three different versions: in platinum, in a limited edition of 300; in rose gold and, finally, in steel. For if the Manufacture’s customary deployment of the noblest materials serves to accentuate the extraordinary prowess of its master-watchmakers, such use must also sometimes give way in the face of technical achievements whose unornamented brilliance alone is enough to attract the admiring attention of all.

And now silence must be allowed to fall again. For when all commentaries and explanations have been given, the spirit naturally yearns to be left to contemplate, without distractions, the hypnotic whirling of the tourbillon's cage, which, every minute, makes a full turn about its axis. Fascination is given full rein, the passage of time itself is forgotten and, in the dazzled gaze of the beholder, technical prowess becomes indistinguishable from pure magic.

Movement	:	Self-winding mechanical movement, the Calibre Jaeger-LeCoultre 978, crafted and decorated by hand 28,800 vibrations per hour 48-hour power reserve 302 parts 33 jewels 7.05 mm high monobloc oscillating weight segment cast in 22-carat gold, perforated and decorated with relief engravings
Functions	:	local time with independent rapid setting in both directions (travel time) hand-indicated date synchronised with local time, alterable in both directions 24-hour reference/home time indicator minutes tourbillon regulator with second indicator
Dial	:	steel: silvered, figures and hour-markers in rhodium-plated gold, transferred. 11 luminescent dots 18-carat pink gold: silvered, figures and hour-markers in gilt gold, transferred. 11 luminescent dots platinum 950: gris palladium, figures and hour-markers in rhodium-plated gold, transferred. 11 luminescent dots
Hands	:	hour and minute: Alpha in gilt or rhodium-plated brass, luminescent. Date: gilt or rhodium-plated brass with a blue- or red-glaze double triangle. Reference time: gilt or rhodium-plated brass, blue glaze
Crowns	:	1 crown to start the watch and set the local and reference time, minutes and date
Case	:	ø 41.5 mm in steel, 18-carat pink gold and platinum 950 domed sapphire crystal, hardness N°9 sapphire-crystal base allowing the movement to be viewed water-resistant to 50 metres
Leather strap	:	matt alligator 21/18 and folding buckle in 18-carat white gold, 18-carat pink gold or steel
References	:	platinum 950 165 64 50 18-carat pink gold 165 24 20 steel / leather strap 165 84 20 steel / bracelet 165 81 20

More than any other watchmaker, Jaeger-LeCoultre’s is a culture of complications. Here, in the remote Vallée de Joux in Switzerland, tradition is a sign of life. Today, by imitating the invention of the Manufacture’s great founder, Antoine LeCoultre, Jaeger-LeCoultre’s designers and technicians retrace the paths of their glorious forebearers in their search to develop new masterpieces – the classics of tomorrow. Although they respect the past, their designs in no way lack adventurousness: Jaeger- LeCoultre promotes bold projects, genuine tours de force, involving cutting-edge techniques – a good example being the recently launched spherical tourbillon. In this new movement, the three-dimensional rotations of the balance-wheel are found at the heart of a truly extraordinary piece of horological invention.

Jaeger-LeCoultre timepieces combine complexity with uniqueness. The purity of each watch’s design is the aesthetic counterpart of its technical refinement. The classic ideal is perfectly embodied in the Manufacture’s range of designs. Who is at liberty to say that technology should be subservient to style or vice versa? Jaeger-LeCoultre has exceeded the rules of the old dichotomy which decreed that either style considerations should take precedence over technological ones or vice versa: in the Manufacture’s workshops, technique is translated into art and art is translated into technique – so the two become one.

Time is the only witness of evolution – of the evolution of humankind and of its creations. Jaeger- LeCoultre’s creations illustrate time’s many different faces: minute-repeaters whose delicate chimes fills the sound of silence; chronographs which measure the record-breaking feats of today, that will undoubtedly be surpassed once again; perpetual calendars which make light of the challenge posed by the succession of months and years of unequal length; the Master Geographic which leaps with gracious ease from one time zone to the next. Time is as dynamic as humanity itself. But only a watchmaker of exceptional character can capture each of its different aspects, harmoniously bringing together both technical and aesthetic considerations.

The tourbillon one of the horological complications is an extremely sophisticated device in which the balance-wheel and escapement are housed in a mobile cage which turns on its axis to counterbalance the disruptive effects on the operation of the watch caused movements due to wearing the watch. by the movement of the timepiece on the wearer’s wrist.

Jaeger-LeCoultre is one of the leading producers of wristwatches with eight-day power reserves. The Manufacture has developed a unique device – two barrels mounted in series – to allow sufficient energy to be stored in the watch’s tiny movement, thereby guaranteeing autonomous operation across an eight- day period.

The perpetual calendar is a device of such extraordinary refinement that it even possesses a supplementary wheel dedicated solely to indicating the 29th day of February in leap years. This wheel only returns to its point of departure once every four years.

The Gyrotourbillon 1, driven by the Calibre Jaeger-LeCoultre 177, is the jewel in the crown of many extraordinary complications that have helped forge the brands reputation over more than a century.

Initially designed to be placed inside larger timepieces, the complex movements get smaller in size due to the current trend to miniaturise technological inventions. This miraculous process means even the most highly sophisticated calibres shrink until they fit into the tiny size of a modern ladies’ wristwatch.

The Manufacture’s ability to combine so many different skills is not due to chance, but due to the enterprising spirit of the creative visionary who founded it. Before the love of precision had become a byword for Swiss engineering, Antoine LeCoultre realised that the meticulous attention given to making one of the key parts of the watch – the gearwheel –determined the overall accuracy of the timepiece. He thus invented the first machine for cutting gearwheels and, in 1833, founded his own Manufacture, which rapidly came to embody the new spirit of horological innovation. For the first time LeCoultre gathered together functions that would previously have been scattered across numerous small specialist workshops. Designers of ever more complicated movements were thus able to find all of the skills required to give life to their avant-garde conceptions under a single roof.

The name LeCoultre soon became synonymous with Haute Horlogerie. At the end of the nineteenth century the great Swiss house inaugurated the Era of Complications: split-second chronographs endowed with a double second hand, minute-repeaters, perpetual calendars – not to mention all the different possible combinations of these new complications.

At the dawn of the twentieth century, a collaboration with the Alsatian industrialist Edmond Jaeger at last gave the brand access to the fashionable salons of Paris. Jaeger had an intimate knowledge of the luxury goods market. From then on in the Vallée de Joux horological research allied itself with an awareness of changing social trends and technical refinements began to follow fashion. At this time, the Manufacture established itself as a watchmaking centre of technical master – and remains the same today. In 1925, the Duoplan split the watch movement in two so that it could fit into a narrow case. A few years later, the world-famous Reverso made its debut on the watchmaking stage. This living legend continues to enrich Jaeger-LeCoultre to this day.

In the 1940s, Jaeger-LeCoultre’s unrivalled technical mastery was demonstrated in an official competition at the concours d’Observatoire. The Calibre 170 Tourbillon won the most prestigious prizes at this celebrated event. Beginning in the 1950s, the Manufacture started to explore automation and alarm functions.

In 1987, Jaeger-LeCoultre produced a groundbreaking movement, the Calibre 889/440, which marked a new era in perpetual calendar wristwatch design. Since then the world-renowed Vallée de Joux Manufacture has continued to demonstrate remarkable creativity in the field of round and rectangular wristwatch complications.

Jaeger-LeCoultre’s celebrated Master and Reverso lines continue to be fitted with inspiring and innovative new movements and functions. In the case of the latter, they sometimes appear on the front, sometimes on the back, and sometimes endowed with eight-day movements, perpetuating the tradition of complications with useful functions.

Developing movements with complications represents a technical and aesthetic challenge of the highest order – and never more so than today, in the age of extreme miniaturisation. This is a challenge that the master-watchmakers of Jaeger-LeCoultre meet with relish. They are delighted to make each timepiece - a Tardis-like miniature treasure of huge technical complexity.