Featuring a two-biaxial tourbillon design, unified by a spherical differential, the new timepiece attains the greatest heights of timekeeping and kinematic magic. With a finish inspired by the world of haute horlogerie, two large tourbillon cages perform a slow ballet with impressive precision. Together, these tourbillons display time through the use of two off-center cones, housed in a large white gold case dedicated entirely to the grand complication. The exclusivity of the Histoire de Tourbillon 8 is matched only by the exceptional quality of its details, finishes, and engineering.

As its name suggests, the Histoire de Tourbillon 8, is first a story of the extraordinary technical prowess of tourbillon timepieces. In an immense space, which encompasses half of the watch, two large tourbillon cages are engaged in a constant dance. Every 75 seconds, each tourbillon completes a rotation on a 30-degree inclined axis. Nested within this movement, a second cage turns on its own axis, completing a rotation every 45 seconds. Within the latter, the balance wheel keeps the tempo at a frequency of 21,600 vibrations per hour.

The principle behind the tourbillon design is to minimize gravity's influence on the balance wheel by enabling it to achieve the maximum variety of positions. With two biaxial tourbillons, the trajectory of its regulating movements is that of a disc inscribed in a sphere. This multiplication of dimensions endows the Histoire de Tourbillon 8 with the highest magnitude of chronometric properties imaginable in a mechanical watch.

Given the rigorous and exclusive environment in which the Histoire de Tourbillon 8 has evolved, the pursuit of such precision must be sought by every available means. This is why the timepiece’s HW4503 caliber is equipped with two rapidly rotating superposed barrels, one of which is equipped with a slipping spring. By virtue of the latter component, there is no sensation of disruption when winding the barrels. Furthermore, the possibility of applying too much tension, which could potentially break one of the three springs, is neutralized. Together, these components guarantee that the watch has a continuous run time of 55 hours, and more importantly, ensures the rigorously calculated regularity to its movement. This quasi-constant flux of motive force maintains the rotation of the tourbillons and balance wheels.

Comprised of 117 components, each biaxial tourbillon weighs no more than 0.76 grams. Each of their two regulating movements operate independently. Nevertheless, they must be unified, so that their deliberately independent mechanical operation results in a single time measurement. To accomplish this, the Histoire de Tourbillon 8 employs a spherical differential. The exceptional complexity of this system makes it possible to obtain an average from the two biaxial tourbillons, eliciting a superlative level of precision to determine the elemental information known as time.

The Art of Composition

The Histoire de Tourbillon 8 is also a story about materials. The materials used in the timepiece have been selected for their technical properties and exclusivity, as well as for their design potential, using only the most exceptional haute horlogerie finishes. The 51 mm case is composed entirely of white gold. It features alternating polished mirror and satin finishes that highlight its various details, such as the three Harry Winston arches located at 3 and 9 o'clock, respectively. The dial, with its chamfers, reveals bevels that encircle the vast space dedicated to the grand revolutions of the tourbillons. The dial’s entire surface area is actually one component, made up of 13 different elements. Its distinctive textural variety is achieved through a manufacturing technique characterized by unparalleled precision, which includes sanded, grained, and satin textures, varnished components, honeycomb patterns, and script produced through a unique engraving technique. Available in 2 color variations, each version is an exclusive 10-piece limited-edition. The first color variation is pure anthracite. The second version features dark gray with intense red accents, which appear on the periphery of the dial, the minute indicator cone, and the bracelet's topstitch needlework.

The HW4503 caliber movement, which is at the heart of the Histoire de Tourbillon 8, is made almost entirely of titanium. This light-weight, rigid, non-magnetic material is difficult to machine, and requires a unique level of expertise to fashion it in accordance with the high level of complexity required by the HW4503 caliber. The titanium used to assemble the plates and bridges first underwent extensive surface treatment, having been sanded or polished in accordance with function, while the edges of each component have been hand-beveled, a time-consuming practice which necessitates a high level of expertise. Titanium was also used to form the three- dimensional bridges which hold the hour and minute indicators in place.

The two conical discs, housing the hour and minute displays, are made of aluminum. Each tourbillon cage is composed of titanium, chosen for its excellent weight to strength ratio. The upper, lower, lateral, and beveled cage surfaces have been embellished by hand, in accordance with the most innovative watch-making techniques. Finally, the bracelet is comprised of hand-stitched alligator leather, featuring red or black needlework that matches the color of the watch dial.

Superlative Complication Ergonomics

The Histoire de Tourbillon 8 is a story of design: a design whose first impression is one of technical prowess, exclusivity, and modernity. At rest, the axial symmetry of the timepiece is nearly perfect. On the left, the two large, superposed, biaxial tourbillons mirror one another. On the right, the two cones, whose masses differ, offset this harmonious effect. Finally, the power reserve indicator, in the form of a grooved scroll positioned at 6 o’clock, restores the timepiece's overall balance. As the tourbillons begin to rotate, their static balance is transformed into mechanical dynamics. The ensuing hypnotic interplay results in a ballet performance that is only visible on the dial’s face, and is reserved solely for the timepiece’s owner and for those invited to witness its choreography. This is because the tourbillons’ backdrop consists of an opaque plate of white gold. This particular feature contrasts with the transparent sapphire crystal case back which reveals the scope of the movement's finishes.

When worn on the wrist, only the Histoire de Tourbillon 8's indicators exceed sleeve-length. Although readability is enhanced, the timepiece remains discrete. Its design is driven not only by technical considerations, but also by the wearer’s needs. The movement's unusual dimensions (43.5 mm diameter) necessitate a sizable watch case. And yet, although the watch case measures 51.0 mm in diameter, it is rather thin: (a mere 17.30 mm). These proportions give the timepiece a relatively delicate and harmonious appearance.

Special attention was paid to lug design, particularly with respect to the lugs’ downward slope. The bracelet, whose geometrical vertical descent from the watch case is nearly perfect, features a clasp which hugs even the most slender of wrists. Such advanced ergonomic research demonstrates that the Histoire de Tourbillon 8 is not intended to embellish a window display or remain locked away in a luxury watch collection. It is meant to be worn, admired, and displayed on the wrist of one of the 20 individuals discerning enough to have chosen it.