The curtain rises on the sixth chapter of Histoire de Tourbillon. This High Watchmaking and High Complication by Harry Winston once again pushes the envelope in both technical sophistication and exclusivity. Its HW4701 caliber is the most complex in the Histoire de Tourbillon series. A genuine first in the history of horology, it combines two independent hour indications: one regulated by a tri-axial tourbillon and the other by a karussel. Both karrusel and tourbillon operate in a similar manner and feature the same exceptional precision-rating qualities. Histoire de Tourbillon 6 is a natural sequel to its five predecessors, with the same immediately recognizable design, that set them apart from any other timepiece. The impressive white gold case is designed to fit the contours and accompany the technical constraints of a movement distinguished by its unique complexity and construction.
The Histoire de Tourbillon 6 movement is composed of two independent parts, like two heads on a single body. Hours and minutes are displayed on one side, regulated by the tri-axial tourbillon. They are recognizable by their color coding – orange against a gray background – and housed within a rounded protrusion on the case. The right side of the watch is distinguished by its blue hands and markings against a black backdrop. It features a dial with hands that can be started, stopped and reset at will. A blue ceramic pusher at 2 o’clock allows this superlative creation to display the elapsed hours and minutes like a chronograph. This unique and versatile function also drives a dual-time display that may be adjusted as desired via the 3 o’clock crown.
The incredible technical sophistication of the tri-axial tourbillon is supremely exclusive. The first cage carries the balance wheel and performs one turn every 45 seconds. It rotates inside a second cage, which spins in 75 seconds along its vertical axis. This ensemble is set in motion inside a third, spherical cage, which completes its own revolution in 300 seconds. The latter is the cage featuring the orange seconds hand, visible beneath a sapphire crystal dome that offers a fascinating view of the three-dimensional ballet of time. Meanwhile, the karussel performs a 30-second rotation.
The varying rotation angles and speeds of the tourbillon and karussel play a decisive role in chronometric performance, which is the watch’s accuracy. Together they counteract the detrimental effects of gravity. Precision is further enhanced by the fast-rotating twin barrels, boasting an exceptionally regular torque.
A few figures highlight the incomparable complexity of this timepiece. Caliber HW4701 is made up of 683 parts. Its tri-axial tourbillon alone requires 141 parts and weighs a mere 1.85 grams. This voluminous graphic structure is visible beneath four sapphire crystals, all distinguished by convex and complex shapes.
The complication that makes the Histoire de Tourbillon 6 unique is a subtle and inconspicuous one. If need be, the karrusel positioned at 1 o’clock can remain idle. When started, it acts as the regulator for the independent part of the HW4701 movement, occupying the right side. It is stopped by default, but starts running when the pusher, located on the caseband is pressed. The specific construction of the karussel means that its balance wheel and its cage are simultaneously linked to the movement’s energy source. Even when halted, they are under constant tension and when released, instantly accelerate to cruising speed. This extremely rare karussel, with a 30-second rotation, operates at high speed in order to occupy a maximized number of positions in space.
With this regulator, time displays can be personalized. The movement on the right side is akin to a monopusher chronograph and replicates that function. Its hands, however, are adjustable via a crown at 3 o’clock. Therefore, they can provide a dual-time display that is accurate to the nearest minute. This rare capability is ideal for offset time zones such as India (UTC +5:30), Caracas (UTC – 4:30) or Katmandu (UTC + 5:45).
Rare, matte-finished and becoming
Despite its exceptional dimensions, 64 mm from crown to crown, Histoire de Tourbillon 6 has a comfortable fit. The mainplate and bridges, forming the structure of the movement, are made of titanium, a metal chosen for its light weight. The case is fitted with ergonomic lugs. Aligned with the large hand-sewn alligator strap, they seamlessly follow the curves of the wrist.
The case is crafted using a white gold alloy with a high palladium content, giving it an attractive glow and radiating a matte sheen that expertly matches the distinctive look of the movement’s surface. It is entirely hand-beveled and sandblasted to give it a granular texture before undergoing an NAC galvanic treatment, which coats it with a black metal layer. The rendering is both sophisticated and striking, and entirely in harmony with the technical nature of the timepiece.
The exclusive nature of Histoire de Tourbillon 6 is amplified by its limited production, a result of the exceptional complexity of Caliber HW4701. As in the previous chapters of the Histoire de Tourbillon by Harry Winston, only 20 will be made.