Ulysse Nardin Classic Skeleton Tourbillon White Gold — Diamond-Set Open Dial | Ref. 1700-129BC

One hundred and thirty-three diamonds set into 18K white gold represent a level of jewellery investment that would dominate most watches. In the Ulysse Nardin Classic Skeleton Tourbillon, they frame a mechanical spectacle so rare and architecturally demanding that the gem-setting serves as the appropriate enclosure for a flying tourbillon movement of exceptional capability. The tension between mineral opulence and mechanical transparency is resolved by the fully skeletonised dial — or rather, the absence of a dial — that allows Caliber UN-170's architecture to occupy the case as an unobstructed view of what Swiss watchmaking at its most technically ambitious actually looks like.

Caliber UN-170 is a manual-winding movement whose 170-hour power reserve stands as one of the most generous specifications in the flying tourbillon category. The figure is not a marketing abstraction but a genuine engineering achievement: more than seven days of continuous operation from a single full wind, delivered by a barrel architecture optimised for energy storage efficiency rather than movement compactness. The flying tourbillon itself — the cage suspended without a bridge above the dial plane, creating the visual impression of a mechanism that defies gravity — rotates at one revolution per minute, its 60-second periodicity serving as both regulator and seconds display. At 44mm, the white gold case provides the internal volume required for this movement without the dimensional excess that would compromise wrist presence.

The leather strap with simple buckle is the correct pairing for a piece of this jewellery register — its understated construction directing all attention to the case and movement rather than the fastening. Water resistance to 30 metres is standard for grand complications in precious metal settings. For the collector who approaches horology as a convergence of the finest gem arts and the highest mechanical ambitions, the Classic Skeleton Tourbillon in diamond-set white gold is Ulysse Nardin's most complete statement of that ambition.