-Introduced at Basel World in 2004, the Grande ChronoMaster XXT Tourbillon marries Zenith’s legendary high-frequency El Primero chronograph with the sophisticated precision of a one-minute tourbillon regulator to create a breathtaking union of speed and finesse.

-At the heart lies Zenith's landmark El Primero movement, undisputed as the world's only high-beat chronograph ticking at 36,000 vibrations per hour for accuracy to 1/10th of a second. Paired with this is haute horlogerie's ultimate complication - the tourbillon, placing the escapement in a rotating cage to offset gravity's effects. To combine the two seems to defy the laws of kinetics, as the tourbillon draws energy from the chronograph potentially slowing its velocity. Yet Zenith's talented engineers and watchmakers spent three years perfecting the impossible.

-The resulting achievement maintains the El Primero's high-frequency while still powering the tourbillon for optimal energetic equilibrium. A second ingenious patent emerges - the calendar disc spins opposite the tourbillon, changing the date instantaneously at midnight as the carriage revolves in 60 seconds. A double helix of mechanical mastery.

-In a nod to accelerated progress, the very concept of the tourbillon embodies an upward spiral, disrupting the linear cadence of time. Accordingly, the Grande ChronoMaster XXT Tourbillon's design is boldly asymmetrical, with an off-center hour axis and markers that crescendo toward the carriage at 11 o'clock. With a resolutely modern aesthetic in white gold and black, the present timepiece encapsulates both tradition and boundary-pushing advancement.

-Driven by 319 parts animating the remarkable cal. 4005, the watch carries visual intrigue to match its technical brilliance. A canvas for Cartesian minds yet also seducing the heart with its beauty and motion, the present well-preserved example numbered 04 of a limited edition of 50 pieces and further accompanied by its original accessories represents Zenith's ultimate ingenuity and artistic flair.