Published on June 3rd, 2019 | by Daniel Sherman Fernandez


ZENITH DEFY EL Premero Fusee Tourbillon

Since the dawn of precision timekeeping,watchmakers have sought to produce timepieces that offer unfalteringperformance through the use of “constant force”. Zenith reinterprets the fusee& chain constant force mechanism in a modernistic style in the new DEFYFusee Tourbillon. Housing the new El Primero 4805 SK calibre, a manual-windingmovement that follows the DEFY code of avant-garde movement architecture withan open three-dimensional impact, the DEFY Fusee Tourbillon is available in twodistinct editions in Carbon and Platinum.

Upon a first glance, it’s immediately clearthat the DEFY Fusee Tourbillon’s calibre is out of the ordinary. The spokedesign of the bridges is amplified by their bicolor finish, where the topsatin-finished surface is given a black treatment, while its polished sides area lighter grey rhodium tone. The layout of the bridges offers a balanced layoutof the various functions and complications. On the top half of the movement,one can admire the uniquely conceived fusee and chain constant force mechanism.The chain, which consists of 575 individually hand-assembled components,features a bold blued treatment: a first for a wristwatch fusee and chainsystem. On the opposite end at 6 o’clock, a tourbillon cage with an entirelynew construction featuring an off-centered balance wheel makes a full rotationevery 60 seconds. Like the chain, the tourbillon cage is embellished with astriking blue colour, reinforcing the visual effect of the DEFY FuseeTourbillon’s unique moving parts. Positioned at the edge of the dial between 4and 5 o’clock, a red-tipped hand indicates the power reserve, a handy featurewhen manually winding the DEFY Fusee Tourbillon with its 50-hour power reserve.


As a mechanical movement’s mainspringunwinds, the torque it delivers to the regulating organ drops, resulting inless efficient chronometric performance of the movement. A centuries-old solutionto counter this and achieve constant force lies within the power source and itstransmission. Known as the “fusee and chain” system, it features miniaturechain is coiled around a conical “fusee” and attached to the mainspring barrel.As the mainspring unwinds, more of the chain wraps around the barrel, detachingitself from the wide conical base of the fusee. The greater turning movementprovided by the fusee compensates the weakening mainspring pull, thusmaintaining the torque and, consequently, the amplitude of the regulating organconstant throughout the duration of the mainspring’s autonomy.

By combining the fusee and chain mechanismwith a tourbillon regulating organ, Zenith places precision at the forefront ofits unique take on haute horlogerie. Highlighting the unique technical andaesthetic prowess of the piece, the DEFY Fusee Tourbillon is produced in twodifferent editions.

The first version features a light yetrobust carbon case, crown and buckle head. The carbon fibre treatment even extendsto the open dial, with the central skeletal element and surrounding flange ringgiving off the unique shimmer of this material. To complete the high-tech look,the DEFY Fusee Tourbillon in carbon is fitted on a black rubber strap with a“Cordura” fabric effect and blue stitching. A second strap is also supplied, inblack rubber with a woven carbon effect. The DEFY Fusee Tourbillon in carbon islimited to 50 pieces.

The second version of the DEFY FuseeTourbillon, limited to just 10 pieces, is crafted in platinum. The exposedmovement provides a vibrant, voluminous view, where the mix of materials andtones add visual depth, from the anthracite base plate of the movement to theblued chain and tourbillon cage topped with a set of geometrical bridges in twotones. The strap is made of a black rubber core coated with black alligatorleather.

While each version will appeal to adifferent kind of forward-thinking watch aficionado, one thing is certain: theDEFY Fusee Tourbillon solidifies Zenith’s position as a leader in building thefuture of watchmaking.


With innovation as its guiding star, Zenithfeatures exceptional in-house developed and manufactured movements in all itswatches, such as the DEFY Inventor with its monolithic oscillator ofexceptional precision, and the DEFY El Primero 21 with its high-frequency1/100th of a second chronograph. Since its establishment in 1865, Zenith hasconsistently redefined the notions of precision and innovation, including the first“Pilot Watch” at the dawn of aviation and the first serially produced “ElPrimero” automatic chronograph calibre. Always one step ahead, Zenith iswriting a new chapter in its unique legacy by setting new standards ofperformance and inspired design. Zenith is here to shape the future of Swisswatchmaking, accompanying those who dare to challenge time itself and reach forthe stars.

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