The 2026 LVMH Watch Week in Milan serves as the backdrop for a significant shift in focus for the Zenith manufacture, placing the spotlight firmly on the DEFY collection as the primary vehicle for their contemporary horological exploration. Amidst the presentations from sibling brands like Bulgari, Hublot, and TAG Heuer, Zenith has chosen this venue to unveil a timepiece that aggressively pushes the architectural language of its sports-integrated line. The DEFY Skyline Tourbillon Skeleton, Reference 18.9300.3630/78.I001, represents a new pinnacle for the series, marking the first time a tourbillon skeleton mechanism has been integrated into the Skyline chassis. This release is not merely an addition of a complication but a complete structural reimagining of the watch's internal and external geometry, limited to a production run of just 50 pieces worldwide.
The visual impact of this timepiece is immediately defined by the stark, high-contrast interplay between precious metal and industrial coating. The 41mm case is crafted entirely from rose gold, a material choice that provides a warm, substantial frame for the mechanical coldness of the movement within. The geometry of the case adheres to the established Skyline DNA, featuring a sharply faceted octagonal bezel that sits atop the main body. The finishing here is critical to the watch's presence; the surfaces alternate between vertically satin-brushed planes and brightly polished chamfers. This technique is applied methodically across the case flanks and the bracelet links, creating a constant interplay of light that accentuates the angular, architectural nature of the design. The rose gold is not used sparingly; it forms a heavy, robust housing that asserts a luxury status while maintaining the sporty, rugged durability expected of a 10 ATM water-resistant vessel.
Courtesy of Zenith
Dominating the visual field is the El Primero 3630SK calibre, which has been open-worked to such an extreme degree that the concept of a dial is rendered obsolete. In place of a traditional face, the wearer is presented with a web of structural elements finished in an intense blue PVD. This color choice is deliberate, steering away from traditional rhodium or black movement finishes to create a striking, modern aesthetic that Zenith likens to a cityscape. The blue skeletonized bridges and mainplate provide a dark, matte backdrop that allows the moving gold and rhodium-plated components to pop. The architecture is not random; it is centered around a massive, stylized four-pointed star motif—a signature of the Defy line—that seems to radiate outward from the tourbillon cage at the 6 o'clock position.
The tourbillon itself is the kinetic focal point of the lower hemisphere of the watch. Operating at a high frequency of 5 Hz, or 36,000 vibrations per hour, the one-minute tourbillon creates a rapid, frenetic energy that contrasts with the slow, deliberate motion of the hands. The cage is intricate, composed of 56 distinct components, yet it retains an airy lightness necessary for the energy efficiency of a high-beat escapement. The carriage rotates once every 60 seconds, acting as a secondary display of seconds in the absence of a central seconds hand. The design of the cage mirrors the sharp, angular aesthetic of the case, avoiding traditional curves in favor of structural lines that integrate seamlessly with the skeletonized bridges surrounding it.
The upper half of the movement architecture is defined by two prominent bridges located at the 10 o'clock and 2 o'clock positions. These are not flat plates but rather three-dimensional structures with a double-tier, sloping geometry. This design choice adds significant depth to the watch face, creating a topographical relief that mimics the lines and cantilevers found in modern urban skyscrapers. The bridges are treated with the same blue PVD finish as the mainplate but are highlighted with rhodium-plated bevels. These silver-toned chamfers outline the skeletal forms, catching the light and clearly defining the mechanical boundaries against the dark blue recesses of the movement. It is a meticulous choreography of surfaces where color and finishing technique are used to enhance legibility and three-dimensional perception.
Courtesy of Zenith
Visibility of the time is maintained through a peripheral flange that circles the outer edge of the movement area. This ring, finished in the same deep blue, anchors the gold-plated, faceted hour markers. Each marker is coated with Super-LumiNova SLN C1, ensuring that despite the complex, open background, the primary function of time-telling remains functional in low-light conditions. The hands are similarly crafted from solid gold to match the case, faceted for sharpness and coated with colored varnish and luminescence. Because there is no solid dial to obscure the view, the wearer can look past the hands and markers directly into the gear train, observing the interaction of wheels and pinions that drive the hours and minutes.
The barrel of the movement, located near the 12 o'clock position, is also skeletonized. This open barrel cover allows for a direct visual check of the mainspring's state of wind. As the watch is wound, the coils of the spring tighten, and as it runs, they expand, providing an analog, intuitive indication of the remaining energy. The movement provides a power reserve of 50 hours, a respectable figure for a high-frequency tourbillon which consumes energy at a faster rate than standard frequency movements. The automatic winding system ensures that the watch remains powered during daily wear, utilizing a solid gold oscillating weight that can be viewed through the sapphire crystal exhibition caseback. The rotor is finished with satin brushing, maintaining the industrial-luxe theme even on the reverse side of the watch.
The integration of the bracelet is a key feature of the Defy Skyline's identity. The solid rose gold bracelet flows directly from the case without the use of traditional lugs, creating a unified, seamless silhouette. The H-link design of the bracelet is engineered for comfort and light reflection, with each link featuring the same brushed and polished finishing as the case. The bracelet tapers slightly towards the solid rose gold double folding clasp, which provides a secure and balanced counterweight to the watch head. The sheer mass of the gold bracelet adds a tactile quality of value and substance, reinforcing the luxury proposition of the timepiece.
Courtesy of Zenith
For occasions requiring a less formal or lighter configuration, the watch utilizes Zenith’s quick-release strap system. This mechanism is built directly into the case structure, allowing the wearer to swap between the solid gold bracelet and the provided rubber strap without the use of tools. The rubber strap is color-matched to the intense blue of the movement and features a central pattern of four-pointed stars, echoing the motif found in the skeletonized mainplate. This strap option drastically changes the character of the watch, shifting it from a piece of jewelry-like opulence to a high-performance sport watch. The rubber strap is secured with its own solid gold folding clasp, ensuring that the premium material experience is maintained regardless of the strap choice.
The layout of the skeletonized caliber 3630SK is a study in transparency as structure. Unlike traditional skeletonization which often involves carving away material from an existing solid movement, the 3630SK appears designed from the ground up to be open. The Zenith star logo is not just a decorative element applied to the surface but is integrated into the bridge layout itself. The points of the star stretch across the movement, connecting the barrel, the gear train, and the escapement in a cohesive visual network. This structural transparency allows light to pass through the watch, creating shifting shadows and highlights that change with the angle of the wrist.
The crown, also rendered in rose gold, is screw-down, contributing to the watch's 100-meter water resistance rating. It is substantial in size, featuring deep knurling that makes it easy to grip and operate. The star emblem adorns the flat face of the crown, a subtle branding touch. When unscrewed, the crown allows for the winding of the mainspring and the setting of the time. The tactile feedback of the winding mechanism is crisp, a characteristic trait of the El Primero architecture. The robustness of the crown and its protective guards underscores the fact that despite its tourbillon complication, this is designed as a daily-wear sports watch rather than a delicate dress piece.
Courtesy of Zenith
Mechanically, the high-frequency nature of the El Primero movement is a significant technical differentiator. Most tourbillons on the market operate at 3 Hz or 4 Hz. By running at 5 Hz, the balance wheel oscillates ten times per second, offering potentially greater stability and precision recovery after shocks. This rapid oscillation is visible to the naked eye, giving the tourbillon cage a blurred, frantic appearance that conveys the mechanical power stored within the barrel. Zenith’s commitment to high-frequency chronometry is historical, and applying this performance standard to a tourbillon demonstrates a refusal to compromise on timekeeping performance for the sake of complications.
The choice of blue PVD for the movement finish is particularly effective when paired with the rose gold case. In color theory, blue and orange (or copper/gold tones) are complementary, sitting opposite each other on the color wheel. This creates a natural vibrancy where the cool, dark tones of the movement intensify the warm, glowing hues of the case metal. The rhodium plating on the bevels acts as a neutral bridge between these two extremes, preventing the contrast from becoming jarring. It is a modern colorway that feels technical and aggressive, suitable for a watch that is marketed under the banner of architectural precision and urban design.
The sapphire crystal protecting the face is flat with anti-reflective treatment on both sides. This is essential for a skeleton watch, as glare would obscure the depth and detail of the movement layers. The Zenith signature is printed on the underside of this crystal, floating above the mechanical landscape below. This "ghost" branding ensures that the logo is visible without cluttering the movement components or requiring a dedicated nameplate bridge. The rear sapphire crystal offers a view of the other side of the caliber, where the gear train and the backside of the tourbillon cage are visible, all framed by the massive rose gold caseback ring.
Courtesy of Zenith
The limited nature of this release, restricted to just 50 units, positions it as a rare collector's item within the broader Zenith catalog. It represents the top tier of the Skyline range, sitting above the standard three-hand and skeleton models. The exclusivity is driven not just by the production number but by the complexity of manufacturing the open-worked tourbillon movement and the extensive hand-finishing required to achieve the bi-color aesthetic on the bridges and plates.
The DEFY Skyline Tourbillon Skeleton Reference 18.9300.3630/78.I001 comes with a price tag of $103,700 USD (91,900 CHF / 102,800 EUR). This pricing reflects the use of a full solid gold case and bracelet, as well as the high-complication movement. It is available through Zenith physical boutiques, their online platform, and select authorized retailers globally. Given the extremely low production number of 50 pieces, availability is expected to be scarce, targeting a specific segment of collectors who value the intersection of high-frequency chronometry, integrated bracelet sports watch design, and open-worked architectural aesthetics.
Case: 41mm diameter, rose gold octagonal construction. Screwed-in crown. Water resistant to 10 ATM.
Movement: Automatic El Primero 3630 SK calibre, high-frequency 36,000 VpH (5 Hz). Skeleton tourbillon with bi-color finishes (blue PVD and rhodium-plated bevels). 50-hour power reserve. Solid gold oscillating weight with satined finishes. Functions include hours, minutes in the center, and a one-minute tourbillon at 6 o’clock.
Dial: Blue openworked design. Gold-plated, faceted hour markers coated with Super-LumiNova SLN C1. Solid gold, faceted hands coated with coloured varnish.
Strap: Solid rose gold bracelet with solid rose gold double folding clasp. Includes an additional blue rubber strap with a solid gold folding clasp. Features a full interchangeable strap system.
Price: $103,700 USD / 91’900 CHF / 102’800 EUR
Reference Number: 18.9300.3630/78.I001
Notes: This is the first tourbillon skeleton model in the DEFY Skyline collection. It is a limited edition of 50 pieces. The movement features an openworked architecture centered around the Zenith star motif.