A skeletonised take on one of watchmaking’s most important chronographs brings the mechanics of 1/10th-second precision fully into view
There is a certain confidence required to skeletonise a chronograph. Done poorly, it becomes visual clutter masquerading as complexity. Done well, it reveals the logic and beauty of mechanical watchmaking without sacrificing legibility or purpose. The new Zenith Chronomaster Sport Skeleton largely succeeds because it understands the difference.
At its core remains the El Primero 3600, the latest evolution of one of modern horology’s foundational movements. Operating at 5Hz—or 36,000 vibrations per hour—the calibre allows the central chronograph hand to complete a full revolution every 10 seconds, enabling a true mechanical 1/10th-of-a-second display against the ceramic bezel. In an industry where “high frequency” is often treated as marketing shorthand, Zenith remains one of the few brands genuinely built around the concept.
The skeletonisation itself feels restrained in the best possible way. Rather than aggressively hollowing out the movement, Zenith has preserved enough structure to maintain visual coherence and, crucially, chronometric stability. Through the smoked sapphire dial, the column wheel, horizontal clutch and star-shaped rotor become part of the watch’s visual identity rather than technical Easter eggs reserved for the caseback.
Importantly, the Chronomaster Sport does not lose its everyday usability in the process. The familiar tri-colour overlapping counters remain intact, preserving a direct line back to the original 1969 El Primero, while the faceted hands and Super-LumiNova-treated markers keep things surprisingly readable despite the openworked architecture. This still feels like a sports chronograph first, not an exhibition piece disguised as one.
The bigger surprise may actually be the bracelet. Alongside the new watch, Zenith introduces its Zenclasp folding clasp, a 41-component system developed over three years with on-the-fly micro-adjustment and ceramic ball-based locking components designed for long-term durability.
Available in steel with black or green ceramic bezels, alongside rose-gold variants, the Chronomaster Sport Skeleton brings the El Primero’s high-frequency architecture into sharper focus, transforming one of watchmaking’s most influential chronograph calibres into a visible part of the experience.
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