Zenith Chronomaster Sport Skeleton: El Primero 3600SK Goes Openworked — Four References for W&W 2026

Description

The Zenith Chronomaster Sport has always been a watch about its movement — the El Primero was the first high-frequency automatic chronograph when it launched in 1969, and the Chronomaster Sport line has been built specifically to show it off. At Watches & Wonders Geneva 2026, Zenith finally does the obvious and skeletonises both the dial and the subdials for the first time. Four references launch together: two in stainless steel, one in 18k rose gold with a black ceramic bezel, and one in 18k rose gold with 50 baguette-cut diamonds.

What makes this an event — rather than just a skeleton variant — is the engine. Zenith has introduced a new openworked evolution of the El Primero 3600, the El Primero 3600SK, keeping the chronograph's defining 5 Hz frequency and its 1/10th-second measurement directly on the bezel. The steel models also debut a new patented ceramic-ball micro-adjustable folding clasp — a serious everyday-wearability upgrade.

Design

The Chronomaster Sport case stays at 41mm, with the distinctive tricolour counters referencing the 1969 El Primero A386 still present — now rendered as skeletonised subdials floating over the openworked base. The two steel references are the collection's everyday heroes: one with a black ceramic bezel and the classic grey/anthracite/blue tricolour counters, and one with a green ceramic bezel and grey-toned counters. The rose gold reference pairs the openworked dial with a black ceramic bezel for a stealth-luxury reading, while the top-tier diamond model wraps the bezel in 50 baguette-cut diamonds and runs on a fully matching rose gold bracelet.

Specifications

Case diameter: 41mm (all four references)
Case materials:
- Stainless steel, black ceramic bezel
- Stainless steel, green ceramic bezel
- 18k rose gold, black ceramic bezel
- 18k rose gold with 50 baguette-cut diamond bezel and matching rose gold bracelet
Dial: Fully skeletonised, with skeletonised tricolour subdials (first time for the Chronomaster Sport line)
Bezel: Marked for 1/10th-second measurement (chronograph hand completes one full rotation every 10 seconds)
Crystal: Sapphire, AR-coated, sapphire caseback
Water resistance: 100m
Movement: Calibre El Primero 3600SK, in-house, automatic high-frequency chronograph (skeletonised)
Frequency: 36,000 vph (5 Hz)
Power reserve: 60 hours
1/10-second measurement via column-wheel chronograph with vertical clutch
Clasp (steel models): New patented folding clasp with on-wrist micro-adjustment in 2.5mm increments, 10mm total range, ceramic-ball locking system
Prices: EUR 16,500 (steel references); EUR 31,200 (rose gold with ceramic bezel); EUR 111,400 (rose gold with diamond bezel)

What's Exciting

For Freddy's value-for-money lens, this might be the most interesting Zenith launch of W&W 2026. At EUR 16,500 you get an in-house, skeletonised, 5 Hz high-frequency automatic chronograph that can actually measure to a tenth of a second on the bezel, in a 41mm steel case, with 100m water resistance and a brand-new ceramic-ball micro-adjust clasp that solves the "half-link problem" in sports watches. Very few of the obvious competitors at this price — Omega's Dark Side Speedmaster, Breitling's Chronomat skeleton variants, Tudor's Black Bay Chrono — offer in-house movements with this combination of frequency, measurement resolution and practical wearability.

The diamond-set rose gold version at EUR 111,400 is the top-of-line proof point: fully gold, fully skeletonised, still 5 Hz, still 1/10th on the bezel. If you want proof that Zenith intends the Chronomaster Sport to compete at the high-end as well, this is it.

History

The El Primero movement was introduced in January 1969 — effectively the same month as the Zenith-Movado El Primero launch and the Heuer/Breitling/Hamilton Calibre 11 announcement, in what became the great chronograph race of that year. The El Primero won on frequency: its 36,000 vph (5 Hz) allowed 1/10-second measurement through gear-train subdivision alone, whereas the competition operated at 4 Hz. The Chronomaster Sport line, reintroduced in 2021, was designed around the El Primero 3600 — a reworked family that finally let Zenith display 1/10-second subdivisions directly on the bezel. The skeleton references of W&W 2026 are the first time that architecture has been laid bare.