Zenith, as most of you are probably aware, introduced the El Primero chronograph caliber way back in 1969. It was notable for, among other aspects, its uncommonly high frequency of 36,600 vph (5 Hz), which in practical terms meant that its chronograph could record elapsed times not just to the second but to the 1/10th second. In most watches that housed the movement, however, the dial was not designed to actually record these minuscule measurements in an easily legible way. For the new Chronomaster Sport, unveiled last week, Zenith remedied this, adding an ultra-readable ceramic bezel with an etched, graduated 1/10th-second display.

Ref. 03.3100.3600/69.M3100 on steel bracelet

The Chronomaster Sport marks, according to Zenith, “a new era for the quintessential Zenith sporty-chic chronograph,” the El Primero-equipped Chronomaster, whose more recent variations have included more retro-influenced models like the Chronomaster A385 Revival. The new model bears some of these vintage influences: its sleek, 41-mm steel case features the pump-style chronograph pushers of earlier models, and the tricompax dial (in either matte black or matte white) hosts a set of overlapping subdials in the classic El Primero colors of blue, anthracite, and light gray, just as they appeared on the classic A386 model from 1969.

Ref. 03.3100.3600/69.M3100 on cordura-effect rubber strap

Definitively modern in contrast to these details is the polished black ceramic bezel, with its white-etched scale for recording 1/10-second timing intervals, which debuts on this new watch and imparts a substantial portion of its “Sport” character. The most recent evolution of the El Primero caliber, it powers a central chronograph seconds hand that makes a complete rotation around the dial in 10 seconds rather than 60, enabling the wearer to read elapsed times to 1/10th second directly on the bezel. The movement, on display behind a sapphire caseback, is constructed to visually highlight the enlarged blue column wheel and lever-operated lateral clutch as well as the openworked rotor with Zenith star motif. It is equipped with a stop-seconds function, and stores 60 hours of power reserve — 10 hours more than the standard El Primero Caliber 400. Among the many enhancements that Zenith’s engineers applied to this version of the caliber is an improved teeth design for the wheels, which makes for more precise timing.

Ref. 03.3100.3600/21.M3100 on steel bracelet

Ref. 03.3100.3600/21.M3100 on cordura-effect rubber strapZenith fans and collectors may recall the “prototype” version of the Chronomaster Sport, which debuted as a limited edition in 2019, one of three that comprised a “past-present-future” set released in early 2019 for El Primero’s 50th anniversary year. This new collection represents a visual and technical streamlining of that piece, with a more prominent ceramic bezel and a slimmed down case size, from 42 mm to 41 mm. The date display, which migrated to 6 o’clock on the limited edition, has returned to its traditional 4:30 spot on the Chronomaster Sport.

The El Primero caliber is visible through the caseback.

Both models are available on a new integrated steel bracelet, built to resemble the Gay Frères bracelets found on Zenith models of the 1960s; and on a textured cordura-effect rubber strap. The watch is priced at $10,000 on the bracelet and $9,500 on the strap.