Zenith has always been all about pushing the boundaries of mechanical timekeeping precision. The Le Locle-based manufacture still holds the world record for chronometry Observatory Prizes, at 1,565. In 1969, Zenith made history with the introduction of the original El Primero caliber, which was notable for, among other aspects, its uncommonly high frequency of 36,600 vph (5 Hz), which in practical terms meant that its integrated chronograph could record elapsed times not just to the second but to the 1/10th second. The El Primero would become the cornerstone upon which Zenith would build its modern brand for many years to come. In most watches that housed this now-famous movement, however, the dial was not designed to actually record these minuscule measurements in an easily legible way. This year, Zenith remedied that with the introduction of the Chronomaster Sport series, which houses the most recent, most optimized version of the El Primero and introduces an ultra-readable ceramic bezel with an etched, graduated 1/10th-second display.

The Chronomaster Sport marks, according to Zenith, a new era for the quintessential Zenith sporty-chic chronograph,” the El Primero-equipped Chronomaster, whose other recent variations have included more retro-influenced models like the Chronomaster Revival Manufacture Edition and Chronomaster A385 Revival. The new model bears some of those models 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, as on our review model, 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. The case boasts an appealing array of satin-brushed and mirror-polished finishes on its curves and facets, all the more prominent on the bracelet-mounted version of the watch I reviewed, where that variety of shiny and matte surfaces continues seamlessly from lugs to links.