Under the hood is the in-house El Primero Calibre 3604, once again essentially the same movement as the Chronomaster Sport, only revised to have exposed parts. Being an Open Zenith, there’s of course a hole in the dial, which now takes quite some space between 9 and 12 o’clock, as it reveals the balance wheel, the escapement and the mechanism behind the small seconds, which sits under a transparent polymer plate. Sunray-brushed, with applied faceted markers and hands, it retains the classic grey and silver snailed sub-counters, emblematic of El Primero watches. New for this Zenith Chronomaster Open Boutique Edition is the dial, which adopts a deep blue colour – in the same vein as the Chronomaster Original Boutique Edition. It’s also a rather compact watch on the wrist, with an appreciable 45mm lug-to-lug measurement. It’s also a fairly resistant watch, with a 100m water-resistance and a duo of sapphire crystals on both sides of the watch. Crown and pushers are identical too, and the overall shape is that of a classic, modern watch with just a tad of vintage appeal.

The Chronomaster Open Boutique Edition, just like the standard models in this collection, is presented in a classic 39.5mm stainless steel case, which feels identical to the Chronomaster Sport in a shape and finish, yet has a slightly reduced diameter (minus 1.5mm), mostly due to the absence of the external ceramic bezel. And for this reason, it has far more appeal than the previous editions… Indeed, the Zenith Chronomaster Open is essentially a Chronomaster Sport without the ceramic bezel and with a hole in its dial. This new range of watches, which we discovered here in March as part of the Watches & Wonders novelties, is using most of the acclaimed Chronomaster Sport’s specifications, yet in a streamlined case, but with a more complex dial architecture. If the concept of the El Primero Open dates back to the 2000s, it has been revamped very recently with the new Chronomaster Open. And now, the Zenith Chronomaster Open is presented with a new dial colour, which is associated with the brand’s boutique editions. Something quite emblematic of the 2000s editions of this watch collection, it somehow lost a bit of its appeal… Until earlier this year, when Zenith brought back the concept with a far more modern take. The open-heart style has long been associated with the classic El Primero chronograph, with the fast-beating heart of the watch, its 5Hz escapement, fully exposed through a hole on the dial.

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