It’s not often we see watch companies returning to the early- to mid-2000s era of watchmaking for inspiration. Although vintage reissues are a dime a dozen these days, watches typically don’t commemorate the early years of the 21st century, when enthusiasm for high-end mechanical watches was just beginning to expand beyond its ’90s status as a cultural niche.
Zenith was, like many brands at the time, growing. It had been acquired by LVMH in 1999, and in 2001 new leadership was installed in the form of CEO Thierry Nataf. The Nataf era at Zenith lasted until 2009 and – to put it nicely – it isn’t a period generally looked at favorably these days. The simplest way to describe it would be as a period of excess, and so I’ll leave it at that.

Zenith’s course was eventually corrected by Jean-Frédéric Dufour, who served as CEO at Zenith from 2009 to 2015, before becoming the chief executive for Rolex. Zenith is now led by Julien Tornare, who was installed by Swiss watch industry legend Jean-Claude Biver in 2017 and now has the brand on one of the watch industry’s hottest streaks. There is, however, one remnant of the Nataf era that remains at Zenith: the Zenith Chronomaster Open, a subdivision of the company’s flagship chronograph collection that was introduced by Nataf in 2003 and returned to the spotlight this year at Watches & Wonders Geneva 2022.
Nataf created the Zenith Chronomaster Open in order to highlight what made the El Primero special. By opening up the dial and exposing the escapement, he thought it would help a wider audience understand high-frequency watchmaking through the balance wheel’s 10 beats/vibrations per second. Nataf’s creation was a successful one that quickly found a wide global audience, and it’s remained in the Zenith catalog ever since.

“It’s a very strong concept that was created in 2003 in order to enable clients to understand high frequency [watchmaking],” says Romain Marietta, the Head of Product Development and Heritage Director at Zenith, whose tenure at the company dates to the Nataf era. “We had to rework the movement to skeletonize around the escapement position, to enable people to see inside the movement, to see the heartbeat – to help people understand high frequency.”
The Zenith Chronomaster Open has received a complete facelift this year, with a new movement, a new dial, and a new case measuring 39.5mm in diameter. An updated iteration of the caliber 3600 – first seen in last year’s Chronomaster Sport and Chronomaster Original models – is key here, with its fast-moving central seconds hand that makes one revolution around the dial every 10 seconds when the chronograph is engaged. The previous 42mm design that dates back to Dufour’s tenure at Zenith is now discontinued, and the new-for-2022 Chronomaster Open is available in three options (two in stainless steel, with either a silver or black dial; one in rose gold, with a silver dial) at launch. I’ll also note that this is the first time we’re seeing a no-date iteration of the caliber 3600.

While the addition of a caliber 3600 variant is the headline attraction here, it’s the new 39.5mm × 13.1mm case profile that should have the greatest impact when living with the watch. The case is similar in execution to the Chronomaster Sport, so much so that I even asked Marietta if it was identical to the Sport case, except with the ceramic bezel removed. (He says it’s slightly different, which makes sense given it’s about half a millimeter thinner.) I was chatting with someone recently who described the case of the new Chronomaster Open as somewhat similar to a pre-Daytona chronograph from Rolex, which I think is a fair comparison. The smooth, polished bezel, pump pushers with rounded tips, slim lugs, and notched push-pull crown all connote a certain toolish mentality.
The refreshed Chronomaster Open series also boasts the smallest lug-to-lug within the new Chronomaster family. It measures precisely at 45.2mm, compared to 46.2mm for the (thinner) Chronomaster Original and 47mm for the (thicker) Chronomaster Sport. That also makes it a bit smaller on the wrist than flagship alternatives from Rolex (46.6mm, for the Daytona 116500) and Omega (47.2mm, for the Speedmaster Professional 3861).

What makes or breaks the Zenith Chronomaster Open is whether or not you’re a fan of the “open heart” aesthetic on the dial. My understanding is that Zenith was the first to bring a watch to market with this style of exposed escapement, influencing countless other brands in the process. I personally struggle a bit with the concept, but I appreciate how Zenith has gone out of its way here to make the naturally asymmetrical dial layout a bit more aesthetically consistent than on previous generations.
The dial of the updated Chronomaster Open now consists of 16 total components. A hesalite window that consists of three overlapped circles highlights the balance wheel, the purple-blue silicon escape wheel (in the shape of Zenith’s signature star logo), and the seconds wheel. Similar to previous versions of the Chronomaster Open, the new caliber 3604 has received a subtle bit of skeletonization of the mainplate and movement bridges at the terminal end of the going train, in order to make the constant action of the escapement a touch more visible.

I also appreciate how we can actually see the extended pinion of the fourth wheel, which reaches up from the inside of the movement to the top of the dial to operate the running seconds sub-dial at nine o’clock. It’s not the most legible constant seconds display out there, but I think that’s forgivable given the amount of focus on the exposed escapement.
Where previous Chronomaster Open models decorated the movement bridges with perlage, Zenith has instead opted to finish the visible components with a three-dimensional, laser-engraved concentric azzurage pattern that better complements the decoration of the “non-openworked” sub-dials displaying the elapsed hours and minutes. It’s a thoughtful, subtle touch that will likely only be noticed by the most diligent of loupe-wearing owners.
That said, no matter how well-done all of these updates are, it’s likely they won’t change the opinion of those who find the exposed escapement design to be “down-market.” Zenith doesn’t, and shouldn’t, care. The Chronomaster Open has stuck around the past 19 years for a reason – it’s popular.

“It is one of the collections where we’ve had the most requests for special editions or executions locally in markets, specifically, it’s interesting to note, in Japan,” says Marietta. “We did, I think, 10 special editions of the Chronomaster Open over the last five or six years there.”

Even outside Japan, previous iterations of the Zenith Chronomaster Open were often used as the base for Zenith’s commercial collaborations, including memorable limited-edition watch releases with the Rolling Stones and – my personal favorite – Cohiba, the Cuban maker of fine cigars. It will be interesting to see whether or not Zenith continues to flex the Chronomaster Open as its primary vehicle for commercial relationships.
That said, I think it’s a bit too easy to dismiss the Zenith Chronomaster Open as a needlessly commercial product. The success of the line goes back to Nataf’s original remit for the Chronomaster Open, to open up the understanding of what makes the El Primero such a remarkable chronograph.

If you remember what makes the caliber 3600 so special, it’s that the chronograph mechanism is driven off a low-inertial escape wheel made of silicon – which is, of course, now visible through the dial – and it features a unique set of wheels with specialized gear teeth. It’s a solution that’s not dissimilar to the customized outfit of the original Clinergic 21 escapement used in Zenith’s 1969 El Primero, which increased the amount of teeth on the escape wheel to a total of 21 and empowered the very first examples of the inaugural high-beat self-winding integrated chronograph movement.

We shouldn’t discount the appeal the exposed escapement might hold for genuine fans of high-frequency watchmaking. After all, no matter who else mimics the “open heart” display (or who else brings a tenth-of-a-second chronograph to market), only Zenith can offer the intrigue and drama of a high-beat chronograph with an exposed escapement.

So if you want to experience Zenith’s latest innovation in an up close and personal manner, the Chronomaster Open might just be your best bet.