Surprise was what the Zenith El Primero Stratos Flyback Striking 10th chronograph elicited when it was first shown at BaselWorld in 2010. The mesmerizing effect of the large red hand moving faster than expected was, without doubt, what most watch lovers would define as their “Striking 10th moment”, when previous expectations on how a chronograph should behave were demolished at the push of a button.
Indeed, this was a watch whose significance had to be demonstrated before it could be understood. No doubt, an explanation of the innovation that it contained could have been given beforehand, but imagine yourself in the shoes of jaded watch journalists attending the launch, who, on seeing the familiar tri-compax layout on the dial, would have expected yet another run-of-the-mill chronograph. If you have no idea what I’m talking about, then a trip to your nearest Zenith dealer is in order to see this watch in action. On activation of the chronograph pusher, the large red chronograph hand at the center starts moving at a decidedly faster pace, completing one revolution of the dial in 10 seconds, instead of the usual — and now rather pedestrian — 60 seconds.
Aside from the visual sensation of speed given by the quicker completion of the chronograph seconds hand’s journey around the dial, what is less obvious — unless one looks closer and pays heed to the name of the movement — is its ability to measure to a 10th of a second. A quick calculation of the Zenith-mandated 36,000vph that the El Primero is capable of makes one realize that 1/10th of a second is the smallest unit of time possible that can be measured, being that this is equal to one beat of the movement.
Over 40 years have passed since the legendary El Primero was first launched in 1969, and it was with the mere addition of 11 new components that this astounding performance was made possible. Visible through the sapphire caseback is one of these components: a double-layered clutch wheel composed of silicon and cut with 100 teeth that correspond to the 100 beats that are made per revolution, every 10 seconds. The net effect of these 11 new parts was the creation of the ultimate El Primero movement, with its famous frequency of 36,000vph fully expressing the limit of its measuring capabilities.
Enter the Zenith El Primero Lightweight, a technically tricked-out version of your basic Striking 10th chronograph, which is, simply put, the best expression of Zenith’s technical capabilities in one watch. What we have here is a watch that weighs a mere 40g in total; its astonishing lightness is achieved by replacing standard materials with exotic alternatives like carbon, aluminum, titanium and silicon. The heaviest parts of the movement — namely the mainplate and bridges — are made of titanium, with the lever and escape wheel now rendered in silicon, just like the double-layered clutch wheel. 
Externally, we find that the 45mm-diameter case is now made of carbon, with an attractive chequered-weave effect, while the inner structure is composed of a light but sturdy “ceramized aluminum”. Even the dial is semi-skeletonized, in keeping with the weight-saving philosophy of the watch, as well as to allow a view into the workings of the movement. In fact, even though Zenith is more associated with aviation than motorsport, one cannot help but make the comparison between this watch and a Formula 1 car, given the similarity in extreme lightness and performance. It would certainly look at home on an F1 driver’s wrist; and on the strength of this watch alone, perhaps its appearance would open the door to Zenith’s involvement in motorsport in the future. This isn’t that farfetched an idea, given that an earlier El Primero movement was used in the first version of the motorsport-focused Rolex Daytona.
Zenith has pulled out all the stops here, and as a technical showcase, the El Primero Lightweight is a droolworthy piece that packs in so much that it will be highly sought after — and all the more so since it is only available as a 250-piece limited edition. For the El Primero fan who is looking for a little more of an avant-garde edge, this watch will certainly tick all the boxes.
