The Zenith El Primero is not a watch but in fact, a famous chronograph movement. Famous because Zenith was the first watchmaker to publically announce that it was working on an automatic chronograph (complete with a working prototype) in January 1969, which was groundbreaking during a time when only manual-wound chronographs were available. While it is still contested which watchmaker can lay claim to the first self-winding chronograph watch (Zenith was the first to announce, Seiko was the first to introduce models to the market but only in Japan, and the Breitling/Heuer/Hamilton consortium was the first to debut models to the international market), Zenith called its movement the “El Primero,” which is Spanish for “The First.” Five decades later, this revolutionary automatic fully integrated high-beat chronograph movement is still at the heart of the Zenith collection, albeit in evolved forms. Dig into our guide to popular Zenith El Primero models to see this legendary chronograph caliber in action.

In 2019, Zenith celebrated 50 years of the El Primero movement, so it came as no surprise that the company released a slew of commemorative models to mark the occasion. For instance, there’s the Zenith El Primero A386 Revival, which is a modern re-issue of the original model that started it all.

Like the vintage version, the modern Zenith El Primero A386 Revival features a 38mm case, a dial with tri-colored subdials, a domed crystal, mushroom pushers, and a 5 Hz (36,000 beats per hour) El Primero movement. However, Zenith made these anniversary models in three shades of gold—yellow, white, and rose—each limited to 50 examples only.

Another popular reissue is the Zenith El Primero A384 Revival, based upon a model that also came out in 1969, but sporting a distinct angular silhouette. From the 37mm faceted steel case to the lacquered white and black tachymeter dial, this modern version is yet again a faithful reissue of the original. There are modern touches though, such as sapphire crystal on both the dial-side and the caseback—which permits a view of the El Primero movement inside.

The Chronomaster is Zenith’s popular flagship chronograph collection, naturally all powered by El Primero movements. Characterized by round 42mm cases, three overlapping subdials, a date window at 6 o’clock, a tachymeter on the dial, and a pair of chronograph pushers flanking the winding crown, the Zenith Chronomaster El Primero is available in an assortment of materials including steel, rose gold, and two-tone steel and gold.

Another variation within the lineup is the Chronomaster El Primero Open, which includes a cutout on the dial to reveal the beating heart of the El Primero movement. There is also the Chronomaster El Primero Grande Date Full Open, which not only incorporates moon/sun phases and a large date window but also entirely skeletonized dials that put the legendary movement on full display.

In 2010, Zenith debuted the El Primero Striking 10th, a movement with a chronograph central hand that makes one revolution every 10 seconds (rather than the traditional 60 seconds)—thus permitting the measurement of 1/10th of a second.

The new Zenith El Primero Chronomaster 2, released in 2019, takes that Striking 10th concept but houses a new-gen El Primero movement named the Caliber 3600. The watches feature titanium 42mm cases topped with high-tech ceramic bezels, available in blue or black, with a tenth-of-a-second display on a scale with 100 graduations. The skeletonized dial allows a peek of the movement inside the watch while the red chronograph hand sweeps around the dial in ten seconds.

In 2017, Zenith introduced yet another major evolution of the El Primero movement for the 21st Century, this time encased in a new watch called the Defy. Incredibly, the Zenith Defy El Primero 21 has a chronograph hand that makes one revolution per second thanks to its 100th of a second chronograph movement.

In addition to the dizzying movement, stylistically the Defy is also cutting-edge. The watches come equipped with 44mm angular-shaped cases paired with round bezels, rectangular-shaped pushers, and skeletonized dials. What’s more, material choices include lightweight titanium, robust ceramic, sporty black carbon, and precious 18k rose gold. And for those looking for extra opulence, there’s even the option for diamond-paved cases.

From its inception in 1969 until today, the Zenith El Primero chronograph movement has earned its iconic status by continuously evolving with the times. Whether in a classic Chronomaster case, a vintage-inspired Revival model, or in the avant-garde Defy, the El Primero remains as the most popular Zenith chronograph driven by five decades of history.

Read more about the Zenith collection here.