Zenith Chronomaster Sports Review: An Amazing Chronograph Accurate to 1/10 of a Second

This is a hands-on review of the Zenith Chronomaster Sport. This chronograph watch is equipped with the El Primero 3600 movement. Its exterior incorporates elements of classic timepieces and features a chronograph function capable of measuring time accurately to 1/10 of a second. This chronograph will teach you the joy of measuring time.

The successor to the legendary chronograph

　This time, we'll be reviewing the Zenith Chronomaster Sport, a chronograph watch released in 2021. While incorporating details that pay homage to classic models of the past, the watch is equipped with the Caliber El Primero 3600, released in 2019, and is a watch that embodies the Zenith worldview both inside and out.

　The original El Primero, born in 1969, is one of the earliest automatic chronograph movements. It combines a classic horizontal clutch with a carrying arm and a compact reverser-type automatic winding mechanism to create an automatic chronograph. Another distinctive feature is its high beat rate of 10 vibrations per second. In addition to its theoretically superior portability, it also offers the advantage of being able to measure more precisely as a chronograph.

　Even more surprising is that, despite being a movement from the early days of automatic chronographs, it has remained a long-selling product, continuing to be produced without any major changes to its basic design. Behind this lies the story of Charles Vermot, one of the developers. In 75, he disobeyed orders from the company's management and hid the technical manuals and production equipment in his attic, but after 10 years, they were finally allowed to see the light of day again.

　Born after a fierce development race, it endured the quartz revolution, and was updated to mark the 50th anniversary of the Caliber El Primero 3600. The fact that it is such a lifelike movement is probably what attracts so many enthusiasts.

Tricolor color that pays homage to the first model

　Let's start with the dial. The refreshing white lacquered dial features three subdials. The 60-second counter is at 3 o'clock, the 60-minute counter at 6 o'clock, and the small seconds at 9 o'clock, each color-coded blue, dark gray, and light gray. This tricolor color pays homage to the first model equipped with the El Primero, the A386. Perhaps because it is based on the expansive color white, or perhaps because the contrast between the three colors is kept to a minimum, the impression is not overly flashy or lively.

　The date display is located at 4:1. It doesn't overlap with the sub-dials or minute markers, obscuring the scale, a testament to the precision of this chronograph. The window is recessed, but the date disc itself is recessed, making it appear slightly dark.

　The hour and minute hands are baton-shaped. Because they are slender, even when they overlap with the counter, the impact on reading the measured time is kept to a minimum. Although they are thin, visibility is ensured by the polished finish, black paint, and white Super-LumiNova.

　The indexes are trapezoidal cut and shine when exposed to light. The top surface is painted black, while the surface facing the center of the dial is coated with Super-LumiNova, enhancing the sense of unity with the hour and minute hands and enhancing visibility.

　The three chronograph hands have red tips to avoid confusion with the time display hands.

　The bezel surrounding the dial is made of scratch-resistant ceramic and is marked in 1/10th-second increments. The wide black bezel emphasizes the sporty nature of this watch.

Powerful case lines and a delicate pump-type pusher

　The stainless steel case is 41mm in diameter. While the brand's official website does not specify the length or thickness, actual measurements indicate that it is 46.5mm and 13.5mm, respectively. These are roughly within the standard range for an automatic chronograph watch.

　The design strikes a perfect balance between boldness and delicacy. The middle case flows into the lugs while maintaining its volume, dropping off cleanly as if it were cut off. This creates multiple edges at the lug tips, giving the watch a powerful look. The edges themselves are moderately rounded, so they generally don't hurt your fingers when you touch them. There are still sharp edges on the inside of the lugs, but since they're not usually in contact with the skin, you probably won't notice them unless you switch to an extremely thin strap. The tops of the lugs are finished with a fine satin finish, while the other surfaces are polished.

　The pump-type pushers are a testament to the watch's delicacy. They create a classic impression while maintaining sharp proportions. If the pushers were more ostentatious, screw-in style, the image of this watch would have been quite different.

　The crown, with its star-shaped relief on top, is relatively large in diameter. Because it is not screwed down, it can be left in its original position for manual winding, pulled out one notch for quick date setting, and pulled out two notches for time adjustment. Although the crown itself is low, it is easy to grip because the bezel does not protrude and the case back is partially recessed.

　The strap, officially described as "blue Cordura effect," has a texture that resembles a rubber surface combined with fabric. It's likely water-resistant, too. It's stitched, and looks like a completely fabric strap.

　The buckle is a double-opening folding type. One side of the buckle is held in place nicely by a ceramic ball, while the other side opens with a push button. The push button feels a bit catchy and not very smooth to operate, but I think my impression will change once I get used to it, or once it wears down with use. Although it is a folding buckle, it is equipped with a push rod, so when closed it looks almost like a pin buckle.

　The case back is secured to the middle case with four screws and is see-through, allowing you to fully appreciate the movement inside.

Caliber El Primero 3600

　Let's take a quick look at the Caliber El Primero 3600 that powers this watch. This movement is a descendant of the El Primero (Caliber 3019PHC) that was introduced in 1969, and is a 10 vph automatic chronograph movement. However, there are two major functional differences between it and the original.

　First, it is now possible to accurately measure to 1/10 of a second when the chronograph is running. Conventional chronographs, including previous El Primero models, have a central chronograph seconds hand that rotates once every 60 seconds. To measure sub-second intervals, this requires reading extremely precise markings. However, the El Primero 3600 has a central chronograph hand that rotates once every 10 seconds, making it easy to read to 1/10 of a second.

　The chronograph mechanism is basically powered by the wheel train that displays the time. In a typical chronograph, the fourth wheel that moves the second hand is connected to the chronograph wheel train by a clutch, transmitting power. However, in the El Primero 3600, power is transmitted from the escape wheel, which rotates faster than the fourth wheel, via an intermediate wheel, allowing the chronograph hand to move in finer increments.

　However, in exchange, the El Primero 3600 must use one of the subdials as a 60-second counter, and can only measure up to 60 minutes.

　Another difference is the use of silicon parts. By using silicon for the escape wheel and pallet, magnetic resistance is improved and the power reserve is extended to approximately 60 hours. This successfully gives the classic El Primero modern specifications.

An elegant chronograph that adds a touch of freshness to your wrist

　As you'd expect from a flagship watch from a long-established brand, it feels effortless to wear and fits comfortably on the wrist like a familiar watch. As an automatic chronograph, it is thick and heavy, but the curved lugs that fit snugly to the wrist and the thick rubber strap provide firm support for the case.

　Visibility is also excellent. The hour and minute hands are perfectly aligned to their designated positions, and all 12 indexes are coated with Super-LumiNova. The small seconds hand is a little difficult to read because it is a light gray with white markings, but the center of the hand is painted black, so it is easy to read the approximate number of seconds.

　This may vary from one watch to another, but I was a bit bothered by the free-hanging strap. When wearing the watch, the looped stitching of the free-hanging strap rests against the inside of the wrist, and the stitching thread constantly irritates the wrist, making it uncomfortable. Pressing a heated metal against the strap would melt the thread and make it less of a nuisance, but since it's not my own watch, I obviously can't do that. I can't say for sure about Zenith, but most straps are produced by external suppliers. This makes thorough quality control difficult, but since it directly affects the wearer's comfort, I'd like to see strict control over this.

　Let's start the chronograph. The pusher at 2 o'clock controls the start and stop functions, while the pusher at 4 o'clock controls the reset function. The pusher heads are rounded and fit comfortably in the fingers. After a little play, the measurement starts with a light touch. The chronograph hand, which makes one rotation every 10 seconds, is simply breathtaking. The stop and reset functions are similarly light. Sports watches equipped with chronograph mechanisms often have stiff pushers to prevent malfunctions. In this case, the pushers are probably set to a light feel, likely due to the emphasis on precise measurement. Even if it can measure to 1/10 of a second, if you use a stiff pusher, there will be a time lag before the user's intention is transmitted to the machine.

　Turning to the case back, a watch lover's dream unfolds. It's brimming with the unique features of a mechanical chronograph, such as the blue column wheel and the carrying arm with two intermediate wheels. Looking at the watch with one hand, or with your fingers on the pushers, is sure to be a blissful experience. It would be even better if the reset hammer was more visible, but considering that it's an automatic winding mechanism, we can't be picky.

"Practical" high-frequency chronograph function

　Many watch functions are so over-specced that it's difficult to appreciate their benefits. Diver's watches with ultra-high water resistance for saturation diving and pilot's watches with low-pressure resistance capable of keeping up with the acrobatic maneuvers of fighter jets are merely romantic features for the average person. Chronographs that boast a 10 vibrations per second and the ability to measure time to 1/10 of a second are similar.

　The great thing about the El Primero 3600 is that it doesn't just leave this function as a romantic idea, but is actually practical. There's a difference between what's theoretically possible and what's practically possible. It would be embarrassing to have to stare at the minute markings, nod along, and finally read out the measured time. However, with this model, you can see the measurement results down to 1/10 of a second in a completely natural way. With the Chronomaster Sport on your wrist, you'll be able to see the world below the decimal point, a world that's been difficult to focus on until now.