The History of Zenith Chronograph Wristwatches: Zenith Chronomaster with El Primero

Swiss Made Watches: The Story of Zenith El Primero

Developing an automatic chronograph was a huge challenge.

This is evident from the fact that 40 years passed between the time when the automatic winding mechanism was first developed and when it was actually implemented in a chronograph.

Finally, in 1969, the world's first custom-designed automatic chronograph movement was born: El Primero.

Founded in 1865 by Georges Favre-Jacot, Zenith has always been ahead of its time.
It can be said that this is a great achievement that is the result of embarking on mass production using machines.

This feat was a historic one in the history of watches.

In fact, at the same time that Zenith developed its custom-designed automatic chronograph, a similar automatic chronograph was also developed.

It was completed by a group including Breitling and Heuer-Leonidas.

However, the automatic chronograph that your group developed was a two-stage modular micro-rotor type.

However, El Primero had a chronograph mechanism embedded in the main plate from the beginning, and was automatically wound by a central rotor, making it a truly chronograph-only watch.

Thus, the El Primero movement came to be known as the world's first custom-designed automatic chronograph.

Now, El Primero means number one in Spanish.

And as its name suggests, El Primero was praised worldwide as a masterpiece movement that brought together Zenith's knowledge and wisdom.

Zenith created the masterpiece El Primero, which took seven long years to complete, but it was soon unable to compete with the wave of quartz.

Finally, in 1972, Zenith came under American ownership.

This also meant the end of production of the El Primero.

However, there was one person who firmly believed that mechanical watches would make a comeback.

That person is Zenith's chief manufacturer, Charles Vermot.

He secretly hid the molds and blueprints for the El Primero in the attic of his factory.

Thanks to Charles Vermot, El Primero was able to breathe new life into itself again in the 1980s.

He can be said to be the unsung hero behind the revival of El Primero.

By this time, the American management had already left, and El Primero was revived by Swiss management.

Subsequently, in 1997, in addition to Cal. 400 and Cal. 410, the Cal. 405, which was equipped with a flyback function, was released.

Thus, to this day, El Primero remains one of the world's best automatic chronograph movements.

The standard model of El Primero

The Zenith Chronomaster is a model that inherits the essence of El Primero's "3019PHC."

Zenith introduced this watch in 1969.

It was the world's first engineered self-winding chronograph movement.

There is a 30-minute counter at the 3 o'clock position.

There is also a 12-hour counter at 6 o'clock and a small second at 9 o'clock.

The calendar display is also between 4 and 5 o'clock.

This watch is equipped with Cal. 400, which is the basic style of El Primero, and is part of Zenith's elegant line, named after the Master of Time.

Current El Primero Movement

There are currently four variations of the El Primero movement.

The first is Cal. 400, the simplest movement with a date.

The second is Cal. 405, which adds a flyback function to Cal. 400.

The third is Cal. 410, which is equipped with a triple calendar and moon phase.

The fourth is the hand-wound movement Cal. 420, which is used in pocket watches.

All of these are based on the Cal.400.

It is the successor to the world's first automatic chronograph movement, which appeared in 1969 under the caliber name "3019PHC."

Class El Primero

Cal. 400 is installed in the classic-looking "Class El Primero" and "Chronomaster El Primero."

This movement, Cal. 400, is the base caliber for El Primero.

All other calibers are derived from this Cal.400.

The Cai.400 has a diameter of 30mm and a thickness of 6.5mm.

In addition, there is a 30-minute counter at the 3 o'clock position and a 12-hour counter at the 6 o'clock position.

There is a small second hand at the 9 o'clock position and it also has a calendar function.

The specs are an astounding 36,000 vibrations per hour.

Cal.405 with flyback function

Cal.405 is a movement that has 12 different parts from Cal.400 and also features a flyback function.

When timing, if you press the start button and then immediately press the reset button, the chronograph hands will return to the zero position and start timing again.

Cal.410 with triple calendar

Cal.410 is the basic movement Cal.400 with the addition of a calendar function.

This is featured in the Chronomaster El Primero.

The diameter and other dimensions of this watch are the same as those of Cal. 400 and remain unchanged.

However, in addition to the date display, the month and day of the week are displayed at the top of the dial, and the moon phase is displayed at the 6 o'clock position.

Manual winding chronograph Cal.420

This manual winding chronograph is a movement that has had the automatic winding function removed from Cal.400.

Currently, it is only found on pocket watches.

On top of the dial are a tachymeter and a telemeter.

One of the features of this model is that the crown is located at the 12 o'clock position, so the sub-dial display is different from other models.

Previous El Primero models

El Primero was born in 1969 and was the world's first dedicated automatic chronograph movement.

Throughout history, production was at times halted due to the popularity of quartz.

However, in 1980, production of the El Primero began again.

It's been about 30 years since then.

There will not be any major changes for the sake of cost reduction, but rather it will evolve little by little.

What models have been available so far that feature the El Primero?

Here, I would like to briefly trace the history of models equipped with the Eli Primero movement.

Reference G381

The Ref. G381 was produced between 1969 and 1972.

This model is extremely rare, with only 700 produced in 1969, the year the El Primero was released.

This model was produced for only a few years after the first El Primero was manufactured.

The dial has two different colors: a white base with black subdials.

And it has a tachymeter.

Reference 01.200.415

This model was manufactured in the 1970s.

It has a futuristic feel to it, typical of designs from that time.

4,950 units were produced.

The blue used on the dial is also something that is no longer seen today.

The case, subdials, and push buttons are all square, making for a very bold design, and it still looks fresh even today.

Reference A787

This is an early 1970's model.

The integrated lug and case design is very fresh and sophisticated.

The colors are uniformly silver and white, giving it a simple look.

Among them, the chronograph hand with a red square at the tip is an accent.

The number produced is 1,500.

Reference 01.0240.410

It wasn't until the 1980s that production of the El Primero resumed.

When production restarted in 1986, Zenith first featured this in their in-house model, which is still on sale to this day.

This model is equipped with a triple calendar and moon phase.

Furthermore, it is a higher-end model than the El Primero, which uses Cal. 410.

Reference 01.0180.415

This model was produced between 1972 and 1975.

This aviator model is equipped with a rotating dial with 12-hour display and a tachymeter to measure flight times.

Only 100 were produced, making this a very rare model.

The combination of the black dial, bezel and blue chronograph hands gives off a very bold and stylish impression.

Reference 375

The year 1990 marked the 120th anniversary of Zenith's founding.

This commemorative model was released in a limited edition of only 500 units worldwide to celebrate this milestone, making it an extremely rare and valuable model.

The luxurious 18K yellow gold case and white dial are impressive.

The serial number is also engraved on the dial at 8 o'clock.