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Profils El Primero (El Primero Original 1969, El Primero Striking 10th, El Primero Chronomaster Grande Date)

El Primero profiles (El Primero Original 1969, El Primero Striking 10th, El Primero Chronomaster Grande Date)

1969. Man walks on the moon; the Arpanet project – the ancestor of the Internet – is launched; Concorde takes off and defies the sound barrier; while hundreds of thousands of people flock to the Woodstock festival.


1969 marked another revolution, this time of the horological kind: the birth of the El Primero caliber, the first ever automatic chronograph. Better still, the caliber was integrated and designed as a complete whole with no additional module, but instead a column wheel and a central rotor on ball bearings.

El Primero, the first
automatic chronograph
in history

Another no less significant first was the fact that this movement beat at 36,000 vibrations per hour, making it the world’s most accurate chronograph.


This was an unprecedented feat, especially given the over 50-hour power reserve that was an exceptional performance for such a high-frequency movement. To complicate matters still further, the caliber was equipped with a date and miniaturized to a size of just 6.5 mm thick and 29.33 mm in diameter.

El Primero Chronomaster 1969

El Primero Chronomaster 1969


In 1970, an El Primero model crosses the Atlantic attached to the landing gear of a Boeing 707 on the AF015 Paris-New York flight

In 1970, an El Primero model crosses the Atlantic attached to the landing gear of a Boeing 707 on the AF015 Paris-New York flight


 El Primero Striking 10th, Calibre 4052

El Primero Striking 10th, Caliber 4052


While each of these criteria was revolutionary in itself for the time, together they represented a truly major accomplishment. Its technical specifications were indeed so complex that it took seven years to develop, and the legend has remained vibrantly alive ever since.


The El Primero is still the world’s most precise series-made caliber and the only one capable of measuring short times to the nearest 1/10th of a second.

The El Primero legend is still being written Such an exceptional caliber deserved to be exceptionally tested. In 1970, El Primero took the Air France AF015 flight from Paris to New York – but not comfortably installed on a traveller’s wrist. Instead, the El Primero crossed the Atlantic fixed to the landing gear of the Boeing 707.
The temperature stood at 4°C on the tarmac in Paris, whereas 20 minutes later, at an altitude of 10,000 meters, it had dropped to -62° and atmospheric pressure was four times lower.
After the landing in New York, during which it was subjected to terrible jolting, the watch showed it had remained accurate to the nearest second apart from the inevitable time-zone difference. El Primero had kept running at 36,000 vibraitons per hour and required no adjustment.

The El Primero caliber
continues to reign supreme
in the pantheon of watch precision

Despite this spectacular demonstration of its reliability, El Primero was temporarily upstaged by quartz and its production was suspended for nine years. Its big comeback in 1984 coincided with the rebirth of mechanical watchmaking, when prestigious brands were looking to Zenith and its legendary movement to equip its own watches.


Over 40 years later, El Primero remains firmly enthroned in the precision hall of fame and continues to equip Zenith timepieces. Over the decades, it has constantly evolved and been enriched with complications and avant-garde mechanisms rewarded by countless prizes. Its various interpretations, laying down new milestones in the history of time measurement, are now regrouped within a complete collection bearing its name. Year after year, El Primero continues writing its legend in order to forever remain “The First”.

  • Charles Vermot

    Charles Vermot

    An everyday hero

    Having safeguarded the El Primero production equipment, Charles Vermot enabled Zenith to begin producing its legendary chronograph again in 1984.

    More information
  • Academy Christophe Colomb

    Academy Christophe Colomb

    The "gravity control" module

    Resulting from five years of intense development, this complication represents one of the major breakthroughs in 21st-century watchmaking.

    More information

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