The Zenith El Primero – Revisiting One of The Most Iconic Movements Ever

By rolex
June 6, 2021
8 min read

Icons stand the trial of time. Brought into the world in 1969, El Primero (the first in Spanish) is as yet viewed as truly outstanding and most exact chronograph developments at any point made. Part of a set of three of programmed chronograph types that hit the market in 1969, it is the one in particular that is as yet delivered to date. As Zenith gets ready to celebrate the 50th anniversary of this incredible type one year from now, MONOCHROME investigates its history and design.

The origins

Chronograph wristwatches have existed since the beginning of the 20th century (around 1912 or 1913 for the most punctual models) yet every one of them were fitted with hand-wound developments. In the 1960s, it was the ideal opportunity for the chronograph to modernize itself, by adding the reasonableness and comfort of programmed winding. Watchmakers set out on a genuine competition to develop the main self-winding chronograph. Three gatherings began to develop their own undertaking, each with their own benefits and their own specialized vision.

  • The Chronomatic was the undertaking of a consortium uniting Heuer, Breitling, Hamilton-Buren and chronograph expert Dubois-Depraz. It considered the Caliber 11, a measured development dependent on a miniature rotor Buren development and a Dubois-Depraz chronograph mechanism.
  • The Seiko 6139 calibre was a 27mm integrated section wheel chronograph with vertical coupling and beating at 21,600 vibrations/hour (or 3Hz).
  • The Zenith – code-named 3019 PHC calibre – was a high-recurrence integrated chronograph with a flat grasp. Better known as El Primero, this development was initiated in 1962 with the objective of presenting the development in 1965 to coincide with the centennial of the brand. The type was additionally named ‘Datron HS 36’ at Movado, which commercialized the development under the Zenith-Movado-Mondia consortium.

The Zenith programmed chronograph was the first to be disclosed to the world. It was introduced in January 1969 in a question and answer session and suitably dedicated El Primero (first in Spanish). The fact of the matter is a smidgen more complex. There are numerous discussions about which was the principal programmed chronograph, as both the Seiko and the Chronomatic developments were reported later the exact year. What’s more, El Primero was not the first to hit the market. The discussion about who started things out doesn’t truly matter any longer … yet what is significant is the indisputable actuality that there are not very many developments, specifically, chronograph developments, that can all the while celebrate a large portion of a centennial and continue to be delivered to control watches. This basic truth remains as proof of El Primero’s significance and enduring design.

Saved by a demonstration of rebellion – Charles Vermot

In the 1970s, the post-war worldwide financial expansion reached a conclusion. The new, precise quartz watches gained ubiquity and plunged the Swiss watch industry in a profound emergency. Zenith was offered to an American company called the Zenith Radio Corporation. Aiming to advertise quartz watches exclusively, the Chicago-based company chose to stop the creation of every mechanical development, included that of the El Primero calibre.

The news was welcomed with extraordinary consternation by Charles Vermot, who had gone through years working with Zenith and had followed the development of El Primero since the time the principal outlines became animated. Ignoring orders, Vermot covertly shrouded all the gear and tooling fundamental for the creation of the chronograph the brand had invested such a lot of time and cash in developing.

During the 1980s, Zenith had the option to continue the creation of El Primero without having to redevelop tooling, first for Ebel – which would utilize El Primero for a portion of its models. This was instrumental in the choice taken by Rolex to supplant the hand-wound Valjoux 72 powering its Daytona with a programmed chronograph development. The Rolex type 4030, an El Primero with an adjusted controller ticking at 28,800 vibrations/hour, a Breguet hairspring, an altered segment wheel and a customized rotor, would control the famous chronograph for more than 10 years until the dispatch of the Rolex in-house type 4130 in 2000. Aside from Rolex, numerous brands have furnished their watches with this development. The rundown includes names like Daniel Roth, Bvlgari, Panerai, Hublot or TAG Heuer…

El Primero under the loupe

Beyond its authentic significance, the life span of El Primero justifies itself with real evidence. This programmed chronograph includes a compact and comprehensive development and – considering its relatively little size and the high recurrence of its oscillator – flaunts a streamlined force save. Obviously, it has end up being reliable. It includes a 3-6-9 design providing a decent look.

High Frequency

High-beat wristwatches are quite uncommon, particularly back in 1969. Girard-Perregaux was advertising the sequential creation of high-beat wristwatches during the 1960s as a significant accomplishment, an accomplishment that justified outstanding outcomes at the Neuchatel Observatory preliminaries. Girard-Perregaux and the Fabriques d’Assortiments Réunis (F.A.R.) research facility were granted the Centenary Prize of the Neuchatel Observatory in 1966. F.A.R was likewise being entrusted with the development of the El Primero high-recurrence regulator.

In a nutshell, high-recurrence developments should be more exact (in principle, as there are numerous components influencing the exactness of a development). Operating at 36,000 vibrations/hours, the seconds hand of El Primero performs 10 bounces each second – meaning that it can quantify a 10th of a second. Finally, the seconds hand of the chronograph clears easily and is a proof of the heavenly engine inside the case.

Column wheel

El Primero is a segment wheel activated chronograph, opting for the most conventional and honorable framework to command the beginning, pause and reset elements of the chronograph. Cam activated chronographs are likewise hearty and reliable, yet this less complex practical arrangement does not have the appeal of the section wheel. Additionally, the beginning of the chronograph is more precise and the feeling when pressing the pushers is far smoother with a section wheel movement.

Horizontal clutch

The coupling between the chronograph and time-keeping gear train is performed by a level grip. The level grasp is, without an uncertainty, the most outwardly appealing arrangement. The stuff, which is allowed to rotate left and right (evenly), permits the association of the stuff train to the chronograph’s focus wheel. However, the cutting edge vertical grasp is frequently viewed as an actually more effective arrangement. The coupling is made vertically by erosion and dissimilar to even grasps, there are no teeth to draw in or separate (which may cause the hop of the chronograph seconds hand when the teeth lattice and wear after some time). In any case, the flat grasp makes for a lot more pleasant development, with most parts being obvious when looking through the sapphire caseback.

Reset mechanism

Two hammers are utilized to respectively reset the seconds and minute heart-formed cams and the hour heart-molded cam. The reset instrument incorporates a reset hammer jumper allowing for a smooth, complete capacity resetting.


In its 50-year history, El Primero has advanced in numerous ways. The re-industrialisation of the development in 1987 (reference 400) was the event to introduce a few upgrades. Yet, the development has additionally been refreshed in the casing of continuous advancement, specifically, by incorporating current advances to advance in synchrony with the occasions. The watch industry has gone through broad industrialisation and modernisation. For instance, modernized pinion wheels and springs, ceramic metal balls or all the more as of late LIGA-delivered heart-formed cams (allowing for significantly more effectiveness than stepped parts) are utilized inside El Primero. A silicon escapement (with banking integrated into the anchor) has been introduced starting at 2014 and is widely utilized on the open-heart versions.

And normally, El Primero has been redesigned with various extra capacities and highlights: schedules, tourbillon, moon stages, fly-back, power save indicators, extra time regions or the amazing El Primero Striking whose focal seconds hands makes a complete revolution in 10 seconds, every one of its means precisely indicating a 1/10th of a second against the 100 graduations on the dial.

Since 1969, more than 70 forms of El Primero have been referred to by Zenith: 3019 PHC, 3019 PHF, 400, 400 Z, 410, 410 Z, 405, 405 Z, 420, 420 Z, 4000 SX, 4001, 4002, 4003, 4003C, 4005, 4005 C, 4009, 4010, 4021, 4021 B, 4021 CN, 4021 FN, 4021 J1, 4021 J2, 4021 H, 4021 SC, 4021 SX, 4026, 4031, 4033, 4034, 4035, 4035 SC, 4035 SX, 4037, 4039, 4041, 4100 B, 8800, 4046, 4047, 8801, 8804, 400 B, 4052, 4052 B, 4055 B, 8808, 4021 P, 4035 D, 405 B, 4054 B, 4057 B, 410B, 4061, 4062, 4650, 8805, 8804 S, 4063, 4052 W, 8805 X, 4041 C, 4613, 4810, 400 W, 4047 B, 4069, 405 C, 4035 B, 4805.

One of the most recent ‘El Primero’ adaptations is cased in the Defy El Primero 21 . This development depends on El Primero for the time indication (barrel, going train and oscillator) and works at 5Hz. However, this time indication isn’t driving the chronograph system any longer, which is presently a completely independent instrument with its own energy stockpiling and oscillator. Running at a mind-blowing 50Hz recurrence, the last required a pristine development!

For more information, visit .

Technical details – Zenith El Primero 400B

  • Integrated segment wheel chronograph with programmed winding
  • Diameter: 30.00
  • Height: 6.60 mm
  • Jewels: 31
  • Frequency: 36,000 vibrations/hour or 5 Hz.
  • Balance: annular
  • Balance spring: flat
  • Power hold: 50 hours
  • Winding: bi-directional
  • Parts: 326
  • Functions: hours, minutes, little seconds at 9 o’clock, date, chronograph (focus seconds, hours at 6 o’clock and minutes at 3 o’clock)