The Zenith El Primero and the Race to Build the First Automatic Chronograph

The late 1960s witnessed horology's great race: three groups worked to produce the first automatic chronograph. Zenith in Le Locle, the Chrono-Matic consortium, and Seiko each took different approaches. Zenith's El Primero, unveiled January 10, 1969, was the first to fully integrate the chronograph within the movement.

The El Primero beat at 36,000 vibrations per hour, five hertz, compared to the standard four. This allowed measuring elapsed time to one-tenth of a second, unprecedented precision. The 278-component movement remained compact enough for a standard case (https://www.zenith-watches.com).

Five hertz is not free. A faster balance averages out positional error and lets the chronograph resolve a tenth of a second, but it also runs the escapement through more cycles per day, so high-beat movements have conventionally been serviced at the shorter end of the five-to-ten-year interval and demand better lubricants. The modern 3600 calibre goes further and drives the chronograph seconds hand once around the dial every ten seconds, so a tenth is read directly off the scale rather than estimated between marks.

The El Primero nearly perished during the quartz crisis. When management ordered destruction of all mechanical tooling, watchmaker Charles Vermot secretly hid the dies and drawings in the factory attic. When the mechanical revival began in the 1980s, Vermot's contraband allowed resumed production.

Rolex provided the most prominent showcase. From 1988 to 2000, a modified El Primero powered the Daytona, regulated down to 28,800 vph for longevity. This partnership validated the movement's reliability and introduced it to an audience that might never have encountered Zenith.

The modern family spans the Chronomaster Original with signature tri-colour subdials, the Defy El Primero 21 measuring to one-hundredth of a second, and the Chronomaster Sport targeting everyday luxury chronograph buyers with a tachymeter bezel.

The dimensions matter more than the specification sheet suggests. The Chronomaster Original is 38 millimetres, following the 1969 A386's proportions, and its short lugs make it one of the few current chronographs that suits a wrist under 17 centimetres. The Chronomaster Sport is 41 millimetres with a ceramic bezel graduated to a tenth of a second and wears substantially larger. Try both before assuming the heritage piece is too small; the A386 case was drawn when a chronograph was a tool worn under a cuff.

On the wrist, the high-beat movement produces smoother chronograph hand sweep than lower-frequency alternatives. The tri-colour dial is instantly recognisable, giving the watch a retro-modern personality transcending current trends.

The vintage market divides sharply. An original A386 with overlapping grey, blue and anthracite registers is a five-figure watch at auction, and the dial is where the money sits: check the three subdials have aged as a set, since a replaced disc is a common fault and an expensive one to put right. Note also that Zenith resumed El Primero production in 1984 using Vermot's rescued tooling, so the name on a dial does not by itself date a watch to the 1970s. The reference number does.

The El Primero represents engineering persistence: from the race to be first, to the attic rescue, to the Rolex partnership proving its mettle. For an automatic chronograph with genuine significance and manufacture credentials, the Chronomaster Original in steel offers exceptional value.