Zenith El Primero A3817 - Only 1000 made

This Zenith El Primero A3817 from 1971 is one of the rarest and most fascinating references from the early history of the legendary El Primero. It uniquely combines two of the most characteristic designs of the first El Primero generation: the distinctive, angular tonneau-shaped case of the A384 with the famous three-color dial configuration of the A386. With only around 1,000 examples produced, the A3817 remained an exceptionally rare model and is today one of the most sought-after early El Primero references.

Zenith had introduced the El Primero only two years earlier, in 1969. The revolutionary automatic chronograph movement was among the first of its kind and distinguished itself in particular through its exceptionally high frequency of 36,000 vibrations per hour. The A3817 therefore originated during that brief and particularly exciting early period in which Zenith experimented with different case shapes and dial designs. It is precisely this combination of technical innovation and highly distinctive design that makes the reference so interesting today.

The exceptional original dial is undoubtedly one of the highlights of the A3817. Set against a cream-colored background are the three characteristically overlapping subdials in different shades of grey and blue. At 3 o’clock is the dark blue 30-minute counter, at 6 o’clock the anthracite 12-hour counter, and at 9 o’clock the running seconds in a lighter shade of grey with a blue scale and blue seconds hand. Together with the central red chronograph hand, this creates an unusual color combination that immediately recalls the A386 while giving the A3817 a character entirely of its own.

A particularly distinctive detail can be found in the outer minute track. The fine triangular markings form the so-called “Shark Tooth” scale, a feature closely associated today with the rare A3817 and A3818 references. This fine graduation is not merely an interesting design element, but also directly corresponds with the high frequency of the El Primero movement and its ability to measure tenths of a second.

Another special feature is the dark grey outer scale. It combines a tachymeter marked “TACHYMETRE – BASE 1000” with a pulsometer marked “PULSATIONS – BASE 15”. Despite the multitude of indications, colors and scales, the dial remains remarkably well balanced – a fine example of Zenith’s creative approach to design at the beginning of the 1970s.

Over the decades, the original luminous material has aged to a distinctive dark green tone. This aging is part of the watch’s authentic state of preservation, and the luminous material has not been renewed or altered. Together with the slightly warm tone of the dial and the differently colored subdials, it emphasizes the untouched vintage character of this example.

No less characteristic is the tonneau-shaped stainless steel case. The A3817 uses the angular case architecture known from the A384, with its short integrated lugs and pronounced geometric surfaces. The preservation of the original finishes and edges is particularly important to the appearance of these cases. On this example, the characteristic surfaces and case geometry remain very well preserved despite normal signs of wear. The correct engravings on and inside the caseback further underline the originality of the watch.

Completing the watch is its original Gay Frères stainless steel “Ladder” bracelet – one of the most characteristic bracelets associated with the early Zenith El Primero. The famous ladder bracelet not only perfectly complements the angular case visually, but is also period-correct for this particular example: the clasp is dated 1/71 and is accompanied by the correct ZKM end links. Especially on a rare reference such as the A3817, a period-correct original bracelet is an important part of the overall package.

Inside is the legendary Zenith caliber 3019 PHC, the original El Primero movement. This automatic chronograph caliber features 31 jewels, a column-wheel mechanism and operates at an exceptional frequency of 36,000 vibrations per hour, or 5 Hz. This high frequency allows the chronograph to measure tenths of a second and was technically extraordinary at the time of its introduction. The caliber also features a date display positioned between 4 and 5 o’clock – a detail that remains one of the characteristic features of the El Primero to this day.

The A3817 occupies a special place within the early history of the El Primero. It is neither simply an A384 with a different dial nor an A386 in a different case. Instead, it combines elements of both icons while adding distinctive features of its own, such as the Shark Tooth minute track, the combined tachymeter and pulsometer scales, and the unique execution of the running seconds. With a production of only around 1,000 examples, this extraordinary design was also made in very limited numbers.

In the configuration presented here, with its original dial, exceptionally well-preserved case and original Gay Frères Ladder bracelet, this A3817 represents a particularly coherent and authentic example of one of the most fascinating Zenith references of the early 1970s.

Condition Report
Dial: great condition - light, natural patina - original tritium luminous material in hands and hour markers, aged to a dark green tone - applied Zenith logo (star) - signed "ZENITH CHRONOGRAPH AUTOMATIC El Primero" and "SWISS MADE T".

Case: great condition - worn but unpolished - original finish intact - clearly preserved serial number engraving on the caseback - correct original Zenith crown with star logo - correct engravings inside the caseback, including "SP 1301" (Spillmann case).

Movement: automatic Zenith El Primero caliber 3019 PHC with quick-set date - timegrapher results: rate -1 s/day, beat error: 0.4 ms, amplitude: 298° - chronograph starts, stops and resets perfectly.

Bracelet: original Gay Frères stainless steel Ladder bracelet - correct ZKM end links - Zenith folding clasp dated 1/71 - slight loss of tension - hardly any signs of wear - bracelet length adjustable between 18 and 25 cm.

Serial number: 905Dxxx

Int.Exe.: 7963671