As the few years that have passed since our initial compendium on Audemars Piguet’s 13 ligne “VZ” movement have given us the opportunity to further examine a variety of examples of the movement in detail, I felt it was the perfect time to revisit the subject with a specific focus on the technical and aesthetic evolution of the VZ from its early days of use until the last movement left the bench in 1959.

For roughly 60 years after it’s introduction in 1916, the 13”’ Valjoux filled the role of both versatile work horse and purpose-built thoroughbred and was festooned with a variety of complications ranging from the simple, single pusher chronograph the movement was conceived as, to impeccably executed perpetual calendars and beyond. The versatility of the movement was fully embraced by Audemars Piguet who used it in both highly complicated applications all the way down to time only pieces. Patek Phillipe reserved the VZ for its most important complications and clients. AP’s chronographs of this period are without a doubt superb, and generous space has been afforded them in scholarship, most recently in AP’s own ‘Complicated Wristwatches’ book. Just as fascinating but much less known are the approximately 2000 time-only watches equipped with Audemars Piguet VZ movements produced by the maison from the late 1930s until 1959.

The VZ of Audemars Piguet is of the same lineage as the well known Valjoux 23/72 with a key difference. While there isn’t much to visually differentiate, for instance, Valjoux 23s used by difference brands, the first impression given by the VZ is strikingly different outside its basic geometry, and for good reason. Rather than purchase the movement as an ebauche —essentially a ready made kit from which a fully functioning watch could be assembled — AP purchased from Valjoux what was known as a movement blank. The blank consisted of the structural elements of the movement with only basic machine work completed. All components outside this framework were supplied by Audemars Piguet or a vast number of highly specialized contractors, allowing the movement to be constructed to a remarkably high standard. The system of collaboration long present between the small shops in the valley and known as the établissage system was essential to the existence of the VZ as envisioned by AP.

While the basic geometry of the movement never changed during its twenty year run, we see several technical upgrades as well as variations in finishing.

1942 VZASC

The earliest VZ were used in complicated watches during the 1930s and were mercury gilded, a technique that involved applying a heated mixture of mercury and gold to the surface of the movement leaving a gold gilt finish. By the early 1940’s when we see some of the earliest time only VZ appear, AP had ceased the use of mercury gilding in favor of German silver plating seen above. Here we see a wonderful example of the capability of the maison’s master engravers in the artfully executed movement nomenclature. Also pronounced is the anglage work and deeply chamfered jewel sinks, and somewhere along the way AP found cause to include two more jewels, bringing the total jewel count to twenty (20). Note the lack of shock protection on the balance cap, as well as the simple regulator mechanism.

1945 VZSS

Sometime in the mid-1940’s the crown and its respective parts swapped sides with the ratchet wheel and barrel, bringing the balance wheel directly opposite the crown. This change moved the fourth wheel from the 9 o’clock position to 6 o’clock, a configuration designated the VZSS (VZ, secondes subsidiaires).

Four distinct configurations were used during the ‘40s; the VZSS, a sub-seconds variation and most common relative to the others, the VZSSC, a center seconds version, the VZASC, an earlier center seconds version based on the VZA, and the original iteration VZA with seconds at 9 o’clock. The VZA retained the geometry of the original chronograph, hence the position of the seconds, and was used exclusively in Audemars Piguet’s rare Precision and Worldtimer lines. While we don’t have an exact production figure on either of these models, knowing that Audemars Piguet’s 307 chronographs all contained VZAs, we can be reasonably sure production didn’t exceed 250 units, and was more than likely sub 200.

1947 VZSS

The late 1940s brought more change to the platform. Gone was the exuberant hand-engraved nomenclature boldly emblazoned in the center of the broad plate which, for reasons unknown (perhaps a simple change in engravers), was replaced with a much simpler text and was relegated to the periphery. In what was likely an effort to maximize production efficiency, the previously independent fourth and escape wheel cocks were merged into a single bridge.

1949 VZSS stop-balance

Around the time Audemars Piguet moved to serialized production in 1951 another interesting take on the VZ emerged. During this period AP began equipping a small number of watches with a simple hacking device that worked via a small button at 9 o’clock. When the wearer depressed the button a small spring gently stopped the balance wheel. This feature can be found on both reference 5051 and 5065, although the vast majority of these references did not include it. Technically speaking, this feature should be viewed as a complication, but I’m addressing it here because it doesn’t fit well in any other category and is rarely discussed. Total production of stop- balance watches in all metals is almost certainly not more than 250, but more than likely sub-200, making it rarer than most, including Patek Philippe’s hallowed reference 1518.

1952 VZSS

The final iteration of the VZ came about in the early 1950s just after the move to serialization. Technical enhancements came by way of an upgraded micro-regulator and the addition of shock protection to the balance. We also see a move back to the fine engraving and bold, styled nomenclature of the previous decade.

1954 VZSS

In 1953 Lucerne based jeweler and watchmaker Gübelin approached Audemars Piguet to supply 200 VZ movements (100 VZSSC and 100 VZSS) for use in a special series of watches released to commemorate the marque’s jubilee anniversary in 1954. I believe this is the only non-Audemars Piguet branded application to contain AP-made VZ movements. It wasn’t a terrible surprise that Gübelin turned to Audemars Piguet for the important occasion. The two companies had a history of collaboration stretching back decades during which time AP supplied them with both completed watches and loose movements.

The end of the 1950’s marked the close of an era largely defined by the versatility of the VZ as Audemars Piguet transitioned its focus to the ultra-thin concept. The VZ in its many forms occupies an important space in Audemars Piguet’s timeline of rich history, and although watches containing the venerable movement represent a true grail for some, it remains undervalued relative to it’s more plentiful counterparts. And for the swathe of collectors disenchanted with the the mainstream, this seldom explored horological tributary remains an abundant source of intrigue and enjoyment.

1959 VZSSC, one of the final 50 produced