Rudis Sylva RS12 Grand Art Horloger with Harmonious Oscillator

Rudis Sylva is a small independent Swiss brand which builds only the most complicated watches, or Grand Complications.  More specifically, Rudis Sylva watches are built around a special horological innovation, the Harmonious Oscillator.  Making its Perpetuelle debut, here I examine the brand’s new RS12 Grand Art Horloger, a superlative timepiece with a truly fascinating timekeeping mechanism.  In addition to exploring the watch, I will give you the full run down on the Harmonious Oscillator — cited by a large number of Master watchmakers as the most significant invention since Breguet’s Tourbillon in 1801, according to Rudis Sylva.

Rudis Sylva is quite special in that it offers not only modern day innovation but it is also preserving many of the age-old watchmaking techniques — techniques which are increasingly becoming a lost art.  In short, Rudis Sylva looks to be something really special, and of course something this special doesn’t come cheap:  price is 250,000 Swiss Francs.  Enjoy this closer look.

Rudis Sylva RS12 Grand Art Horloger

44mm red of white gold case (14.3mm thick), manual wind Harmonious Oscillator movement (patent no. 575/09)

The Harmonious Oscillator

The Harmonious Oscillator was first presented at Baselworld 2009 in the RS05 watch.  The Harmonious Oscillator is most simply thought of as a better solution to improving the accuracy of a watch than the tourbillon; in a vertical position, the tourbillon generally needs a minute to compensate for the effects of gravity, while the Harmonious Oscillator counters it completely.  It does this via a resonance system with two mechanically interlinked balances driven by a single escapement.   This innovation goes against conventional wisdom which would suggest avoiding as much stress as possible on the balances.

Dual balance wheels have toothed-edges and are interlinked

This revolutionary regulator featuring two toothed balances is a unique invention minimizing the effects of gravity while boasting highly sophisticated decorative details hand-worked by the region’s finest craftsmen.

Here are other noteworthy technical characteristics of the watch:

  • The two toothed balances are interlinked. This link ensures the same amplitude. The symmetry and energy of the balance springs are constantly opposed, enabling instantaneous average correction in the vertical position, which minimises the effect of gravity.
  • The cage turns 360 degrees in 60 seconds
  • The pallet fork is positioned at 90 degrees
  • The double barrel ensures a power reserve of 70 hours
  • The frequency is 21,600 vibrations/hour (3 Hz)

Fore more discussion of the claimed superiority of the Harmonious Oscillator vs. the Tourbillon, please visit this discussion on Rudis Sylva’s facebook page.

You can see the Harmonious Oscillator in action in the following video, as well as many of the other techniques which I also describe below (engraving, guilloche, oven-fired enamel).

Rudis Sylva Video


Seconds indicator bridge
Machined from titanium and hand-bevelled, this bridge at 6 o’clock includes no fewer than 28 internal angles.  Rudis Sylva states that it takes 10 times longer to create a sharp internal angle in titanium than a rounded corner in steel.


The lower part of the main plate features a hand-crafted guilloche decoration of tapering pyramids. From the edge to the centre of the piece, each guilloche line includes 60 pyramids, each one smaller than the one adjacent it.  Guilloche work is performed by master craftsman Georges Brodbeck in his Saignelégier workshop.

Apparent in the marking on the double barrel bridge or the caseback sundial and inscription, the extremely precise engraving magnifies the skill of the hand-engraver whose painstaking work is carried out under microscope.  Given technology-driven advances in mechanical or laser engraving, only pieces such as this which are given the craftsman’s hand touch make them pieces of haute horlogerie of the highest order.

Rudis Sylva relies upon artisans Sylvain Bettex and Bertrand Degiorgi (seen in video) to apply their finest work to the RS12.  Purists will appreciate the chisel work, which cuts to the heart of the flawless lettering with regular bevelling and perfect symmetry, revealing moreover a polished cut completely free from burrs.  The hand craftsmanship here is hard to beat.

Oven-fired enamel
Silica stones are crushed by hand and mixed with water by artisan Sophie Cattin Morale.  Dried out and then fired in a kiln at around 840 degrees, the enamelled half-moon is honed to obtain a flat surface, and then placed back in the kiln to undergo a final operation, known as glazing.  After the enamel surface has been vitrified to give it a shine, it undergoes a final polish.

hand-engraved sundial with oven-fired enamel

The unique technology, if working as advertised by Rudis Sylva, would in fact position the Harmonious Oscillator above most existing tourbillons, since the effects of gravity to which it is subjected are minimized more efficiently. The hand-finishing makes each piece unique and pays tribute to the various branches of watchmaking artistry.

Harmonious Oscillator “FAQ” (per Rudis Sylva)

The Harmonious Oscillator is neither a tourbillon nor a carrousel; however they do have some aspects in common:

  • Each mechanism is mounted on a rotating cage which completes a full revolution in 60 seconds.
  • The system improves accuracy by counterbalancing disruption of the balance isochronism due to the Earth’s gravity.

What are the major differences between the Harmonious Oscillator and a tourbillon or carrousel?

  • The 3 devices have a complete balance. In the tourbillon, the balance staff is situated on the same line as the tourbillon cage pivots, whereas in the carrousel, the balance staff is eccentric. These two systems take one minute (a full revolution) to compensate for loss of accuracy in the vertical position (effect of gravity).
  • The Harmonious Oscillator, by means of the interconnection of the balances and asymmetric deployment of the mainsprings, enables instantaneous time correction in the vertical position. In the same position, the tourbillon – provided it is in a totally stable position – needs a minute to correct.

In conclusion, the Harmonious Oscillator offers far better accuracy than most conventional tourbillons or carrousels. This mechanism is close to perfection in terms of time-keeping precision.

Price is 250,000 Swiss Francs.  Available at Westime Westime Beverly Hills here in the USA: 254 North Rodeo Drive, Beverly Hills, California 90210, Tel. +1 (310) 271 0000 — be sure to tell them Perpetuelle sent you.