Open Heart | Date | 1810 | Gold

Sílvio Pereira

8 hours ago

5 min read

Series: GREAT COMPLICATIONS

By: Sílvio Pereira

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Technical data

Lépine-type pocket watch in 18 kt gold, from 1810, Date and open heart

- Hours and minutes at 6 o'clock

- Date at 9 o'clock

- Cock (balance bridge) and balance visible at 12 o'clock

- Painted country landscape at 3 o'clock

- Serial number: 2592

- Manufacture: Anonymous

- Country: Switzerland

- Calibre: Double plate. Unnumbered

- Movement protection: Gold case back

- Escapement type: Verge (crown wheel)

- Balance: brass with hairspring, with the cock on top, visible through the dial

- Power reserve: 30 hours

- Frequency: 18,000 vph

- Jewels: None

- Case material: 18 kt gold

- Dial: enamel with no flaws or hairlines

- Small seconds: None

- Pendant: At 12 o'clock

- Case diameter: 50.0 mm

- Thickness: 20.0 mm

- Weight: 83.61 g

- The mainspring is wound by key, directly on the mechanism through an aperture in the dial

- Hands: Breguet style. Set directly on the hand arbor through the dial

- Numerals: Hours - Breguet type. Minutes - indices in a chemin de fer track

- Glass: In excellent condition.

- Case number: 2592

Overall assessment - A grand complication watch, more than 210 years old, in immaculate condition.

Innovation, technical complexity and rarity

In terms of innovation, this watch brought permanently into view, set in the dial yet still protected by the glass, its “heart”: that is, its balance bridge (the cock) and the balance itself, with its successive alternating oscillations, almost hypnotic, which so delight lovers of mechanical watchmaking. In essence, consciously or not, the creator of this feature gave watches “life”. Normally, we only know that a watch is running if we hold it to our ear to hear its characteristic tick-tock or, where there is one, by the movement of the seconds hand. From this innovation onwards, watches with this feature came alive, since it allows us not only to enjoy the to and fro of the balance but also to check whether the watch is running or not.

Nowadays, with the sophisticated technology at our disposal, it seems a relatively simple complication to execute, but more than 200 years ago, with the limitations inherent in the absence of technology supported by sophisticated electronic and computing resources, the simple fact of making the bridge and balance assembly visible on the dial was an achievement of extreme complexity.

From the mid-16th century, the balance wheel and hairspring assembly was placed on the second plate and was held and protected by its bridge, also known as the “cock”. This assembly could only be seen from the back of the watch, by opening the cover or covers that protected it.

Typical 17th-century watch with the balance and its “cock” seen through the back of the watch.

Technically, it was very difficult to invert the whole mechanism and place the bridge and balance assembly on the front of the plate, where the dial was fixed. First, and perhaps the greatest difficulty, was changing the paradigm, since it was firmly established among the watchmakers of the time that it made no sense for this mechanism to be on view to all; then came the technical difficulty of altering the entire organic structure of the watch's mechanism. With the inventiveness, tenacity and resilience that characterise watchmakers, someone thought of challenging the paradigm and doing something different, forcing a change in mentalities, bringing beauty to the watch and giving it “life”. Thus was born the first “Open Heart” in the history of watchmaking.

The creators' intention would have been to do something different that would touch users but, as with almost everything where watchmaking is concerned, the greatest inventions would only come to be appreciated and applied some centuries later, and the open heart is no exception. There are no accounts of any other such watch having been produced for around 100 years, until the Swiss company Hebdomas, at the end of the 19th century, took up the concept and placed the heart of the watch on the dial, in full view.

At the beginning of the 20th century, the Swiss company Corvoisier Fréres, drawing on Breguet's invention from the end of the 18th century, created a tourbillon and placed the cage containing the escapement and balance assembly on the dial of the watch.

Pocket tourbillon made by Corvoisier Fréres for Tiffany in 1905 (from the author's collection)

After exhaustive research by the author, it was not possible to identify any other example identical or similar to this watch, which leads us to suppose that either it is a unique piece or there are, possibly in private collections, very few examples, which makes this watch very rare and, consequently, quite valuable.

Hebdomas | 1902 | Silver

https://video.wixstatic.com/video/a1ba6b_1c31a700238043fb9638d2a29048cec7/720p/mp4/file.mp4

Technical data

Lépine-type pocket watch in silver, from 1902, open heart and 8-day power reserve.

- Hours and minutes at 12 o'clock

- Balance bridge and balance visible at 6 o'clock

- 8-day power reserve

- Serial number: None

- Manufacture: Hebdomas

- Country: Switzerland

- Calibre: Classic bridges. Unnumbered

- Movement protection: Silver case back

- Escapement type: Swiss lever

- Balance: Bimetallic, temperature-compensated, with Breguet hairspring

- Power reserve: 30 hours

- Frequency: 18,000 vph

- Jewels: 15

- Case material: Silver

- Dial: enamel with no flaws or hairlines

- Small seconds: None

- Pendant: At 12 o'clock

- Case diameter: 43.8 mm

- Thickness: 15.4 mm

- Weight: 65.61 g

- The mainspring is wound by the crown at 12 o'clock

- Hands: Pear-shaped. Set by the crown, with the stem released by a push-piece at 11 o'clock

- Numerals: Hours - Roman. Minutes - indices

- Glass: In excellent condition.

- Case number: None

Overall assessment - Watch with an eight-day power reserve, visible balance and balance bridge, in excellent condition.

The Open Heart today

This innovation was never much appreciated by the most prestigious watch manufacturers; it is somewhat hard to understand, but that is the reality. In our view, a window in the dial that lets the heart of the watch be seen gives it dynamism and makes it “alive”. It is a matter of choice...

Of these, only Zenith and, to a somewhat lesser degree, Rado have ventured into this area. Below we present some brands that have stood out for offering this feature in some of their models.