Timekeepers Club / September 5, 2023

Ferdinand Berthoud Chronomètre FB 3 Only Watch

For its second participation in Only Watch, Chronométrie Ferdinand Berthoud is offering a new version of the FB3 collection: a one-of-a-kind model presented in a patinated bronze case, a tribute to the ‘Master Watchmaker’ title granted to Ferdinand Berthoud just 270 years ago.

The five one-of-a-kind models in the FB 1R Regulator collection unveiled in 2018 generated considerable enthusiasm at the time of their launch. Their bronze cases featured five different patinas, as if they had just emerged after a long stay in the underwater depths – a tribute to the world of onboard marine chronometers once developed by Ferdinand Berthoud himself.

Since then, Chronométrie Ferdinand Berthoud has unveiled new movements, the latest of which powers the FB 3 collection. The conditions were therefore ripe for the creation of a model that would unite these latest developments: a one-of-a-kind timepiece in patinated bronze, driven by a balance with a cylindrical balance-spring chronometercertified by the COSC. Thus emerged the idea of the Chronomètre FB 3 "Only Watch", which will be put up for bidding at the eponymous auction to be held in Geneva on 5 November.

One-of-a-kind anniversary model

Several months of preparation and testing were necessary to achieve the patinated bronze case of the Chronomètre FB 3 Only Watch. The colour and nuances are unprecedented and evoke to the discerning gaze the patina that naturally develops on the copper alloys of the precision and navigation instruments supplied by Ferdinand Berthoud during the 18th century.

This patina symbolises the passage of time and celebrates an anniversary: in 1753, exactly 270 years ago, Ferdinand Berthoud received the ‘Master Watchmaker’ title, at the age of just 26. This one-of-a-kind anniversary watch will be offered at the tenth edition of Only Watch. This is a rare opportunity, as the current capacities of the Chronométrie Ferdinand Berthoud workshops only allow for the production of around 30 timepieces in this collection per year.

Beating inside the FB 3 "Only Watch" model is the world’s only calibre with a cylindrical balance-spring officially chronometer-certified by the COSC, a clear tribute to the quest for precision initiated by Ferdinand Berthoud. Many months of research, testing and fine-tuning were necessary to define the number of coils and the geometry of the terminal curve at the attachment points. This new mechanical hand-wound movement stems from more than three years of research and development. Appearing at 9 o'clock, the three main escapement organs – the balance-wheel, pallet-lever and escape-wheel – are thus individualised, distinct and prominent. This ample space dedicated to the regulating organ enables its operation to be admired in full, and the cylindrical balance-spring to be seen beating throughout the three-day power reserve, including through a large porthole created in the case middle at 9 o'clock.

Colour filiation

The finishing associated with the FB 3 "Only Watch" model (ref. FB 3SPC.5) is tailored to reflect the colour codes of the 2023 edition of this charity auction. More than 100 hours of work were required to decorate the movement, which features 3N yellow gilded components. The blue colour is picked up on the gold hands with CVD treatment. Pink hues are found on the jewels visible on the dial side. Two straps will be delivered with this one-of-a-kind model: an aged calf leather strap recalling the patina of the case; and a dark green alligator strap in harmony with the Only Watch 2023 colour chart. The caseback features a special "ONLY WATCH PIECE UNIQUE" engraving recalling the exceptional character of this creation.

Technical specifications

Ferdinand Berthoud Chronomètre FB 3 Only Watch

Reference: FB 3SPC.5

Unique (one-off) piece made for Only Watch 2023 charity auction


  • Material: Brown patinated bronze
  • Diameter: 42.30 mm
  • Thickness: 9.43 mm
  • Crown diameter: 8.50 mm
  • Crown in brown patinated bronze with FB logo in titanium
  • Glass: Domed sapphire crystal glareproofed on both sides
  • Exhibition back in sandblasted titanium fitted with a glareproofed sapphire crystal pane
  • Water resistant to 30 metres

Dial and hands

  • Eggshell-coloured peripheral inner bezel ring for the hours and minutes, in sandblasted silver-toned brass
  • Eggshell-coloured seconds subdial at 6 o’clock, in sandblasted silver-toned brass
  • Sandblasted and 3N gilded visible components of Calibre FB-SPC
  • Transparent sapphire ‘porthole’ at 9 o’clock
  • Facetted and skeletonised and open-tipped hours and minutes hands in 18-carat gold with blue CVD treatment
  • Seconds hand with counterweight in 18-carat gold with blue CVD treatment
  • Arrow-shaped power-reserve hand in 18-carat gold with blue CVD treatment


  • Calibre FB-SPC
  • Mechanical hand-wound movement
  • Diameter: 37.30 mm
  • Thickness: 9.89 mm
  • Lignes: 15 ’’’
  • Number of jewels: 47
  • Frequency: 21'600 vph (3 Hz)
  • Power reserve of 72 hours
  • Number of components: 230
  • Number of bridges: 16


  • Central display of the hours and minutes
  • Seconds at 6 o’clock and power reserve at 2 o’clock

Strap and buckle

  • Two straps (125 x 70 mm – Other sizes available on request):
  • - Dark green alligator leather strap
  • - Chestnut brown aged calfskin leather
  • 18 mm pin buckle in sandblasted titanium


  • CHF 160'000 - 180'000

For more information, please visit and


Leave a comment

You must be logged in to post a comment Login / Sign up