Grönefeld - The Geneva Watch Auction: XVIII Geneva Friday, November 3, 2023 | Phillips
  • Manufacturer: Grönefeld
    Year: 2012
    Model Name: One Hertz 1912
    Material: Stainless steel
    Calibre: Manual, G-02, 39 jewels
    Bracelet/Strap: Leather
    Clasp/Buckle: Stainless steel Grönefeld pin buckle
    Dimensions: 43mm Diameter
    Signed: Case, dial, movement and buckle signed
    Accessories: Accompanied by Grönefeld Certificate of Authenticity, fitted presentation box and outer packaging

  • Catalogue Essay

    While the Horological Brothers Bart and Tim Grönefeld may be an unfamiliar name for many enthusiasts, the duo have a cult like following from collectors of independent horology. Over the last decade they have established a strong reputation for creating innovative watches, with a mission to “build elegant timepieces with surprising mechanisms”. The Dutch brothers come from a watchmaking family first established in 1912 by their grandfather Johan Grönefeld, and are passionate for exceptional watchmaking, creating complications that will be cherished for years to come.

    The One Hertz was released in 2010 as the world’s first serially produced watch made with independent deadbeat seconds. While the complication is not unique in horology, it was Grönefeld’s secondary gear train powering the deadbeat seconds that added a novel ideal to modern horology. This dedicated gear train permits seconds to be driven from one independent mainspring barrel, while the hours and minutes are driven from a second mainspring.

    The dial’s unique design expressed the importance of the dead beat seconds with its prominent display of the seconds comprising the majority of the dial, while the time, indicated in a small sub-dial at 2 o’clock, is relegated to a smaller role. A power reserve display in placed elegantly within the seconds subdial and near the 3 o'clock position is the Wind/Set selector. The Brothers have ingeniously created a system where the crown does not need to be pulled out to set time but on the contrary, by pressing the crown the, watch can be either set or wound.

    The bridges and plates of the One Hertz are made from steel as opposed to brass more commonly used in watchmaking, its unique architecture, various finishes and the overall attention to detail make the movement an incredible sight to behold.

    The present One Hertz 1912 in stainless steel is one of the rarest variants of the model ever created as only 12 were ever made.


A cutting edge and innovative stainless steel wristwatch with independent deadbeat seconds, certificate of authenticity, and presentation box, part of a limited edition of 12 pieces

43mm Diameter
Case, dial, movement and buckle signed

CHF30,000 - 60,000 

Sold for CHF69,850

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Alexandre Ghotbi
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+41 79 637 17 24

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Head of Sale, Geneva

+41 79 460 55 88


The Geneva Watch Auction: XVIII

Geneva Auction 3 - 4 November 2023