And The Winner Is …

At Geneva Watch Days, the COSC – the largest non-profit organization when it comes to testing movements and watches – gave visitors the opportunity to regulate a mechanical movement in the open competition called the Calibership Challenge. Of course I could not pass on such an opportunity. Thus, I found myself seated at a watchmaking bench in the pavilion on the lakeshore, with a magnifying loupe placed over my right eye. With quite steady hands and the guidance of an apprentice from the Geneva School of Watchmaking, my instructor for the occasion, I tried my best to make the tiny regulations that makes the difference between a movement being more useful for scrap metal or a precision timekeeper.  But I admit it. I failed miserably. Let’s put it this way: I should not give up my day job writing about watches and start working at the bench. Theoretical cosmologist Katie Mack, who was in Geneva to partake in a GWD panel about the nature of time, however managed to regulate her movement with remarkable precision. After a thorough 15-day test in different positions and temperatures in COSC’s laboratories, she was crowned the winner of the Calibership challenge. She achieved an average daily rate of +0.77 seconds/day. This is way beyond not only the –6+4 seconds per day that is the “normal” COSC standard, but also the new COSC Excellence standard of –2+4 seconds deviation per day. 

At their exhibition stand COSC also gave live demonstrations showing how the magnetic fields found in everyday life can disrupt the rate of a mechanical watch. Because that is the everyday reality of a watch – in our society we are surrounded by magnetic fields form smart phones, earbuds, bag clasps, Bluetooth speakers, and other quotidian gadgets. Once “infected” by magnetism a watch needs to be demagnetized to return to its original precision. The “danger” of magnetism was also a very hands-on way to show one of the new criteria in the COSC Excellence: resistance to 200 gauss magnetism. This level of resistance would protect your watch from most every-day magnet contacts, but you should still be wary of the very strong magnets to be found in, for instance, large speakers and amplifiers.

If you take care of a watch and service it at regular intervals, few, if any, products can rival its longevity. Thus, it makes sense that an organization like COSC is in it for the long run, and helping the industry with the most important thing for the industry to flourish: future watchmakers. Not only does COSC take on apprentices from The Geneva School of Watchmaking, they also donated a sculpture one-of-a-kind sculpture made from the winning movement of the 2025 Calibership Challenge. (The winner of the Calibership Challenge 2025 was Yannick Nardin, my predecessor here at WorldTempus.) The sculpture was sold for a remarkable CHF 13,000, going into a fund that will help support students at the Geneva School of Watchmaking facing financial hardship. As COSC likes to express it. “Precision is measured. Excellence is passed down.”