NAARDEN, the Netherlands — Pim Koeslag clearly recalls a conversation he had in 2002 with the Dutch watchmaker Christiaan van der Klaauw. “Christiaan said, ‘Well, why don’t you just go to Switzerland, gain some experience and then maybe one time you can come back and work together with me.’”
He followed that advice. And in 2022, years after Mr. van der Klaauw’s retirement, Mr. Koeslag returned as a master watchmaker and majority shareholder to lead the technical and commercial development of the brand.
“I always felt like a failure — until the moment I entered watchmaking school,” said Mr. Koeslag, 41. “The thing is — at school it was always difficult, as I am very dyslexic.”
He entered Zadkine Vakschool in Amsterdam to study jewelry making, but then found it had watchmaking in its curriculum and changed programs. “Finally I experienced something that worked in my mind,” he said. “Letters never did anything for me, but once I saw the wheels turning in watchmaking class it made sense.”
It made so much sense that, in the intervening years, he created 30 movements and now is listed on nine patents as an inventor.
Mr. Koeslag’s career took off at the age of 21 when he — as Zadkine’s best-in-class graduate — was hired by Frederique Constant Group in Geneva to develop a new hand-wound movement. And by 2006, he was leading the group’s watchmaking department.
The man behind Mr. Koeslag’s rapid advance — whom he called “the most important mentor in my career” — was Peter Stas, the group’s founder and chief executive.
Mr. Stas said he chose Mr. Koeslag because “he has an ability to see in three dimensions how the components and wheels are functioning inside a watch caliber.”
Mr. Koeslag described his ability like “3D-imaging, but inside my head.”
For example, he recalled the development of a minute repeater tourbillon with more than 400 components for Ateliers deMonaco, the high-end brand in the Frederique Constant Group: “Lying in bed at night, I could play it around inside my head. I took away components, put new ones in, and I could see what happened. If you have a spring, you make it work, what happens? Where is the friction point, where is the most power?”
A few times, he said, he has even put computer engineers to shame when a watch’s prototyping phase has proved his vision to be correct and the engineers’ calculations to be faulty. “I cannot really explain it, but in my mind it works.”
Which personal horological achievements does he value most? He began talking about two perpetual calendar watches.
One, for Ateliers deMonaco, involved making a super complex timepiece super easy to use: “I was inspired by my old digital Casio watch, where you push a button until something blinks — and then you can set it.”
A mechanical version was enabled by “a selector at 6 o’clock that, once activated, lets you change date, week or month with a single push,” he said, noting that it took him a year or two of sleepless nights to figure out the construction.
For the group’s affordable brand Frederique Constant, the challenge was different: to create a solid and elegant perpetual calendar that would sell for less than 10,000 Swiss francs ($10,785).
Reducing the number of components and perfecting the manufacturing process became the money-saving solutions for the Frederique Constant Highlife Perpetual Calendar (9,250 Swiss francs). “Normally a perpetual calendar movement is very complex to assemble,” he said. “But with this one, you can just put the calendar in place, fix it with four or five screws, and then it works. No adjustment needed.”
After two decades in Switzerland, Mr. Koeslag and his wife wanted to return to the Netherlands with their three children. So, when the opportunity to acquire 75 percent of the van der Klaauw brand appeared, he did not hesitate.
The brand, founded by Mr. van der Klaauw in 1974, is famous for its astronomical watches and clocks. After his retirement in 2009, Daniël and Maria Reintjes took over the company and transformed what had been a one-man show in a garage into an international brand with retailers on three continents, recognized as an haute horlogerie brand by the Fondation de la Haute Horlogerie in Geneva and builder of the Van Cleef & Arpels Midnight Planétarium and Lady Arpels Planétarium.
“Daniel and Maria also won the Grand Prix d’Horlogerie de Genève in 2021, with the Christiaan van der Klaauw Planetarium Eise Eisinga,” Mr. Koeslag said. “Winning the Grand Prix is a big deal for a watch brand, especially an independent one.” The winning watch featured a specialty of the brand: what it described as the smallest mechanical planetarium in the world, measuring just 12 millimeters (about half an inch). Placed at 6 o’clock, the hand-painted depiction of six of the solar system’s planets circulate around a golden sun — a round trip ranging from 88 days for Mercury to 29.4 years for Saturn.
And the Grand Prix has been a big deal for the brand: 2022 sales totaled 220 watches, 175 percent more than in 2021 — and, based on confirmed orders, 2023 is expected to total 400 watches.
“Pim is an excellent match for us,” said Mr. Reintjes, 60, who continues to hold the position of chief executive there. “He has the 20 years of knowledge from Geneva, and he is a watchmaker. Also, he is a young guy from a new generation. We need this for the continuity of the company to secure our legacy.”
Since Mr. Koeslag started his new position in June 2022, the brand has moved from an industrial site about two hours’ drive north of Schiphol airport to a new renovated headquarters in the picturesque town of Naarden, 14 miles east of Amsterdam. The brand, which now has seven employees in addition to Mr. Koeslag and the Reintjeses, occupies an upstairs wing of the former munitions storage site.
As of June 1, the headquarters will be open to the public, although reservations will be required. Visitors first may view an exhibition of clocks and watches from the brand’s 49-year history and then, through glass walls, be able to see the watchmakers in the brand’s two workshops. “It’s like a restaurant with an open kitchen; you can really see what is happening, what is being made,” Mr. Koeslag said.
The brand uses Swiss-made movements, but all the parts for the astronomical complications are made and decorated in the workshops. “We don’t use CNC machines,” Mr. Koeslag said, referring to programmable units. “The machines we have are at least 60 years old — they were used already by Christiaan in his garage when he started.”
But Mr. Koeslag said he loves using such traditional tools and sees them as part of the company’s heritage: “Today I am honored that I can take care of and develop the brand, hopefully for the next 30 years.”