The Peseux 7001 is a 2.5 mm Swiss manual caliber that entered production in 1971 and has remained essentially unchanged to this day. When Peseux was acquired by ETA in 1985, production never stopped: this fact alone tells you how much the market continued to want it.
The geometry is simple. Frequency at 21,600 vph, 42-hour power reserve, no complications, no date window. A true time-only. The mainplate and bridges offer wide, clean surfaces, easy to work with: this is why so many independents choose it as their base. Ivan Berets, Minhoon Yoo, Rune Bakkendorff — and before them Michiel Holthinrichs in his early pieces — start from this caliber and redesign everything you see: nickel silver bridges, hand-snailed finishing, black polishing, mirror-polished bevels. The mechanical engine remains; the aesthetics become the builder's.
Blancpain followed the same logic more systematically: its 64-1 caliber, mounted in the Villeret anniversary, is a Peseux 7001 finished to the manufacture's internal standards. Holthinrichs pushed the reasoning further with the HW-M01 caliber in the Deconstructed: the hierarchy of the Peseux 7001's gearing remained as reference, but 75% of the design is new and 50% of the components are of Dutch origin.
Rune Bakkendorff, in the Byrja, uses NOS examples — New Old Stock — never mounted since the 1960s-70s. It's a philological choice: the caliber is used in the form it was conceived, without modifications. The exact opposite of those who take it as a blank canvas.
Modern alternatives exist. Joux-Perret has developed the D100 and D101 calibers — manual, 21,600 vph, 18 jewels, 50-hour power reserve — conceived as more refined successors for ultra-thin watches. Standard finishes are better; the autonomy is eight hours longer. But if you're looking for a NOS example, a consolidated base that an artisan has already worked on for decades, or simply a caliber whose topography you know by heart, the Peseux 7001 has no direct substitute.
From the bench: NOS movements circulating today almost always need complete servicing before being reassembled. The original lubricants have degraded. It's not a flaw in the caliber; it's simply the physics of time.
