Valjoux

Valjoux is not a watch brand: it is an ébauche manufacturer founded in Les Bioux, in the Vallée de Joux, which for nearly a century supplied chronograph movements to practically every notable watchmaking house. From the Valjoux 23 of 1916 to the 7750 of 1974, this line of calibres defined the architecture of the modern mechanical chronograph more than any other manufacturer.

The Valjoux 23 is the starting point. Thirty-eight millimetres of gross diameter — no, wait: 29.5 mm by 5.8 mm thick — nine-pillar column wheel, large balance, Y-shaped central bridge. From 1916 to 1974, adopted by Patek Philippe, Audemars Piguet, Vacheron Constantin. In 1938 the Valjoux 72 was born, a direct derivative of the 23 with the addition of a 12-hour totaliser: three counters, manual winding, 18,000 vibrations per hour until 1960, then updated to 21,600 in the calibre 726. The 72 equipped Heuer, Rolex, Tudor and dozens of minor houses. It was the standard engine of the quality chronograph in those years.

Alongside these existed lesser-known but technically interesting variants. The Valjoux 88 added a moon phase and triple calendar to the 72. The Valjoux 65, sixteen lines, was used by Eberhard as the base for its rattrapante, renamed calibre 16000. The V23 family — with the 234, 235, 236 and 237 variants — declined flyback and calendar functions in combinations that are quite rare on the secondary market today. The Valjoux 92 is immediately recognisable by its oscillating pinion, which drives the minute totaliser: a constructional detail that collectors quickly learn to identify.

In 1974 ETA, already part of the ASUAG Group as Valjoux, introduced the 7750: automatic chronograph, rotor winding, cam activation rather than column wheel. The choice of cams was pragmatic — robustness, ease of servicing, production cost — not a technical compromise. The system works well, though purists still prefer the column wheel for the smoothness of its transitions. From the 7750 came the 7751 with full calendar, the 7753 with 3-6-9 counters, and the more recent A05, which revisits that symmetrical layout. Sellita built its own SW510 on the same architecture. Joux-Perret, with the L111, followed a similar evolutionary path. Chinese clones such as Liaoning Peacock's SL4617 replicate the 7750 layout for the entry-level market.

At the bench I have seen Valjoux 72s in impeccable condition after sixty years of service, and 7750s worn out after ten. The difference often lay in the care of the owner, not in the calibre.