Notes: Rolex Dato-Compax Calendar Chronograph, ref.6036. 18kt yellow gold.

Mechanism: The 72–is a classical, manual winding, column wheel, lateral clutch chrono. Today, watchies get all excited about column wheels and vertical clutches, but there’s very little wrong with a lateral clutch. In fact, it’s rather simpler to service. A lot of vertical clutches don’t ever get taken apart so, like 1970s Fords, simply die of old age and neglect.

The 72’s most famous outing was as the engine that powered the Rolex Daytona for nearly 30 years. People often think the Daytona ran either Zenith or Rolex movements, depending on the age of the watch. In fact, the manual 72–first renamed the Rolex 722-1, then the Rolex 727–powered the Daytona from 1961 and the ref. 6239 right the way through to 1988 and the ref. 16520. That’s when it gave way to the automatic 4030 (a Zenith 400 in a Rolex party frock). So that $1.1m Paul Newman you’re lusting after? It’s a humble Val. 72 inside. Admittedly it’s been tweaked a bit with a Breguet hairspring and a Microstella balance, but it’s a Val at heart.