Valjoux 72C

Triple calendar version of the Valjoux 72 column-wheel chronograph, introduced in 1946. Features day window at 11:30, month window at 12:30, and central date hand, in addition to full chronograph functionality. Only approximately 1,300 examples were produced (far fewer than the Cal. 88 with moonphase). Calendar functions adjusted via inset pushers at 8:30 (date) and 10:00 (day/month). Used by Rolex in the 'Jean-Claude Killy' triple-calendar chronograph, as well as Girard-Perregaux, Zodiac, and Gallet. Replaced by Cal. 730 in the 1970s.