Kurt Klaus is the IWC watchmaker best known for the brand's user-friendly perpetual calendar. He joined IWC in Schaffhausen in 1957 and trained under its technical director Albert Pellaton, whose automatic winding system still bears his name.
In 1985 he presented his best-known invention at the Basel fair: the Da Vinci Perpetual Calendar Chronograph, in a round gold case, the most complicated wristwatch IWC had made to that date. Klaus designed and laid out the whole mechanism with a slide rule, pencil, paper and paper models, and it was the last IWC movement designed by hand before computer-aided design took over. It was the first perpetual calendar in which all the indications, day, date, month, four-digit year and moon phase, were coordinated internally and could be set from the crown, without the pushers that earlier perpetual calendars needed. It was also the first perpetual calendar wristwatch to show the year in four digits, and its moon phase was accurate to one day in 144 years. The module was paired with the Valjoux 7750 chronograph and later with other base movements. The final display discs were finished only the day before the show, and Klaus drove from Schaffhausen to the supplier in Grenchen to collect them, fitting them into the first three prototypes himself half an hour before the doors opened.
His perpetual calendar became a signature of IWC's complications. When the Da Vinci moved to a tonneau case in 2007, IWC marked the end of the original round model with a final Perpetual Calendar Edition Kurt Klaus, in platinum, red gold and finally, after strong demand, 3,000 pieces in steel.
Sources are thin on his own life; Casadi has not verified his date of birth or when he retired.