A true classic can also be recognized from its large number of admirers. By popular request: the Da Vinci Perpetual Calendar Edition Kurt Klaus – in red gold 5N with a black dial. For more than twenty years, the Da Vinci in a round case with the perpetual calendar developed by Kurt Klaus was the iconic IWC watch. The Da Vinci made its debut as a chronograph in conjunction with the transition to the distinctive tonneau shaped case.