Continuing my quest for the perfect Patek Philippe Calatrava, I turn to the other main branch of the family. In 1973, Patek Philippe added “Clous de Paris” guilloche to the bezel of a straight-lug Calatrava and a new legend was born. Today, many people think of this Ref. 3520 rather than the clean, flowing original when they hear the name! Is this the perfect Calatrava?