Patek Philippe, Reference 5970 The Ref. 5970 ?? a writs-chronograph with perpetual calendar ?? represents a “Must” in the production of the Genève manufacture. This model is the heir to an impressive series of watches that have wrought ?? if need be! ?? the reputation of the brand among collectors. It all started in the 1940’s with the launch of Ref. 1518 (1940-1951), which will be followed in the 1950’s by Ref. 2499 (1949-1987), then in the 1980’s by the Ref. 3970 (1987-2004). If these models are now highly coveted by amateurs, it is due to the fact that after the Second World War, Patek Philippe was the only watchmaker in the world to be able to produce in series this kind of parts, certainly in a few examples each year but of a remarkable quality of execution. The Ref. 5970 was launched in 2004 and will be produced until 2011. It remains today a very popular model among collectors, not only because its classic line is timeless but also because it incorporates the latest movements of manual-winding chronograph made by the manufacture (based on a highly improved Lémania calibre) ?? the Cal. CH 27-70 Q ??, before Patek Philippe presents his own movement used for his new Ref. 5270.