In 1986, Patek Philippe introduced reference 3970 alongside the rarer reference 3971. The 3971 carried very similar features as the 3970, though with a sapphire case back whereas the early 3970’s were fitted with a solid case back. The reference 3970 was the firm’s signature flagship model which was discontinued in 2004 and replaced by the last reference to be fitted with a Lemania based ébauche. The ref 3971 from 1986 until 1988 was first offered with a snap-on back, also known as the first series with approximately only 100 pieces made. Similar to the present example, the second series began production from 1987 until 1990, known as the ref. 3971E (E for "étanche" or "water-resistant") and was equipped with a screw-down case back with only 170 pieces made according to research.

The present example in yellow gold fitted with an attractive silvered dial with English day and date indication is preserved in an absolutely delightful condition. Boasting a strong case with defined stepped lugs, the hallmarks on all four lugs remains perfectly intact including the Patek Philippe case maker stamp—number 28 key for Atelier Réunis. Extremely elegant, the yellow gold case has also developed a warm patina and an immaculate dial featuring feuille hands and rectangular markers from the earlier series. Furthermore, the present lot is accompanied by its original Certificate of Origin and accessories, as well as the Patek Philippe Extract from the Archives confirming the timepiece from 1990. Highly sought after and equally collectable, this present example is not one to miss for perpetual calendar chronograph connoisseurs.