A Second Series 3970 in platinum, the singular known example combining an Italian calendar with the desirable Big Hallmark. Just 11 Second Series examples were produced in platinum, the rarest standard production metal, only two in Italian. The rarity of this configuration is matched by that of its condition, its case and dial unrestored and exceptional. The 3970 succeeded the 2499 in 1986, the most significant contribution of Philippe Stern’s tenure over the brand. It features a 36mm Ateliers Réunis case, Lemania ébauche calibre CH 27-70 Q, feuille hands of Early Series, ‘American Typewriter’ font, and warmer Argenté dial of Early Series. It is the Perpetual Calendar Chronograph that did more with less; despite a smaller size and greater degree of information displayed than the 2499 that preceded it, the 3970 succeeded in making immense complication not just easily understood, but beautiful. Worth Reading: Exclusives, live. This is the only known platinum Second Series ref. 3970 with Italian date discs and a “Big Hallmark.” Just 11 platinum Second Series examples are known, only 2 with an Italian calendar. The Perpetual Calendar Chronograph is Patek Philippe’s most lionized complication, long synonymous with the brand. Introduced in 1986 as successor to the 2499, the 3970 reflects clarity, restraint, and traditional watchmaking at its highest level—widely considered one of the most important models of Philippe Stern’s era. The PCC originated in 1941 with the ref. 1518, the world’s first serially produced perpetual calendar chronograph wristwatch, created by Charles and Jean Stern. No other brand attempted the complication in a wristwatch for over 50 years. The 3970 emerged during the mechanical revival after the quartz crisis, embodying a more disciplined design than the 2499. Its 36mm case strikes a balance between earlier and later references, with refined concave lugs and bezel details. The dial is highly efficient, introducing stacked subdial hands, a leap year indicator at 3, and 24-hour display at 9, while preserving the classic twin apertures at 12. The Argenté dial has a subtle grained finish. First introduced in yellow gold in 1986 (fewer than 100 pieces), the Second Series added other metals and a screw-down caseback. Fewer than 650 Second Series examples were made: most in yellow gold, ~60 in pink gold, ~15 in white gold, and just 11 in platinum. The “Big Hallmark,” briefly placed on the lug exterior, is a rare and desirable variation. Even compared to First Series, this example is the rarest standard production 3970 metal and series with the added allure of Big Hallmarks. First and Second Series are distinguished by feuille hands and “American Typewriter” font dials, with warmer Argenté tones than later series. Inside, the CH 27-70Q—based on a Lemania ébauche—was heavily reworked and finished by Patek to Geneva Seal standards. Combining rarity, historical importance, and exceptional preservation, this example with Italian calendar and Big Hallmark is an incredibly desirable variant of one of the most important references in Patek’s history. Condition: The condition of this example is remarkable. It is one of the best-preserved examples of the 3970 Second Series in platinum currently known. The case is in our opinion unpolished. The lug profile is sharply defined, full, and appears true to original. The bezel has no rounding, and the big hallmarks are sharp and deep. The dial shows no signs of damage or intervention, with light patina creating a soft eggshell tone. There is some oxidation on the hour hand and the chronograph seconds hand, as is common for 3970 examples. Sale includes the original box (with setting pin), original leather folio, extract showing 1990 production date, manual, history of Patek Philippe pamphlet. Specifications: This example is modelled on an average-sized 7-inch wrist. Brand: Patek Philippe Model: Perpetual Calendar Chronograph Reference: 3970EP Size: 36 Year: 1990 Case Material: Platinum Movement: Manual Calibre CH 27-70 Q Scope: Watch, Box, Extract, Pusher Tool