The reference 3970 was the first Patek Philippe perpetual calendar chronograph to indicate leap years, and the first to add a 24-hour indicator. Unusually, and despite the more complex mechanism within, the reference 3970 represented the first drop in size in the perpetual calendar chronograph family, from 37.5mm down to 36mm.

The reference was divided into four series: the first series featured a snap on caseback, with applied gold sword indexes and feuille hands. The second series featured a screw-down, solid caseback, with the hallmarks stamped on the outside of the lugs. The third series featured a sapphire display back along with a screw-down solid caseback, like the present example. The fourth series is identical to the 3rd series, but the movement numbering system changed.

Made in yellow, pink and white gold as well as in platinum, the present example is a highly rare example of a white gold variant fitted with a black dial with applied white gold hour markers. Most 3970s in white gold were originally born with silver, or “argenté”, dials. Fresh to the market, and with the coveted black dial confirmed on the original Certificate of Origin, only eleven examples of this combination of 3970 have appeared on the market. The slight warmth of the white gold case paired with the sleek, inky black dial is an irresistible combination, only made more desirable by the phenomenal condition of the case, with its perfectly preserved hallmarks and sharp fluting to the lugs.