Patek Philippe’s reference 3940 was released in 1985 as a replacement to the reference 3450 with a newly designed modern case, which was less angular than its predecessors. Powered by the all-new, ultra-thin caliber 240, Patek Philippe’s first movement to use a micro-rotor, it enabled an elegant and very thin case that fit tightly to the wrist. In production for over two decades, the reference 3940 was a smashing success, and appealed to a new generation of enthusiasts who wanted to advance beyond their fathers’ timepieces.

The wristwatch was encased predominately in yellow gold, with fewer examples in pink and white gold, and very rarely in platinum. In 1985, the first 25 watches were produced to celebrate the 225th anniversary of the famed retailer Chronometrie Beyer in Zürich with numbered watches. That same year, the brand began standard production of the reference and continued to produce it until 2007 when they replaced the 3940 with the reference 5140 powered by the same caliber 240 movement, but with a case measuring 37mm in diameter.

The present watch from 1987 is part of the first series of the reference 3940, which was produced only during the first three years. These early watches featured flat, sunken subsidiary dials giving them a pleasing vintage look, and a single leap year indicator compared with later models having a cross dividing the four sectors. With its visible hallmarks to the side of the case, this particular 3940 offers an excellent opportunity to own a coveted, “first series” version of a classic perpetual calendar timepiece.