70s Steel Jumbo Watches: Black Dial Collection

The Patek Philippe World Time reference 2523, launched in 1953, is distinguished by its innovative two-crown system. One crown serves for winding the watch, while the second, positioned at 9 o’clock, controls the city disc. This design marked a significant development in the functionality and user experience of world time complications for the brand.

The reference 2523 was offered in two primary versions. The initial ref. 2523 featured larger lugs that extended above the bezel, with a case diameter of 35.5 mm. A subsequent variant, ref. 2523/1, presented a slightly larger diameter of 36 mm and thinner lugs that were integrated without extending above the bezel. Both versions were powered by the caliber 12-400 HU, which incorporated the world time module developed by Louis Cottier.

This reference appeals to collectors interested in Patek Philippe's historical advancements in complicated watchmaking, particularly the evolution of its World Time series. The distinct design differences between the 2523 and 2523/1, especially regarding lug integration and case dimensions, provide specific points of interest for enthusiasts tracking the model's development and variations.

The Royal Oak reference 5402 is recognized as the original iteration of the model, introduced in 1972. This reference established the design language that would define the Royal Oak collection, characterized by its integrated bracelet and octagonal bezel secured by visible screws. It was initially presented as a luxury sport watch, distinguishing itself through its material and finishing in a period dominated by more traditional dress watch aesthetics. The 5402 was produced in various series, with the A-series being the earliest and most sought after by collectors.

The watch features a 39mm stainless steel case, often referred to as the "Jumbo" size, which was considered substantial for its era. It houses the self-winding Caliber 2121, a thin movement derived from Jaeger-LeCoultre's Caliber 920, known for its full-rotor design. The movement provides a power reserve of approximately 40 hours. The crystal protecting the dial is acrylic, and the watch offers a water resistance of 50 meters, suitable for general wear.

For collectors, the reference 5402 holds significance as the foundational model of a major watch series. Its various production series (A, B, C, D) present nuances in dial text and case back engravings that are closely examined. The integrated steel bracelet is an integral part of its design, contributing to its distinct profile. The blue dial, often with a "tapisserie" pattern, is a hallmark of this early reference, though other dial variations exist.

The Audemars Piguet Royal Oak reference 5402ST is identified within the Royal Oak series. This reference is part of the Royal Oak "Jumbo" models.

The case material is steel. No further details regarding the case, crystal, or movement are provided.

This reference appeals to collectors interested in the Royal Oak "Jumbo" series. It is a specific iteration within the broader Royal Oak collection.