SIGNED PATEK PHILIPPE, REF. 5231J-001, MOVEMENT NO. 7'387'692, CASE NO. 6'437'977, CIRCA 2021

Introduced at Baselworld 2019, the reference 5231J displays subtle changes to the design of the case, dial and hands and an incredible cloisonné enamel and gold pailloné dial centre decorated with a planisphere representing the American, European and African continents surrounded by the names of 24 world locations. Only two or three of the very best artists in enamel are able to produce these rare dials and together they can only deliver a maximum of 30-40 every year. Powering the World Time 5231J is the automatic in-house calibre 240 HU composed of 239 parts and 33 jewels. The calibre provides a power reserve of 48 hours when fully wound and is visible via the display case back.

To operate the world time mechanism for a different time zone, the pusher on the caseband at 10 o'clock is pressed as often as needed to align the respective city name with the red arrow at 12 o'clock. Each time the pusher is pressed, the hour hand advances by one hour while the city disk and the 24-hour ring will move by one increment in the anti-clockwise direction.

Although a very modern world time wristwatch, the world time system used here dates back to the 1930s when talented Geneva watchmaker Louis Cottier devised it and offered his invention to Patek Philippe. Cottier's ingenuity resulted in the company's now classic vintage references 1415 HU and 2523. In 1959, Patek Philippe obtained a patent for Cottier's device (Swiss Patent No. 340 191). The company further developed the movement, introducing calibre 240 HU found in the present watch in 1999.