Another rare Patek Philippe watch is going under the hammer – and it's just weeks away

At the tail end of last year, we saw three incredibly rare Patek Philippe 1518 models go under the hammer in Switzerland. That included the steel 1518, which is one of just four known to exist, making it one of the rarest watches out there.

Still, never to be outdone, there's another Patek Philippe going under the hammer this May – and it's even more rare than that. The Patek Philippe Ref. 2523 is a two-crown world timer watch, complete with an enamel dial depicting a map of South America.

It was crafted all the way back in 1953, and is one of just two examples known to exist in the 18k yellow gold case. This particular example is also the only one to have previously appeared at auction, all the way back in 1988 in New York.

Interestingly, though the watch was produced in 1953, it wasn't actually sold until February of 1958. I can't see there being any such wait for it this time though, with the model representing one of the absolute top tiers of watch collecting.

The wider 2523 collection is believed to exist in between 29 and 36 pieces, with the enamel dials being the most popular and desirable. There are three map designs known – Eurasia, North America and South America – and the South American dial is believed to be the rarest.

The piece sits within a 36mm yellow gold case – a size considered large for the time – and features a pair of crowns, with one on either side of the case. The second crown is placed at nine o'clock, and allows for the independent rotation of the city ring dial, while the three o'clock crown can continue to amend the time as you'd expect.

So, just what is a watch like this worth? Well, that's quite hard to say, given its rarity, but auctioneers are estimating it to break the CHF 5,000,000 (approx. £4,775,000 / €5,533,000 / US$6,370,000 / AU$9,000,000). That feels on the low side to me – the aforementioned steel Patek Philippe 1518 sold for just over CHF 14,000,000, and there are quite literally twice as many of them.

If I had to wager a guess, I think this one could land somewhere in the CHF 10,000,000 range, and in vintage Patek collecting circles, that could be seen as a bit of a bargain.