Forget one rare Patek Philippe – three siblings are going under the hammer this autumn

Rare Patek Philippe watches, it seems, are rather like buses – you wait all your life for one to come along, and then three turn up at once. Just a few weeks ago, we reported on the news of a holy grail-grade Patek Philippe ref. 1518 in steel, which would be going under the hammer in November.

The model is one of just four steel examples known to exist, making it the absolute pinnacle of watch collecting for many. This one has an even more storied history – it was the first of the four to be produced, and broke a slew of records when it was auctioned back in 2016.

It's not going to be alone, though. The model will be showcased alongside two other 1518 references, including a pink-on-pink example, which fuses a pink gold case with a salmon-toned dial. That's about the next step on the rarity scale – just 15 examples of that combination are known to exist.

Rounding out the set is the most commonly found example – the yellow gold. That's still not the sort of watch you'd spot on a quick trip to the shops – only 281 examples were ever made across all case and dial variants – but it's certainly the one most people will think of when they imagine the 1518.

Having these three pieces together at one auction will make it a must visit for serious watch collectors. While the November 2016 auction – which saw the steel 1518 break several records – had all three different case materials at one show, but didn't have the elusive pink-on-pink variant.

The Decade One auction will mark the first time those three versions of the iconic timepiece have been under auction at the same show.

There's quite some variation in the estimated pricing for the three models, too. The yellow gold example is the most affordable, with a guide range of CHF 200,000 - 400,000 (approx. £278,000 / €321,500 / US$380,000 / AU$568,500).

Next up is the pink-on-pink example, which is estimated to fetch between CHF 1,200,000 and CHF 2,400,000 (approx. £1.65m / €1.95m / US$2.27m / AU$3.4m). But the headlines are almost certainly reserved for the steel model, which is estimated to sell between CHF 8,000,000 and 16,000,000 (approx. £11.1m / €12.9m / US$15.2m / AU$22.8m).

Whatever happens, it's certain to be a landmark moment for the watch industry and collectors of vintage pieces.