Ask the average watch guy what the ultimate combination of complications is, without crossing into the realm of obscene, and odds are he’ll say “the A. Lange & Söhne 1815 Rattrapante Perpetual Calendar with split-seconds chronograph.” More accurately, ask ME what the ultimate combination of complications is (for a mega daily wearer), and I would say “the perpetual calendar with split-seconds chronograph.” Sure, there are more complicated, technically impressive watches out there – the repeaters, the tourbillons, and such, but at a certain point, it just becomes A LOT. For me, I’m not sure I would even want to wear a watch more complicated than a rattrapante QP – but that’s another story for another day.

Up until last week, there was really only one reasonable choice when it came to split-seconds perpetuals – the Patek Philippe reference 5004, or more recently, the reference 5204 introduced this past Basel World   (yes, others have done it, but few famously or elegantly). At SIHH this year, A. Lange & Söhne 1815 Rattrapante Perpetual Calendar introduced the watch you see here, the 1815 Rattrapante Perpetual Calendar, and hit Patek right where it hurts. Here’s why: The new 1815 Rattrapante Perpetual Calendar is an incredibly traditional watch – like something you might expect from Patek Philippe. So, where with hard-core Patek fans, the Datograph, with its outsized date and luminous hands, might be a little too funky, the 1815 line with traditional QP date display and blued steel hands can not be criticized as such. And the new 1815 Rattrapante Perpetual Calendar has a beautiful new movement – caliber L101.1 – complete with 636 individual parts. The split-seconds mechanism has two individual column-wheels – one for the chronograph and one for the rattrapante – and just like on the existing Lange Double-Split, the rattrapante is activated by the button at 10 o’clock. (Sidenote – if Lange really wanted to play this game, they should’ve put the rattrapante in the crown – some would argue placing the rattrapante at 10 o’clock is a bit of an “easy way out,” and the only other watch to do so is IWC’s Valjoux 7750-based rattrapante – not exactly the same thing).

Still, the Lange caliber, visible through sapphire caseback, is gorgeous, though it doesn’t have the same depth as found in the Double-Split, or even the Datograph for some reason. But, I wouldn’t kick it out of bed, let’s just say that.

The A. Lange & Söhne 1815 Rattrapante Perpetual Calendar mechanism consists of 200 of the 636 components and will not need to be reset until the year 2100 – when the traditional leap year schedule is thrown off and the calendar will need to be advanced by one day – done by the push of one button.

Also, something that Lange has been criticized for in the past in the general beefiness of it cases.  The Datograph sits high on the wrist and the new Grand Complication is over 20mm thick, so if I had to guess going into the presentation of the 1815 Rattrapante Perpetual, I would’ve bet the farm that it too would be just a little too thick.  I would’ve been wrong.  Because, it’s only 14.7mm thick.  Yes, that’s large compared to most watches, but this is a REALLY complicated watch, and it chief rival, the Patek 5204, clocks in at 14.19mm thick, so we’re talking a negligible difference.  Also, the Lange is 41.9mm in diameter, while the 5204 is 40mm.  Which wears more balanced is hard to say without spending real time with both of them.   So that’s all we’re going to cover for now – you can read more about the A. Lange & Söhne 1815 Rattrapante Perpetual Calendar here.  But, don’t think we’re done with this conversation for a minute – because we ain’t.  This is too good of a side-by-side to let it die here….stay tuned.