‘Graph Paper’ 3505 IWC Ingenieur SL

Graph paper isn’t the sexiest thing in the world. And, yet, put it on an IWC dial as texture and it just might be. One of the best parts about this mid-sized Ingenieur from the early 80s is that there are multiple generations that each have equally attractive personalities. Are you a COSC kind of person? Go with the JLC-calibre 3521. Do you want all-out technical a-mag innovation? 3508? Or, do you want the first of the breed, with a characterful dial that’s beautiful and not seen in any other generation (just 3505 and 3506). That’s what this is. It’s the 3505, with the desirable graph paper dial, a Swiss-only signature, and 4mm thin calibre 375. It’s estimated that considerably fewer than 800 3505s were made, and they’re perfectly positioned to get your inner engineer hot under the collar.

That calibre 375 was modified ETA 2892 base. Shortly after release, ETA debuted the new and smaller 2892-2, which led IWC to redesign a few details. Reference numbers and a few details changed over as well, leading this first mid-sized Ingy to be also one of the smallest in overall production. It’s not a vast difference to the latter 3506, but the first of anything has a way of becoming collectible all its own. It’s still water resistant to 12 ATM, a-mag to 40000 A/m, and Germanic in design. Millimeter paper, I should be saying. Perhaps the 3505 is mostly remembered as blazing the path for the highly technical 3508, which does tend to steal headlines; it’s a bit like the earliest ETA Black Bays to the 58s which came later. But like the ETA Black Bay, it’s a very lovable, significant, and attractive reference in its own right worth underscoring here.

IWC’s re-release of the Genta jumbo SL has seen quite a bit of attention shone on the vintage or neo more alternative Ingenieurs in the last year or so. For example, friend of Hairspring @siemswatches put together an excellent guide and bit of scholarship cataloguing all early references and their story. This Genta cased Ingy is well over a 10/10 on the value scale today. It’s why I can’t stay away from frequently calling them out. I have the sneaking fear that they might not stay this way, we only appreciate the golden years after they’ve gone. Anyways, if anything can make engineering be sexy it’s the millimeter paper dial IWCs.


As examples go, this one is also a knock out. It’s the subtler white dial, fantastic case, and sharp edges with the original (correct to be) not-aligned bezel. Moreover, it comes with its full set including both the original certificate and an extract. That’s something we never see. A very lovely watch that doesn’t break the bank, we need more of those. This one comes from a well-regarded Swedish retailer.