This is why.

I was going over the Norton last night, checking assorted fasteners and such, when I remembered something from last year.

This is why you check your motorcycle before you go on a trip. Good job I had done just that before that weekend away back in August when I went to meet the boys on their way back from the Alps; look what I had found when checking the chain!

This was supposed to be a heavy duty, superior quality Regina Serie Oro chain... I wonder what happened here, perhaps a stone or other piece of road debris?
Not only had a section of link vanished, but the master link also cracked so that one of the pins was held on only by the circlip.

It could have ended rather badly, but then again I couldn't tell you when this actually happened nor how long I had been riding like this. Hundreds of miles? Thousands of miles?
I know the Commando just chews through chains, it shreds them actually, but this is new even to me, and I've replaced my fair share of chains on this bike.
Bear in mind that I had discovered this in mid-August last year, a time when Rome is typically shut down. For a moment I thought I would have had to forego the trip on the Commando and take my poor Sportster instead, but I went to see a generic spares supplier in the area (the same one where I got the new battery) and against all odds they were open! I got a replacement chain and quickly fitted it. Child's play if you have a grinder (I guess I must have done it right because it hasn't given me any problems since).

I don't think I'd ever get around to doing this, but I wonder if a belt drive conversion wouldn't be a bad idea...