Originally Posted by Dark Blue

I was just guessing. But I often got upgraded with both JAL and ANA as OWE (BA Gold) and NH Diamond, probably like 10-15 years ago (I also regularly received such domestic upgrades from DL when I had AF Plat). My flights seem quite empty, I just thought I would be upgraded from the past experiences. But yes, this is sort of a TP run, I thought it's worth paying the extra 4,000 JPY to get more TPs.

I don't take any domestic flights in Japan anymore, normally LHR-TYO only. Once such an airport upgrade offered at check in, PE to J for £500 or something.