To follow up on my post at the top - I didn't check bags. I was told when I got off the plane in KIX that I would need to collect my luggage and take it with me to the other terminal. It's not clear (a) whether I would have been charged to re-check or (b) whether it would be different in a different airport. My impression is I would have had to collect in NRT as well. I don't know about a transfer in ICN.