Followup - - -
I checked with the wife this morning and the world traveler says she did not have it when she left the US back in March. She also said she did not buy anything here in the US with cash when she got back stateside on Saturday.
So, thinks she probably got the note at a foreign exchange or bank in Japan before she left. It is still crisp new with no folds. It's now in a currency sleeve and added to my "ten" collection!