I made money on the elevator ride to 100 (it should have been more, but then it always should have been more) and I am out of this pair for now.
My own analysis of the way the yen's real effective exchange rate has evolved recently suggests to me that the ride is over and I am reading enough similar opinions elsewhere to believe that the trend is no longer easy to call.
I don't know what you call "fundamentals". You refer to "US bond yield's .. rising" and the view that "BOJ with Kuroda and Abe must prove to the world that they can ... walk the walk". Are those fundamentals? I wish you good luck with them.
PK