Just an observation;
The BoJ's Pres. Ueda is not entirely wrong when said (over the weekend) that "inflation in not a factor in the BoJ's policy guidance.". Not necessarily because that statement in itself is true but rather because even a quick a back-of-the-envelop calculation shows that any "policy adjustment" - i.e., rate hike - here would "un-invert" US & EU yield curves, prompting a massive Gov. securities dump, world wide.
And since there must be a buyer for every seller ... A (very) conservative estimate in such a move would cost Japan $600-$800 Billion, on day one! (Very, very conservatively. A more precise estimate would put this number well in excess of $1 Trillion.) So, a Cost/Benefit analysis, under the present circumstances, makes such a move questionable - arguably Neutral - when global rates are sitting smack in the middle of even the widest, reasonably predicted rate range (0.5-7.5%), going forward.