It has been a good run for the pair since the beginning of last week but it seems like the upside momentum is running out of steam now. As Treasury yields hit a bit of a wall, we are also seeing USD/JPY drop off a little today. The pair is down 0.3% today to 145.37 currently.
On top of the bond market developments, there is also the fact that between here and the 150.00 mark, we're pretty much in intervention territory by Japanese officials. That also subtracts from the more bullish appetite and you can imagine that if there are any signals to let go, then buyers would be more than willing to after the run since the middle of last month.
It's tough to pick at technical levels at the top especially when central bank intervention sentiment is involved. It can be very subjective.
In any case, the more straightforward technical picture dictates that if we do see a drop back below 145.00, that should invalidate the latest break higher until buyers can find a footing again.