Can’t exactly say why other than perhaps some USD index-related buying. Given that the latest swoon in EUR/USD felt like margin-related buying, it is possible we are seeing similar buying in USD/JPY. With all the ETFs and other products out there today it is getting harder and harder to tell what is moving what..
USD/JPY is up near 8060 from afternoon lows in the 80.20s on EUR/JPY selling.