Bank of Japan recently announced quantitative easing. Their economy is so dire, when they announced an inflation target of 1% (!!!) it meant huge QE to get there.
Hence the yen pairs have taken off lately. Not just USDJPY. (taken off = other currency up, JPY down of course)
Also threat of intervention from bank of J meant that selling UJ was a bit risky recently.
80 is the ultimate target for UJ and it will be very interesting to see what happens later on tonight, now that it has been hit.
