USD/JPY has been on a tear since the beginning of the month in large part due to rising U.S. yields. Based on the following chart, the slope of the recent rally in USD/JPY is much steeper than the slope of the 2 year U.S. Treasury yield which suggests that either the run in USD/JPY is overdone or U.S. yields need to rise further - you decide.
JPMorgan is trying to compare this to Dec 2009, which I have circled in the chart:
There have only been two instances since the Fed started its zero interest rate policy, when the USD was strong at the cost of the JPY – February 2009 and December 2009. Particularly, the latter month saw a risk rally, which is a better resemblance of the current situation. USD/JPY rallied about 10.5% in December 2009. If we see a rally of the same magnitude this time around, the pair could reach 84. That being said, we still believe USD (and hence USD/JPY) upside is limited unless we see a sharp rise in UST yields