Growth has been steady in Japan for a while now and the Bank of Japan is expected to start raising rates. Ten year bonds yield around 1.60% these days. Two year paper yields around 0.48%. Both numbers reveal an economy that has not been well for a long time. If it really is turning around for Japan, the world's second largest economy, it makes sense to believe there will be some dislocations.
Over the last few years, money has flowed from yen in to dollars in search of yield. Japan owns more than $800 billion worth of US debt (that number as of last fall). It is unlikely that Japan would sell what they own, but the buying may slow down. If yields in Japan do go up it makes sense to expect capital from other countries to flow into Japan for diversification from US holdings.
This could lead to rates having to go higher in the US to attract investor interest. None of this bodes well for the US. I'm not sure it will be dire but it may not be as cheap to borrow money and growth may have to slow.
I have been making a case for more demand for euros due to shifting petro dollars and the potential for trading commodities in euros instead of dollars. Now factor in yen resurgence.
This more of a multi year call than a six month call.