With the price level falling and the population aging, the Japanese consider the real return attractive. As long as US banks can borrow at near zero and buy government bonds without having to commit equity, and the dollar does not depreciate against the renminbi, interest rates on US government bonds may well be heading in the same direction.
日本利率如此低下的真实原因是日本私人部门不愿意出国投资，而十年期国债的收益率（1%）也要好过持有现金（零收益）。日本的物价在不断下降，人口在日益老化，这使得日本人觉得真实回报率相当可观。只要美国的银行能够以接近零利率借款并买入美国国债而不是增发股本，而美元又能不对人民币贬值，美国国债利率也将像日本那样维持在很低的水平。