Hmmmm. Japan??

Mish ain't an optimist about Japan.

...rolling over US debt is unlikely to be a problem. The same cannot be said for Japan. Because of demographics, pension plans will be net sellers of Japanese bonds. Unless balance of trade or tax revenues increase enough in 2012 Japan will not be able to roll this debt over at 1%. A rise to 3% would consume nearly all of Japanese revenues.

Japan's total debt is ~$3.0 trillion, even larger than that of the US (~$2.8Tn).

Demographics is destiny.  Japan's population is aging fast and will be decreasing, partly due to the culture, and partly due to xenophobia.