Japanese 10-year bonds yield about 0.76%. The new Japanese government has told its central bank to print money until they reach an inflation rate of 2%. That means anyone holding those bonds will be losing money as the interest rate will be less than inflation. It also assumes that the Japanese Central Bank can target an inflation rate and not overshoot it.
There is a positively enormous amount of Japanese debt out there.
Good thing we're not primed for the same thing here.