> and the only effect will be to devalue the yen, if anyone cares, which they don't.
So if the yen is devalued to $0.0000001 they won't care? With what will they pay for imported oil? Japan might prefer a weaker currency; not worthless, but stable. Many japanese entities have foreign denominated debts, and exporters also rely on imports in some form.
> Everyone knows it's unpayable, if it had to actually be repaid, which it doesn't.
The national debt of any country is not expected to be repaid. Japan is no different. Nor is the Japan the only country writing a bunch of cheques to itself. That's the essence of QE.
Japan is heavily in debt. Were they to write off that debt overnight, it would still be heavily in debt because the write-off would show up in the accounts of the bond-holders, many of whom would be made insolvent. Foreign entities would then refuse to trade with Japan. You'd merely be taking from one hand and giving to the other. There's no trickery or matrices, there's nothing unreal about any of this. The accounting practices may be absurd, but there is real value at stake, and destroying it is to be avoided, not posed as a solution.