But why would one single country tamper with their own reports - that is, what would motivate Japan, more than other countries, to tamper with their reports? L

But why would one single country tamper with their own reports - that is, what would motivate Japan, more than other countries, to tamper with their reports? Like I see the argument for why all countries would want to make themselves look good. (It's weak, because if people start dying in ways they're not tracking they have bigger problems, but I can see the argument that the motivation exists.) And I can perhaps see the argument that the more autocratic a country is, the more likely they are to do so. But none of that explains the observation "Japan is reporting a low number of covid cases compared to other similar countries" - and especially not "Japan is reporting a sudden drop in covid cases compared to other similar countries." You need to multiply a lot more entities to get there.