As you know, Japan was defeated in World War II.
As a result, a new constitution was created so as to limit the power of the state.
It has war-renouncing Article 9, and does not have an emergency clause on responses to large-scale disasters.
Therefore, the Japanese government is unable to restrict the person's rights in any cases even in this ongoing pandemic of the novel coronavirus disease.
Indeed, an emergency was declared in Japan, but it did not introduce any penal regulations.
Partly because of the deplorable housing conditions in the inner city, some people are tired of staying home and crowded into the downtown area.
Idiots?
Maybe.
The only thing I can say for a fact is that Japan is a weird country under an odd supreme law.