Why was the culling begun?
The reason for this was that rabies became epidemic in Japan.
Rabies is a very dangerous infectious disease with a mortality rate of 99.9%
It is said that rabies came into Japan during the Edo period.
From there, it became popular once in a few years, and it has gotten overwhelmed, the current case of infection is a returnee from overseas.
When the Japanese government was forced to take measures, in 1922 he enacted the Lawful Arm Society Law Prevention Law. The content of this law is that you catch wild dogs and you can kill them if they do not offer from the owner within three days.
This is the beginning of the culling in Japan that continues until now.