For starters, there was never a lot of guns in the hands of civilians in Japan so it shouldn't be that hard to keep them banned. It's also risky to bring guns

For starters, there was never a lot of guns in the hands of civilians in Japan so it shouldn't be that hard to keep them banned. It's also risky to bring guns illegally into the country; to take that kind of risky one would probably have to be into other illegal, profitable stuff like drug trade. But there isn't a lot of drug trade in Japan (compared to US). Anyway, I think it's very hard to use Japan on one hand, or Switzerland and Israel on the other, to argue about gun laws in US.