The UNODC cited a number of theories for why homicides occurred so rarely in Japan, including the fact that 98 percent of homicide cases are solved, the growth of affluence and a general rejection of violence after World War II — even the country's organized criminals, the yakuza, are said to avoid violent confrontations, coming up with unusual techniques such as standing outside a business swinging a cat by its tail to extort money.
Of particular interest to American readers might be the scarcity of guns in Japan. The country has strict requirements for owning a gun and harsh punishments for those who break the rules. As a consequence, there are few guns in the country; Japan has 0.6 guns per 100 civilians compared with 101 guns per 100 civilians in the United States, and even firearm enthusiasts seem comfortable with that. Japan had a single shooting death in 2015, compared with more than 13,000 in the United States. According to one count, 475 people were killed in mass shootings alone in the United States last year.