Japan has a very low crime rate. You might not believe but Japan records only two to three homicides per year on an average. It is in fact one of the lowest crime rate countries in the world according to the UN. On average, fewer than three people get hurt due to violence of any kind in every million in Japan. Japan recorded only 11 homicides in 2008 while the rest of the globe recorded 12000 on average in the same year. The main reason for Japan being the lowest homicide country is due to its lowest inequality and a stable and prosperous economy. This was not the same scenario before the 50`s when Japan was underdeveloped and devastated due to the wars and other reasons. Japan is certainly a role model in this aspect. Japan has very strict weapon regulations and gun laws. Carrying a weapon in Japan is considered illegal. One cannot carry a sword in Japan too. Japanese police force is one of the swiftest and the crime solving rate is higher than in any other country. The point here is crime happens everywhere but in Japan, the number is certainly very low.
Japan is a collectivist society with rich family values and traditions. If someone does a bad thing, it is seen as a shame on their family name and ancestors. Also, most of the Japanese people are taught to be polite from childhood. Japan is largely safe and many Japanese people tend to feel guilty in case of any mistake. Albeit one can find some petty crimes on newspapers, severe crimes are rare in Japan for sure. Moreover, if you lose your purse or anything, there are more chances that it finds you well. The Lost and Found offices are there in every train station and Koban Police points are in nook and every corner of the city.