A bit off topic but I feel a need to clarify after reading some of the posts above.
Japan?
Sure you're not thinking of China (Hong Kong)?
Chine (mainland) & Hong Kong (island) has much higher crime rates compared to Japan. Hong Kong, during its colonial days, was like the Sicily of the East.
Japan also has one of the most violent, sexually explicit comics industries in the world, and yet their people are polite and restrained to (in American eyes) an absurd degree.
Two reasons behind this (IMHO):
1) A lot of that is for show to the outsiders. Orientals (especially the Japanese) are extremely concerned about 'saving face' (not being embarrasses) in front of foreigners. They will cover up ANYTHING to give a good front. Of all the crimes committed in Japan, a lot are not even reported due to fear of bringing shame and dishonour to the family, and then another good proportion are settled outside of the system, so as not to shame the government and the country.
FACT: The Japanese government rewrote their history books to cover up atrocities committed during the 2nd world war, resulting in a whole generation of disillusioned populace.
FACT: The Japanese government is JUST beginning to, after half a century, admit the existence of 'comfort women' during the 2nd world war.
In Japan, bullying has evolved into such an art form, both in schools and the workplace, that it is almost impossible to detect; again, due to shame and embarrassment by the victim of being labelled a 'weakling' if found out. The bullying can get so bad and so frequent that it often leads to suicide. That's why Japan has the highest suicide rate in the world. Since it is suicide, it can not be rated as a crime has been committed, thus the low crime rate.
Also almost all oriental women are basically brought up to be submissive, obedient, and tolerant(in Asia and South-East Asia at least), but this is take to the extreme on Japanese women. Therefore many many crimes against women in Japan were never reported, not even to close family members or friends. (I know this first-hand, ask me via PM if you want more info. Don't want to post details in an open forum).
2) The Japanese embrace their fetish for all things weird and different, instead of frowning upon it. This allows outlets for emotions and desires which would otherwise be bottled up in almost any other society. They have bars where legal-aged women dress up as schoolgirls to entertain those who have such fetishes. They even have vending machines from which you can buy used panties, etc.
The violent, sexually explicit comics is yet another way for the public to 'live' their desire on paper instead of through action.
All these, I believe, are what contributes to the low official crime rate.