According to the Economist’s The Safe Cities Index 2015 Tokyo is the safest city in the world:

Tokyo (1) comes top in the overall Safe Cities Index 2015. The Japanese capital performs most strongly when it comes to the security of its technology assets: it tops the list in the digital security category, three points clear of Singapore in second—the widest gap at the top of any of the four categories. Tokyo also ranks in the top five for personal safety and infrastructure safety, despite suffering regular earthquakes and being home to the world’s largest urban population (38m, according to the UN).

It is a great city to live in, if a little big.