Japan is, by almost any criteria, an extremely safe country. You can wander most back alleys of Tokyo in the dead of night without any sense of danger, and calmly carry huge amounts of cash secure in the knowledge that you’re about as likely to come across a mugger in downtown as a man riding a horse.
While this bubble of safety is definitely a plus when you’re inside it, the flipside is that Japanese travelers, unaccustomed to street crime, violent or otherwise, tend to be extremely risk averse when going abroad. Driving this point home is the East Africa edition of a popular series of Japanese guidebooks, which is filled with warnings of danger that seem more like something out of a pulp action novel than a travel reference.