Japan is famous for being one of the safest country in the world. I read stories of lost wallets being frequently returned without any alteration of content. Thefts are very rare indeed, and physical safety is only an issue if you hang out where you shouldn't, like in the Yakuza's world (but even there it's not so bad unless you are looking for trouble).

What abour Korea ? It is so similar to Japan is many ways that it wouldn't surprise me. South Korea is said to be about two decades' behind Japan economically, which places it about just when Japan reached its economic zenith before the bubble burst (no ill omen intended). So Korea should be about as socially developed as Japan in 1990. So is it safe to assume that Korea is as safe as Japan ? (sorry for the pun )