ninja

water

is supposed to be invisible. As such, what if every country has ninjas but we only know about Japans because they are the worst?

What if every country has ninjas but we only know about Japan's because they are the worst?

is always invisible. If you've seen one, you've seen a pretty bad one.

is a kind of expertise whose final test ought to be to put away dishes when one's wife's sleeping in the next room