Any flies in Tokyo?

It’s been about 3 years that I’m living in Tokyo and I still haven’t seen a single fly!

I know this may sound a little bit crazy, but I just wonder why.

Flies are everywhere, even in clean sites they always exist with the only purpose to annoy humans.
Tokyo is a really clean city but that doesn’t mean that dirty zones do not exist. I found places with trash on the street and many other organic dirty things but mysteriously, no flies around…

What about you? Is there some Tokyoite that could confirm me the same?