Buying and renting out (short-term) a property in Japan

Hi,

I'm considering to buy an apartment in Japan. I'd like to stay there 6 months per year (2×3-months tourist visas) and renting it out the rest of the time.

Has anyone done that? is there any agency that can find tenants and manage the property while I would be away?
I'm not sure of the location yet so any recommendations would be welcome. Naha, Hiroshima, Fukuoka?

Thanks!