Real Estate interest

I am a Real Estate Detective in Greece and I work individually as an exclusive buyer agent. I am interested in visiting Japan both as a tourist and professional to make contacts to promote my services. Do you think that there is interest from Japanese people to invest in Greece?

Contacts in your own industry would probably know better than anyone here.

You can easily visit Japan on a tourist visa - but can't do business on a tourist visa.

Can you visit Japan? Sure

Is there a large market to Greek properties in Japan? Probably not - or at least not yet.

Others will know more than me - but North Asia often buys property for several reasons

(1) Investment
(2) Lifestyle such as kids going to University.

Japan does not have a large overseas holiday home market like say the UK. It seems as though people from Hong Kong, Singapore, China and to some degree Vietnam tend to buy more overseas properties than Japan. Then again - that might be due to my experiences.

You can do business in Japan on a temporary visitor permit - you are not allowed to "work" in Japan on the visitor permit, but that has a different, specific meaning.
You could certainly make contact with various real estate agents around the country and promote your service. But would you have many clients wanting property in Japan? Costs are high and size small, so might not be what people from Europe are looking for.

"Do you think that there is interest from Japanese people to invest in Greece?"

I think OP question "investment from Japan to Greece".
maybe and maybe not. but, generally speaking, Japanese think that Greece is unstable country.