Alpaca Farm in Nagano Prefecture

Hello, I own an Alpaca farm in Ireland, but living in Japan has always been my dream.

Is it possible to open your own activity (like a limited company) in Japan, after regularly buying a property there, and with the time opening an alpaca farm there, or you must be a citizen?

Thank you

If you want to emigrate to Japan, you will need a visa. In your case, it looks like you need a "Business manager" visa to open your own company, and this will also allow you to live in Japan.
https://www.mofa.go.jp/j_info/visit/visa/long/visa1.html

Another aspect - please check if the temperatures in Japan are good for the alpacas, and whether there is enough demand for their wool in Japan to justify running alpaca farm in Japan.

thank you!