Google - seeing specific country only results

[pitpony]

Hi

Could someone explain to me how Google decides which sites to include in the SERPS when you just ask to see pagea from your own country. So for example if you go to Google.jp (Japan) and do a search in Japanese and just ask to see sites from Japan how will Google carry out the search. Does the site need to be hosted in Japan or does ir simply need to have a co.jp domain extension. If the site was written in Japanese but had .com domain and was hosted in the UK would the site still appear in the country only search results. Is it based on the domain name or the place where the site is hosted or both?

Thanks