Opening small business in Japan.

Hello I just started an internet retail business in California and want to bring my store to Japan, Ive lived in Hyogo pref and Osaka for a year working part-time and studying at language school so I know the language, culture, etc. The only obstacle i have is the immigration system, trying to find the right visa and figuring out the local business laws, any help would be greatly appreciated thankyou.

You need a working visa as "Investor/Business Manager". The rough prerequisites are outlined here:
http://www.mofa.go.jp/j_info/visit/visa/appendix1.html

Among them is the following:
"The business concerned is maintained with the scale of employing at least 2 full-time employees in Japan (Japanese nationals or permanent residents)".