travel information to HK & China.

Hi. Myself and 2 friends booked our plane tickets to Hong Kong from the 18th till the 25th of March. My friend brother stays in HK. We wil stay there. Our main purpose is to visit all areas related to Bruce Lee. All is in china. Where he lived before his death, cumberland str, heratige museum and park up in Foshan. So we will be entering from HK to china several times. Now do we as SA citizens need a visa & must it be multiple.
Some sites on web say its not needed. Help please.