Cruise China October 2016

we are on a cruise boat leaving Japan in mid October. After Korea the ship will stay overnight at Beijing so will be able to spend two days there. After two days at sea we will visit Shanghai. We we will have another overnight stay here so will have two days to explore Shanghai. After another day at sea we will disembark the ship at Hong Kong where we are planning on staying in a hotel there for two nights. We will then travel by plane back to Australia. We know we need a Chinese Visa but have been told two different stories by agents. One said a single entry permit is fine but another said we'd need a multi entry one. Lyndall