cruise departing Hong Kong, port stop in Xiamen, additional port stop, Shanghai

I need clarification on whether or not I need a visa, or does the 144 hour exemption apply? I'm boarding a ship in Hong Kong on December 7th, the next stop is December 9th in Xiamen. This is followed by a day at sea, then followed by a 2 day stop in Shanghai. We depart from Shanghai on the 12th, headed for Japan.
From December 7th till December 12th is 5 or 6 days. Thank you in advance for your assistance.