Travelling between Hongkong and Shanghai with a Q2 visa

Henk, this Q2 can be used only once. Once you leave mainland, it will become expired. If you will travel again to Shanghai from HK and then to a third country, you can use the six-day free transit policy in Shanghai and a single entry is enough. If you want to stay more than 6 days after the second entry, you need 2 entries for Shanghai.