Visa for stay in China?

We are flying into Shanghai from the UK on 4th July 2018. We then stay in Shanghai for 3 days from 4th July 2018 to 7th July 2018. We then cruise around Japan before returning to Shanghai on Saturday 14th July 2018 and fly back to the UK later the same day. As we are in effect visiting Shanghai on 2 occasions do we need entry permit?