Do I require a visa to Beijing

Actually, it seems that you are eligible for 144 hours visa free transit in Beijing. Of course, you have to fulfill the following requirements:

- Your flight from Europe to Beijing should not have any additional landing within mainland China and in the country that will be your first destination of your cruise, immediately after you leave Tianjin.
- Your cruise should not have, as the first port call, immediately after Tianjin, in mainland China. I think that your first port call, immediately after Tianjin is Fukuoka in Japan, so this part should be just fine.

So, if your entire itinerary complies with the above mentioned requirements, then you are definitely eligible for 144 hours visa free transit in Beijing area and you don't need any kind of visa. Please, just check whether you are fine with the above requirements and that's it.