One Way Intl Flights

I plan on flying around Asia on one way flights. I will have the entire trip booked before leaving, so I'm able to show onward flights at each stop. I'm a UK citizen who lives in Japan. That being said, I will go from Tokyo>Seoul>Shanghai>Taipei>Macau>Manila>Tokyo. I'm guessing I will be ok for a few days in Shanghai even with one way flights because I will have proof of onward travel, and will be traveling to other countries before and after I reach China.