Plan cruise on msc start Tokyo Japan, then Busan enter Tianjin

Flying out to Osaka Japan on flight. Can enjoy 144 Visa. Will they consider the cruise from Tokyo or Busan?
If they consider as Busan to TJ to Osaka, then seems okay! If they consider as Japan China Japan then not okay. If they consider Busan TJ Beijing Osaka then again seems not okay. Please help me out or share you travel experience. Thanks 😊