Does 144 Hour Visa Appy to this Itinerary?

We will be arriving in Tianjin on a cruise ship coming from Japan. We depart the same evening to South Korea. We return on the cruise ship to Shanghai two days later again leaving the same evening to Japan. From what I read it seems like the 144hour free transit should apply as we are coming in and leaving to a third country each visit. The cruise line agents don't seem to know but tells us we should get a visa for Tianjin.

The itinerary is: Japan to Tianjin to South Korea to Shanghai to Japan.
Does the 144 Hour free transit apply to this itinerary?