Cruise Itinerary

Hello will the following work for two 144 hour visas?

Arrive to Shanghai from US, depart on cruise embarking in Shanghai and disembarking in Japan.

The cruise makes the following stops:
Shanghai > Inchon, South Korea > Tianjin, China > Jeju Island, South Korea > Disembark Japan

I understand you have to be transiting to another country but is the Tianjin 144 hour free-waiver invalid because of the stop in Korea before and after or does the final destination of Japan count and the less than 24 hours in Korea for each stop count as in-transit time to Japan?