Question for 5 days stay in Shanghai

We are a family coming from Denmark, but in July (if they fly) to Japan. On the way home we have booked a flight from Osaka to Shanghai and are there for 5 days before traveling home from Shanghai to Denmark. I understand that we will be able to notify the airline in Osaka of our intention to stop in and spend 5 days in Shanghai before traveling home to Denmark, thereby getting a 144 hour visa free transit stamped in our passport. Is that correct understood?