Seoul-Shanghai-Kunming-Kathmandu

I'm planning to travel from South Korea to Nepal with two intermediate stops in China. I will not leave Pudong Airport as I only have a 3 hour layover, but I have 13 hours in Kunming and would like to see the city. I will be in China for a total of 21 hours. Judging by the answers to other questions, it seems like the visa-free transit does not apply in this case, and I will have to arrage a visa - is that right?