China Transit Visa for Guangzhou and Beijing

Hello,

We are Turkish citiziens. We have a plane ticket Turkey to Japan on july 12 with transit Guangzhou. We are going to wait in the airport for 2 hours. And also we have return ticket on july 20 with transit Beijing and we are going to wait in the airport for 6 hours. Do we have to take a transit visa ?
If you can inform us we will be glad
Thanks in advance