Double-check on a 72-hour transit plan

Hi, I just wanted to double-check a 72-hour transit plan that I have. Thanks in advance!
My trip is planned as follows
Fly from Frankfurt, Germany to Tokyo, Japan and stay in Japan for 2 weeks. Then on my way back, I would like to fly from Tokyo to Beijing, where I stay for 72 hours, and then fly back to Frankfurt from Beijing.

Now I learned that you are not eligible for the 72-hour transit visa if the Departure country and Destination country during the "transit" are the same. In my case, does Japan count as the departure country or is it still Germany, though the flight from Germany to Japan/China is already some weeks ago?

Thanks for your help.