Can I get a Chinese Work Visa in Japan?

Hi,
We are a German/Danish couple, currently living in China on a tourist visa. We would like to change our tourist visas to work visas and for this, we know we have to travel outside the country. As we always wanted to go to Japan, we're now considering a trip to Tokyo in order to get our work visa for China there.

Now here's my question: Is it possible for us to get a Chinese work visa in Japan, even though we are not living there? I read that you need a Japanese alien registration card for applying for any kind of visa? Could we also get that one as tourists? Or does anybody know if we have to go back to our home countries in order to apply for the Chinese work visa?

The laws about Chinese visas are recently changed quite a bit, so I'm very confused about the regulations and would really appreciate if anyone could help!

Thanks, Julia and Jonas