indian passport and applying for a business trip in china from Japan

Dear, before answering you this question, I need to tell you that: in order to apply for a visa in Jpan, non-Japan citizens shall provide documents that entitle them to reside for an extended period of time in Japan. Temporary visitors to Japan should apply for a Chinese visa in their own country. For the special cases, consular officer has the rights to make the final decision on whether issuing a visa or not.

Therefore, I guess you need to go back to your country to apply. Anyway, you can have a try at the CVASC in Japan to see if your case belong to the so-called special cases.