The map for Chinese embassy in Tokyo is on this website http://www.china-embassy.or.jp/jpn/sgjs/t62814.htm

The requirements for Business Visa:
1. an invitation letter，from the relevant state departments of the PRC, local government above the level of township, relevant companies, business entities or non-profit governmental organizations is necessary for the application.

2. A valid passport with at two blank visa pages and 6 month validity.

3. Certificate of alien registration and its copy

4. One completed visa application form affixed with one recently taken, bareheaded, full-faced photo.