We need temporary work permits. What visas and paperwork do we need to be able to work in China for 5 days?

Work in China for 5 days only? work visa is not suitable for this, you can try to apply for a business visa instead. In this case, an Invitation Letter of Duly Authorized Unit in China, or Confirmation Letter of Invitation, or invitation letters from the host company, meeting or exhibition organizers in China is required.