Inquiry on notarization of will made out of China

The following is an inquiry I receive from a HK lawyer regarding notarization of wills. As it may be a general issue among people living outside China mainland, I publish the question and answer here for your reference.

Dear Sirs,

I am a Hong Kong solicitor. I have a client who want to make a will in Hong Kong but she has property in Shanghai.
I will write a will for her.…