How flexible is flexible with no qualifications?

Can I get a Z visa with no qualifications but with a well written invitation from a credible school??? I have worked at this school in Zhuhai for 2 years (2011-2013) and would gladly do whatever paperwork to get me to stay. If not would a tesl degree qualify for Z?? I am currently in Canada and will sort this out here. Thanks for any future help :-)