Chiral Rings Do Not Suffice: N=(2,2) Theories with Nonzero Fundamental   Group
  The Kahler moduli space of a particular non-simply-connected Calabi-Yau manifold is mapped out using mirror symmetry. It is found that, for the model considered, the chiral ring may be identical for different associated conformal field theories. This ambiguity is explained in terms of both A-model and B-model language. It also provides an apparent counterexample to the global Torelli problem for Calabi-Yau threefolds. 
P.S. Aspinwall and D.R. Morrison