  I summarize the physics results obtained from large-scale dynamical overlap
fermion simulations by the JLQCD and TWQCD collaborations. The numerical
simulations are performed at a fixed global topological sector; the physics
results in the theta-vacuum is reconstructed by correcting the finite volume
effect, for which the measurement of the topological susceptibility is crucial.
Physics applications we studied so far include a calculation of chiral
condensate, pion mass, decay constant, form factors, as well as (vector and
axial-vector) vacuum polarization functions and nucleon sigma term.
