  Yukawa production of a light scalar can be explored at a linear collider.
Light (pseudo)scalar can exist in extended Higgs models and an interesting
example is the light pseudoscalar in Type-X two Higgs doublet model. The model
can explain the anomalous magnetic moment of muon at large $\tan \beta$. We
show that the available parameter space in this model can be examined by the
Yukawa process at 5$\sigma$ at the ILC.
