  We explore the prospect of Yukawa production of a light boson which can exist
in an extended Higgs sector. A particularly interesting case is the light
pseudoscalar in Type-X two Higgs doublet model which can explain the anomalous
magnetic moment of muon at large $\tan\beta$. Considering ILC $Higgs$ $factory$
with $\sqrt{s}=250$ GeV, we show that the available parameter space can be
fully examined by the (tau) Yukawa process at $5\sigma$. We also demonstrate
the mass reconstruction of such a light particle which helps to sizably
minimize the background events.
