  The process $e^{+}e^{-} \to q\bar{q}$ plays an important role in electroweak
precision measurements. We are studying this process with ILD full simulation.
The key for the reconstruction of the quark pair final states is quark charge
identification (ID). We report the progress of charge ID study in detail. In
particular, we investigate the performance of the charge ID for each decay mode
of the heavy hadrons to know the possibilities of improvements of the charge
ID.
