Comparison of the Mg II– and C IV–based BH masses for the HSC quasars whose masses have been measured with both emission lines (J0859+0022, J1152+0055, and J2239+0207). The Mg II–based mass shown in this figure is based on the calibration of Vestergaard & Osmer (2009). We show the C IV–based mass based on Vestergaard & Peterson (2006) with open symbols and Coatman et al. (2017) with filled symbols. The latter calibration takes into account the C IV blueshift with respect to the systemic redshift. The systematic uncertainties of the mass measurements (0.5 dex) are shown by the black point in the lower right corner.