SDSS spectra of the six strong-lens candidates with evidence of higher-redshift emission lines. In each panel, the grey line represents the observed spectrum and the black line represents the SDSS-provided best-fit model spectrum (only for the foreground lens galaxy). The top row shows 30 Å windows centred on the detected emission line for HSC J020241−064611, HSC J125251+005805, HSC J141930+434129, HSC J233311 +022311, and HSC J234248−012032, and the bottom row shows the full optical spectrum for HSC J101734−001227. Several emission lines not associated with the redshift of the foreground galaxy (i.e. z = 0.4647) are shown in the zoomed-in images in the insets of the bottom panel. They are found to be coincident with the locations of [O II] doublet, Hβ, [O III] 4960, and [O III] 5008 at z = 0.8457.