Flow chart illustrating the lensed quasar candidate selection procedure. The effective region (Eqs. (10)–(12)) and number of blobs (Eqs. (14)–(17)) are calculated for each variable object from the HSC transient survey (HSC variable). The HSC variables with the number of blobs larger than N_crit are preselected. The percentile of the effective region for each epoch from all the HSC variables that remain after the preselection on the number of blobs is calculated. Finally, two thresholds, p_thrs% and N_thrs, are set; the HSC variables are selected that have an effective region larger than p_thrs% percentile for more than N_thrs epochs, as lensed quasar candidates.