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The unique combination of superb spatial resolution, wide-area coverage, anddeep depth of the optical imaging from the Hyper Suprime-Cam (HSC) SubaruStrategic Program is utilized to search for dual quasar candidates. Using anautomated image analysis routine on 34,476 known SDSS quasars, we identifythose with two (or more) distinct optical point sources in HSC images covering796 deg^2. We find 421 candidates out to a redshift of 4.5 of which one hundredor so are more likely after filtering out contaminating stars. Angularseparations of 0.6 - 4.0" correspond to projected separations of 3 - 30 kpc, arange relatively unexplored for population studies of luminous dual quasars.Using Keck-I/LRIS and Gemini-N/NIFS, we spectroscopically confirm three dualquasar systems at z < 1, two of which are previously unknown out of eightobserved, based on the presence of characteristic broad emission lines in eachcomponent, while highlighting that the continuum of one object in one of thepairs is reddened. In all cases, the [OIII]5007 emission lines have mildvelocity offsets, thus the joint [OIII] line profile is not double-peaked. Wefind a dual quasar fraction of 0.26+/-0.18% and no evidence for evolution. Acomparison with the Horizon-AGN simulation seems to support the case of noevolution in the dual quasar fraction when broadly matching the quasarselection. These results may indicate a scenario in which the frequency of thesimultaneous triggering of luminous quasars is not as sensitive as expected tothe cosmic evolution of the merger rate or gas content of galaxies.

Dual supermassive black holes at close separation revealed by the Hyper Suprime-Cam Subaru Strategic Program