Spatial distribution of z ~ 6 galaxy candidates around the four QSOs (magenta thick circles) overlaid on the LBC z-band images. Red and green circles indicate our primary and secondary candidates. The small blue dots mark the faint i-band dropouts (25 < z₈₅₀ < 26.5) found in the previous study of K09 carried out with HST/ACS observations. The 3 × 3 arcmin² ACS FoV is shown by the blue squares.