Two-color diagram of r′ − i′ and i′ − z′ that is used for our quasar selection. Green plus signs denote point sources with . Blue and magenta squares denote colors of M- and K-type stars (Pickles 1998), respectively. The red line is the median track of the model quasar colors. The red error bars show the standard deviation of the r′ − i′ and i′ − z′ colors in our model quasar spectra. The black solid line shows our photometric criteria used to select quasar candidates at z ~ 5.