An example of our mock galaxy catalogs for testing cluster-finding algorithms. Small gray dots show the distribution of “field” galaxies, taken from real HSC observations. Red squares, magenta triangles, and blue circles show the distribution of “cluster” galaxies at redshift 0.3 < z < 0.6, 0.6 < z < 0.9, and 0.9 < z < 1.2, respectively. (Color online)