A method for making a master disk to be used for nanoimprinting patterned-media magnetic recording disks uses sidewall lithography. In one implementation, the master disk substrate has a first pattern of concentric rings formed on it by sidewall lithography, followed by a second pattern of generally radially-directed pairs of parallel lines, also formed by sidewall lithography, with the pairs of parallel lines intersecting the rings. An etching process is then performed, using the upper pattern as an etch mask, to remove unprotected portions of the underlying concentric rings. This leaves a pattern of pillars on the substrate, which then serve as an etch mask for an etching process that etches unprotected portions of the master disk substrate. The resulting master disk then has pillars of substrate material arranged in a pattern of concentric rings and generally radially-directed pairs of parallel lines.