A method for formatting a magnetic recording disk with patterned nondata islands having alternating magnetization polarity in the along-the-track direction involves clocking write pulses to switch the magnetization direction of alternate, i.e., every other, nondata island. The clocking is controlled by the previously determined phase of the regions containing the nondata islands and the known offset along-the-track between the read head and write head. In each nondata region, every other nondata island in the along-the track direction has the same magnetization direction, with adjacent nondata islands having antiparallel magnetization directions. The disk may be either a horizontal magnetic recording disk, wherein the antiparallel magnetization directions are in the plane of the recording layer and parallel to the along-the-track direction, or a perpendicular magnetic recording disk, wherein the antiparallel the magnetization directions are "into" and "out of" the recording layer.