Method for correcting position offset of the heads on two dimensional magnetic recording device

A read/write offset correction method applied to a magnetic disk device comprising a disk, a head comprising a write head configured to write data to the disk and a first read head and a second read head configured to read data from the disk, the method comprising:

• generating a correction value based on placement information on the write head and the first read head and the second read head in a case where the first read head and the second read head are placed in tandem along a second direction orthogonal to a first direction coinciding with a radial direction of the disk, a first distance between the first read head and the second read head in the first direction in a case where the first read head is placed at a first position of the disk, and a second distance between the first read head and the second read head in the second direction in a case where the first read head is placed at the first position of the disk;
• and
• correcting as position of said head based on the correction value in a case where first data written with the first read head placed at the first position is read.