A method is designed for embedding an identification code into a musical
apparatus which is allotted a serial number. The method is carried out by
the steps of accepting an input of the serial number by a user of the
musical apparatus, applying a specific operation to the accepted serial
number to generate the identification code which is associated with the
serial number and which is capable of uniquely identifying the music
apparatus, and writing the generated identification code into a specified
address of a nonvolatile memory which is integrated in the music
apparatus such that the written identification code is never rewritten
inappropriately.