In a highly unusual move, Japanese authors society JASRAC has issued a warning on its Web site against anyone singing an "altered" version of 87-year-old songwriter Kouhan Kawauchi's 1971 song "O-fukuro-san (Mother)."

The warning specifically mentions enka (ballad) singer Shinichi Mori, who for the past 30 years has been singing a version of the song that includes additional lyrics written by Mori himself.

"O-fukuro-san (Mother)" has become Mori's signature tune, and the artist has unsuccessfully tried to mend fences with Kawauchi. The songwriter reportedly says he won't allow Mori to perform any of his songs again, and Mori says he will comply until he receives "forgiveness" from Kawauchi.