Japanese edit

For pronunciation and definitions of へんか – see the following entries.
変化
[noun] change in society, climate, or condition, transformation, variety
[noun] variation
[noun] declension
[noun] (sumo) a step to one side during the tachiai, the initial charge at the start of a sumo match; a sidestep
[verb] to change, to vary
返歌
[noun] response song; song in return
(This term, へんか, is the hiragana spelling of the above terms.)