demon's prayer (Ōtsu-e motif)
Refers to a specific motif in Ōtsu-e folk paintings: a demon dressed as a monk holding a bell. The phrase is not used as a general idiom outside this art context.
See also: 大津絵
In Ōtsu-e, there is a famous motif called 'demon's prayer'.
Literally 'demon's nembutsu (prayer)'. The phrase is a fixed name for a well-known Ōtsu-e painting subject; the exact origin of the motif is uncertain.