noun
assistant instructor
A title used in martial arts (e.g., judo, kendo, karate) for a senior student who assists the head instructor. Below 師範 (shihan) in rank.
彼は道場で師範代を務めている。
He serves as an assistant instructor at the dojo.
師範 is the head instructor or master, while 師範代 is the assistant instructor, one rank below.
Compound of 師範 (shihan, 'instructor, master') and 代 (dai, 'substitute, representative'). The term likely originated in martial arts contexts to denote a deputy instructor.