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.
師範代 looks almost identical to 師範 but refers to an assistant or deputy instructor ranked below a full 師範.
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.