noun
Ground Officer Candidate School
Specific organization name; refers to a military training institution for officer candidates.
彼は幹部候補学校を卒業して将校になった。
He graduated from the Ground Officer Candidate School and became an officer.
Compound of 幹部 (kanbu, 'executive, officer') + 候補 (kōho, 'candidate') + 学校 (gakkō, 'school').