Obverse
賞 - Award
reverse
海上自衛隊 Maritime Self-Defense Force
幹部候補生学校 - Executive Candidate School/Officer Training School https://ja.wikipedia.org/wiki/%E5%B9%B9%E9%83%A8%E5%80%99%E8%A3%9C%E7%94%9F%E5%AD%A6%E6%A0%A1
According to the case
badge was manufactured by
呉キシヨウ堂 - Kishou-dō...
