Obverse
賞 - Award
海軍記念日展覧會 - Navy Commemorative Day Exhibition
reverse
海軍協會 - Navy League
佐賀縣支部 - Saga Prefecture Branch
in the center of reverse
勝て兜の緒を締めよ = 勝って兜の緒を締めよう
"After victory, tighten your helmet cords" i.e. even after a victory, prepare for the next battle and do not let your guard down.
and year
二五九七 = 2597 = 1937