Obverse
Police emblem
+
熊 for 熊本縣 - Kumamoto Prefecture
reverse
陸軍特別大演習御警衛記念 - Army Special Large Maneuvers Imperial Security Guarding Commemorative
昭和六年 - 1931
熊本縣 - Kumamoto Prefecture
Original case.
Badges were manufactured by Naigai workshop /内外徽章製作所/.