nippon kokan co ltd diligent service badge

5th class badge. Obverse 鋼 for 鋼管 - Kokan reverse 五級勤功章 - 5th Class Diligent Service Badge 日本鋼管林式會社 - Nippon Kokan Co., Ltd. Nippon Kokan KK began operations in June 1912. In 1936, the company built its first iron and steel plant. In 1940, Nippon Kokan merged with Tsurumi Iron Works...