Reverse
埼玉縣立工業學校 [= 埼玉県立大宮工業高等学校] - Saitama Prefecture Omiya Technical School [= Saitama Prefectural Omiya Technical High School]
School was established in 1925 and still active today https://omiya-th.spec.ed.jp/.
at the center
工 for 工業 - Technical; Industrial [Manufacturing]
Watch fob was once in the H.F. Bowker East Asian Collection. Original paper case with a rather entertaining watch fob description.