Badges were issued by Army Weapons Administration Headquarters to the winners of skill training competition that was held every six months "with the aim of improving the technical skills of the arsenal workers and preparing them for efficient use of these skills in the battlefield". Army Weapons Administration Headquarters was established in October 1942 by integrating the Ministry of Army Weapons Bureau, Army Arsenal, and Army Technical Headquarters in order to centralize the work related to weapons. Eight departments were established under it: general affairs, technology, armaments, supply, education, research, accounting, and medical affairs, and the Army Weapons School, the Army Weapons Arsenal, the Army Weapons Supply Depot and the Army Technical Research Institute were placed under their respective controls. First award ceremony was held on January 18, 1943.
Badges were issued in two grades. Each grade had two classes.
甲 - Kō (1st grade/rank)
乙 - Otsu (2nd grade/rank)
In turn every grade was divided into two classes:
第一種/第壹種 - 1st class
第二種/第弐種 - 2nd class
So there were four different badges.
Kō badges.
甲技能章第一種 - 1st grade 1st class
甲技能章第二種 - 1st grade 2nd class
Otsu badges.
乙技能章第一種 - 2nd grade 1st class
乙技能章第二種 - 2nd grade 2nd class
These inscriptions (that could be found on badge reverse) are the easiest way to determine (with certainty) the class of your badge.
All known badges were manufactured by Naigai workshop in Tokyo https://asiamedals.info/threads/badges-labels-and-marks-of-naigai-medal-works.21286/
