assistant chief of staff (G-1)
A specific military staff position, typically in a ground force context, responsible for personnel and administration. The 'G-1' designation is a U.S. Army-style staff section code.
He was appointed as the assistant chief of staff, G-1, in the Self-Defense Forces.
Compound of 第一 (first) + 部長 (department head), used as a specific military staff title.