三軍旗羽之分
Distinguishing the Three Divisions by Flags and Plumes
經卒者,以經令分之為三分焉:左軍蒼旗,卒戴蒼羽;右軍白旗,卒戴白羽;中軍黃旗,卒戴黃羽。
Organizing the troops means dividing them into three divisions by standing orders. The left division carries blue-green flags, and its soldiers wear blue-green plumes. The right division carries white flags, and its soldiers wear white plumes. The center division carries yellow flags, and its soldiers wear yellow plumes.
Notes
The color assignments follow Five Phases (五行) associations: 蒼 (blue-green/east), 白 (white/west), 黃 (yellow/center). This color-coding system allowed instant visual identification of unit affiliation on the battlefield, preventing friendly-fire incidents and enabling commanders to track troop movements.
