《黄帝内经·灵枢·根结》
一般针刺的原则是气行滑利的，出针就要早一些；气行涩滞的，出针要就迟一些。
气滑即出疾，其气涩则出迟。
Generally, the principle of acupuncture is that if the Qi flows smoothly, the needle should be removed earlier; if the Qi flow is stagnant, the needle should be removed later.