Zhou Jiande nodded gently; indeed, when it comes to the advance and retreat of needles, the acupuncture books all say the same thing, without any doubts, naturally requiring no further discussion.
"The issue lies only in the differing views on divisions. According to 'shallow first, then deep,' it means to advance slowly and retreat quickly; whereas 'deep first, then shallow' could be considered as advancing quickly and retreating slowly, a word transformation essentially indicating that the insertion and extraction for Mountain Burning Fire and Heaven-piercing Cold should follow the principles of slow and rapid replenishing and draining.
Therefore, if we consider the mechanism, interpreting 'shallow first, then deep' as 'two advances and one retreat' or 'three advances and one retreat,' and 'deep first, then shallow' as 'one advance and two retreats' or 'one advance and three retreats,' does not contradict the principles of slow and rapid replenishing and draining.
