镵针即今箭头针，主刺皮肤邪肉侵，毋令深入泻阳气，邪正相安荣卫均。
【注】一曰：镵针式图
[1] 经之一曰：镵针者，取法于巾针，去末寸半，卒锐之长一寸六分。
[2]镵者，锐也；卒者，尾也。
[3]谓此针长一寸六分，上去末寸半，下祗留一寸之锋，
欲浅刺不令深入也。
[4]镵针即今箭头针也，主刺邪热病在头身皮肤之证。
[5]毋令深入，深则有伤阳气。
[6]故必分许浅浅刺之，使邪去而正不伤，荣卫得和，则病除矣。
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员针取法于絮针，主治邪气侵肉分，筩身卵锋不伤正，利导分肉邪自平。
【注】二曰：员针式图
[1]经之二曰：员针者，取法于絮针，筩其身而卵其锋，长一寸六分。
[2]筩身卵锋者，谓身直如作筩，末锋员如卵锐也。
[3]员针即絮针也，主治邪气在分肉之间，盖筩身卵锋，利导分肉，
能使邪气行而不伤于肌肉之正气也。
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鍉针之锐如黍粟，恐其深入伤肌肉，按脉勿陷以致气，刺之邪气使独出。
【注】三曰：鍉针式图
[1]经之三曰：鍉针者，取法于黍粟之锐，长三寸半。
[2]黍粟之锐者，员而微尖，利于用补者也。
[3]鍉针之锋，如黍粟之锐，主治邪在脉中。
[4]不欲深入，祗按脉以候气至，刺脉中之邪气，若使独出也。
[5]深按陷至肌肉，邪风虽出，而肌肉之正气必伤矣。
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The Chan needle (Chan Zhen, sharp-pointed needle) is the arrowhead needle used today. It primarily punctures the skin to treat conditions where pathogenic factors invade and cause abnormal tissue growth (abnormal flesh). One must not insert it deeply to avoid draining Yang Qi, thereby allowing pathogenic and healthy factors to coexist peacefully and ensuring the balance of Ying (Nutritive) and Wei (Defensive) Qi.
[Note] Diagram 1: Style of the Chan Needle
[1] The Classic states: The Chan needle is modeled after the cloth needle. The tip is removed by one cun and five fen, leaving a sharp length of one cun and six fen.
[2] "Chan" means sharp; "Zu" (here read as 'cui' or referring to the end) means the tail/end.
[3] This indicates that the needle is one cun and six fen long in total, with the upper part having one cun and five fen removed from the end, leaving only one cun of sharp point at the bottom.
This design aims for shallow insertion without deep penetration.
[4] The Chan needle is the arrowhead needle used today, primarily treating conditions where pathogenic heat invades the skin of the head and body.
[5] Do not insert it deeply; deep insertion will injure Yang Qi.
[6] Therefore, it must be inserted very superficially, expelling the pathogen while preserving healthy Qi. When Ying and Wei Qi are harmonized, the disease is cured.
The Yuan needle (Yuan Zhen, round needle) is modeled after the wool-carding needle. It primarily treats conditions where pathogenic factors invade the intermuscular spaces (fen rou). Its cylindrical body and ovoid tip ensure that healthy Qi is not injured, facilitating the guidance and resolution of pathogenic factors within the muscles.
[Note] Diagram 2: Style of the Yuan Needle
[1] The Classic states: The Yuan needle is modeled after the wool-carding needle. Its body is cylindrical (tong), and its tip is ovoid (yuan), with a total length of one cun and six fen.
[2] "Cylindrical body and ovoid tip" means the body is straight like a bamboo tube, and the tip is rounded like an egg but slightly sharp.
[3] The Yuan needle is essentially the wool-carding needle, treating pathogenic factors located between the muscle layers. Due to its cylindrical body and ovoid tip, it facilitates the drainage of pathogens in the intermuscular spaces,
allowing pathogenic factors to move and exit without injuring the healthy Qi of the muscles.
The Di needle (Di Zhen, blunt needle) has a tip as fine as millet grains. One fears it may penetrate too deeply and injure the muscles. By pressing on the pulse without sinking the needle, one induces Qi arrival; needling causes the pathogenic factor in the vessels to exit alone.
[Note] Diagram 3: Style of the Di Needle
[1] The Classic states: The Di needle is modeled after the sharpness of millet grains, with a total length of three cun and half a cun.
[2] "Sharpness of millet grains" refers to a tip that is round and slightly pointed, suitable for tonification methods.
[3] The tip of the Di needle resembles that of millet grains, primarily treating conditions where pathogenic factors reside within the vessels.
[4] Deep insertion is avoided; instead, the vessel is pressed to await the arrival of Qi. Needling targets the pathogenic factor in the vessel, causing it to exit exclusively.
[5] If pressed deeply into the muscle layer, although wind-pathogens may exit, the healthy Qi of the muscles will inevitably be injured.