Although the *Neijing* (Classic of Internal Medicine) divides cold and heat syndromes into six channels, the clinical manifestations are merely two: cold and heat. Cold Jue (Cold Reversal Syndrome, characterized by cold extremities) is caused by excessive sexual desire depleting essence, leading to Yang deficiency and Yin excess. When pathogenic factors invade the three Yin channels, the hands and feet become cold, which is called Cold Jue. Hot Jue (Hot Reversal Syndrome, characterized by hot extremities despite internal heat or vice versa depending on stage, here defined as hot extremities due to Yang hyperactivity) is caused by sexual intercourse after drunkenness or overeating; essence deficiency allows heat to enter, resulting in Yin deficiency and Yang hyperactivity. When pathogenic factors invade the three Yang channels, the hands and feet must be hot, which is called Hot Jue. When heat reaches its extreme and develops into reversal cold (Jue Ni), it is Yang at its extreme appearing like Yin; when cold reaches its extreme and develops into reversal cold, it is pure Yin without Yang.

Zhang Zhongjing stated: "The deeper the heat, the deeper the Jue." Therefore, Shanghan (Cold Damage disease), Shibing (Dampness disease), and Wenbing (Plague/Febrile diseases) are all types of Hot Jue. This refers to heat reaching its extreme and developing into Jue, where Yang at its extreme appears like Yin. Although the pulse is deep and hidden, upon pressing it will be rapid (Shu). The etiology is accumulated heat, thus it is called Yang Jue. In the initial stage of Yin Jue, the four limbs are cold, the pulse is faint, deep, and not rapid, with aversion to cold being predominant, and a desire to cover oneself with clothes. Symptoms include diarrhea with undigested food, cold extremities, curling up while lying, cyanosis of the lips, spontaneous diarrhea without thirst, and white urine. The etiology is deep-seated cold, thus it is called Yin Jue.

Zhu Danxi stated: "Jue" means reversal, manifesting as cold extremities, caused by the reversal of Qi and Blood leading to cold. It arises from three conditions: Qi deficiency, Blood deficiency, and Phlegm stagnation. Therefore, numbness of the hands and feet indicates Qi deficiency; insensibility (numbness without pain sensation) of the hands and feet indicates Damp-Phlegm or dead blood (stasis).

Jue syndrome also includes the condition of sudden evil attack, caused by external pathogens clashing with the body. Due to exposure to improper Qi, there is sudden coldness of the extremities, cutaneous gooseflesh, cyanosis and blackening of the head and face, and loss of mental control; or delirious speech, clenched teeth, and locked jaw; or confusion and unconsciousness, dizziness, and fainting. This is called Ke Wu (Guest Clashing), caused by Gui Ji (Ghost Strike), attending funerals, entering temples, or visiting tombs, and is named Fei Shi Cu Jue (Flying Corpse Sudden Jue).

A pulse that is deep, faint, and not rapid indicates Cold Jue. A pulse that is deep, hidden, and rapid indicates Hot Jue.
A pulse that comes rapidly like panting is named Qi Jue, accompanied by unconsciousness.
The *Jingui Yaolue* discusses a pulse that is deep, fine, and slippery: deep indicates cold, slippery indicates Qi excess. When cold Qi and excess Qi clash and enter the Zang organs, resulting in cyanotic lips and cold body, death ensues. If the body remains harmonious/warm and sweat occurs spontaneously, it indicates the pathogen has entered the Fu organs, and survival is possible.