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The Ru (Soft) pulse is extremely soft and floating, thin and fine, resembling silk floating in water. It can be perceived with light pressure, but feels powerless when pressed heavily, like bubbles floating on the surface of water. The image described as "like silk floating in water, disappearing immediately upon heavy pressing" refers to this sensation. The description in *Mai Jue* ("seeming present upon pressing, vanishing upon lifting") actually characterizes the Wei (Minute) pulse, not the Ru pulse. Furthermore, it is stated: "The Ru pulse appears floating, thin, and fine, requiring light pressure; it resembles cotton floating on water, lacking strength." Seeing this pulse after illness or postpartum indicates that treatment is still possible; if seen in a healthy person, it signifies a lack of root. A floating, thin pulse resembling cotton is the Ru pulse; a deep, thin pulse resembling cotton is the Ruo (Weak) pulse; an extremely thin pulse upon floating is the Wei (Minute) pulse; and an extremely thin, unbroken pulse upon deep pressing is the Xi (Fine) pulse.

Diseases governed: The Ru pulse primarily governs loss of blood and Yin deficiency, indicating depletion of the Dantian essence and marrow. It is associated with night sweats, uterine bleeding, and dampness invading the Spleen. A Ru pulse at the Cun (Inch) position governs Yang deficiency leading to spontaneous sweating; at the Guan (Bar) position, it governs Qi deficiency; and at the Chi (Cubit) position, it governs injury to essence, loss of blood, and extreme cold. The therapeutic method should be warming and tonifying. Generally, the Ru pulse governs diseases of Blood deficiency and also indicates injury by dampness.

Extremely soft and deep, it can only be felt with heavy pressure, and is completely imperceptible with light pressure. It is further stated that the Ruo (Weak) pulse is the deep aspect of the Ru pulse. The descriptions in *Mai Jue* comparing it to floating bubbles are incorrect and do not describe the Ruo pulse. *Su Wen* states: "A pulse that is weak yet slippery indicates the presence of Stomach Qi; a pulse that is weak yet choppy indicates a chronic disease." Seeing a weak pulse after illness or in the elderly is a favorable sign (Shun), whereas seeing it in a healthy young person is unfavorable (Ni). It is also said: "The Ruo pulse comes without force, feeling soft upon pressure, thin and deep without any floating quality. This indicates Yang sinking into Yin and deficiency of Essence and Blood." While acceptable in the elderly, it indicates severe illness in the young.

Diseases governed: The Ruo (Weak) pulse governs deficiency of Yin Qi and decline of Yang Qi, manifesting as aversion to cold and fever, flaccidity of sinews and bones, frequent fright, excessive sweating, and diminished spirit. The therapeutic method should be to tonify Qi. A Ruo pulse at the Cun position governs Yang deficiency; at the Guan position, it governs weak Stomach and declining Spleen; and at the Chi position, it governs sinking of Yang and deficiency of Yin. It is also stated: "The Ruo pulse governs diseases of Qi deficiency." Zhang Zhongjing said: "When Yang sinks into Yin, there is aversion to cold and fever." It is also said: "The Ruo pulse governs Sinew issues, while the Deep pulse governs Bone issues. When Yang floats and Yin is weak, Blood deficiency leads to taut sinews." Liu Shi said: "Qi deficiency results in a weak pulse. Weakness at the Cun indicates Yang deficiency; weakness at the Chi indicates Yin deficiency; weakness at the Guan indicates deficiency of Stomach Qi."

The Chi (Slow) pulse is large and soft, feeling powerless upon pressure, with a hollow sensation under the finger. Cui Shi said: "The form is large but the momentum is thin, revealing its deficiency." The statement in *Mai Jue* regarding excess upon searching and lifting merely describes the Floating pulse and fails to depict the deficient state. Yang Shi said: "Its shape resembles willow catkins, scattered and slow." Hua Shi stated: "Scattered, large, and Ru are all types of Scattered pulses, not Deficient pulses." It is also said: "Lifting reveals a slow, large pulse; pressing reveals looseness. The pulse has no boundary, resembling an empty grain husk. Do not confuse the Kou (Hollow) pulse with the Xu (Deficient) pulse. The Kou pulse is slow, floating, and large, resembling a green onion." Furthermore: "The Xu (Deficient) pulse is floating, large, and slow, feeling powerless upon pressure. The Kou (Hollow) pulse is floating and large, feeling hollow in the center upon pressure. The Kou pulse governs loss of blood, while the Xu pulse governs Blood deficiency."

Diseases governed: A deficient pulse with body heat governs spontaneous sweating due to Summerheat injury, palpitations, and fright. It also governs Yin deficiency with fever. The therapeutic method should be to nourish Ying (Nutrient) and benefit Wei (Defensive). At the Cun position, it governs Blood failing to nourish the Heart; at the Guan position, it governs abdominal distension and poor appetite; and at the Chi position, it governs bone-steaming fever, Bi syndrome, flaccidity, injury to essence, and loss of blood. The Classics state: "Blood deficiency results in a deficient pulse. If the Qi arrival is deficient and minute, it is 'not reaching' (Bu Ji), indicating internal disease." It is also said: "For chronic diseases, a deficient pulse indicates death."