Fu (Floating), Chen (Deep), Chi (Slow), and Shu (Rapid) are the four primary pulse types in TCM. Mastering these four pulse qualities allows practitioners to understand many basic health conditions, as they encompass the concepts of exterior and interior, cold and heat, and the four of the eight principles. The Fu and Shu pulses are associated with Yang, while the Chen and Chi pulses are associated with Yin, thus incorporating the Yin-Yang theory. Generally, these four pulses can differentiate between Yin and Yang, exterior and interior, cold and heat, as well as the nature and location of the disease. Therefore, these four pulses serve as the foundation of pulse diagnosis, while the remaining twenty-four pulse types are mostly extensions and variations of these four.
The Shu pulse is the opposite of the Chen pulse; the Chen pulse is Yin, while the Shu pulse is Yang.
According to the Pulse Classic: The Shu pulse has six beats per breath. This means that during one inhalation and exhalation of the physician, the patient’s pulse beats six times. The Shu pulse indicates that Yin cannot overcome Yang, resulting in an excessive pulse.
The Shu pulse generally indicates heat conditions. If we also consider the pulse position, Fu Shu indicates exterior heat, while Chen Shu indicates interior heat. If we can identify the strength of the pulse based on the Shu pulse, a strong Shu pulse indicates excess heat, while a weak Shu pulse indicates deficiency heat. Furthermore, differentiating between the strength and weakness of the pulse, a strong Shu pulse indicates lung abscess, while a weak Shu pulse indicates lung atrophy; a thin and rapid pulse indicates Yin deficiency heat, while a strong and rapid pulse indicates sores and ulcers, and a slippery and rapid pulse indicates phlegm-heat.
However, not all Shu pulses indicate heat conditions; some may indicate cold conditions. If the pulse is Fu Shu, large and weak, and feels empty upon slight pressure, this is a critical condition, indicating excessive Yin below, forcing Yang outward, with the floating pulse indicating that the patient should exhibit symptoms of body heat and a red face. Therefore, a Shu pulse that is soft, large, and without root is a critical condition, and not all Shu pulses indicate heat; such a pulse should not be treated with heat-clearing or Yin-nourishing methods.
The Shu pulse is characterized by an increased pulse rate, with a heartbeat exceeding 90 beats per minute. In children, this is considered a normal physiological pulse (around 110 beats per minute), and in infants (around 120 beats per minute). Sometimes, normal individuals may also exhibit a rapid pulse during exercise or emotional excitement, which is a normal physiological phenomenon and should not be considered pathological.
The following is excerpted from the Binhu Pulse Studies
Body Condition Poem: The Shu pulse has six beats per breath, with Yin weak and Yang strong, leading to agitation. Fu and Chen differentiate between exterior and interior, only children are seen as auspicious.
Similar Poem: The Shu pulse has one more beat than a normal person, tight like a string. A Shu pulse that stops at intervals is called Cu (Interrupted), and a Shu pulse seen at the Guan (Barrel) position indicates movement.
(A Shu pulse that is tense is tight, flowing is slippery, Shu with stops is Cu, excessive Shu is extreme, and Shu seen at the Guan position indicates movement.)
Pathology Poem: The Shu pulse indicates Yang heat, which is evident; just use the fire of the monarch to treat. It is appropriate to cool and drain for excess, and warm and tonify for deficiency; lung diseases in autumn should be feared.
For Cun Shu (Cun pulse), throat and tongue sores, coughing up blood, and lung ulcers. When the stomach fire combines with liver fire, the Chi pulse should be treated with Yin-nourishing and fire-reducing decoctions.
(The Shu pulse indicates the bowels; a strong pulse indicates excess heat, while a weak pulse indicates deficiency heat. Fu Shu indicates exterior heat, while Chen Shu indicates interior heat; a rapid pulse indicates excess lung abscess, while a weak rapid pulse indicates lung atrophy.)