Shangwan (CV13, one acupoint, located five cun above the umbilicus, moxibustion for fourteen burns, treats regurgitation.) Zhongwan (CV12, one acupoint, located four cun above the umbilicus, moxibustion for fourteen burns, treats regurgitation.) Xiawan (CV10, one acupoint, located two cun above the umbilicus, moxibustion for fourteen burns, treats regurgitation.) Tianshu (ST25, two acupoints, located two cun lateral to the umbilicus on both sides, moxibustion for twenty-one burns.)

The *Huangdi Neijing* (Yellow Emperor's Inner Canon) states: In years characterized by the virtue of transformation and maturation, the diseases are primarily Pi syndrome (obstruction/stagnation). It also says: When Taiyin dampness prevails, conditions such as scrofula, accumulation of fluid retention, and Pi-ge (obstruction in the chest/diaphragm) occur.
The *Yuanbing Shi* (Original Causes of Diseases) states: "Pi" is synonymous with "Pi" (as in hexagram Pi), referring to a state of non-circulation or blockage. When the textures through which spirit, Ying (nutritive Qi), Wei (defensive Qi), blood, and body fluids circulate become closed and dense, Pi syndrome forms.

Cheng Wuji stated: In Shanghan (cold damage disease), if there is fullness and obstruction in the epigastrium without prior purgation, there may be differences between vomiting and purging; if it occurs after purgation, there is a distinction between Jie Xiong (chest binding) and Pi Qi (obstruction qi).
If epigastric fullness and obstruction occur without prior sweating or purging, emetic or purgative methods should be employed, depending on whether the pathogenic factor is high or low, to drain it accordingly. If the pathogenic factor is in the exterior and purgation is forcibly applied when not indicated, the pathogen will enter the deficiency and bind in the epigastrium. In cases of excess, hardness, fullness, and pain occur, termed Jie Xiong; in cases of deficiency, fullness without pain occurs, termed Xu Pi (deficiency-type obstruction). These must be carefully distinguished to apply the subsequent treatment methods.

Shanghan-induced Pi-fullness arises because cold damages the Ying blood. Since the Heart governs blood, when the pathogen enters the root, it results in epigastric Pi. The several formulas of Xixin Tang (Heart-draining Decoction) by Zhang Zhongjing all use Huanglian (Coptidis Rhizoma) to drain the earth-pathogen in the epigastrium. Regarding miscellaneous diseases such as alcohol accumulation, excessive purgation can also cause Pi-fullness; this too is a blood-level pathology. Why? Because excessive purgation leads to the loss of Yin. Loss of Yin damages the Spleen and Stomach, specifically depleting the Yin of water and grain within them. Consequently, the Qi in the chest and the blood become deficient and sink into the region of the Heart, causing epigastric Pi-fullness. Treatment should focus on regulating the Spleen and Stomach and addressing the blood aspect. If only Qi-regulating herbs are used for unblocking, the Pi will worsen. Further purgation would cause the Qi to descend further, inevitably transforming into abdominal distension and drum-like bloating, which is incorrect treatment.
*Cishi Nan Zhi* (Difficulties in This Matter) states: Pi from Shanghan originates from the blood level, moving from the exterior to the interior, and is formless; Pi from miscellaneous diseases also originates from the blood level, moving from the interior to the exterior, and is formed. Therefore, formless Pi is treated with bitter-draining methods, while formed Pi is treated with acrid-dispersing methods. *Yuji* (Jade Machine) states: Patients with Pi-fullness know that their Qi is not circulating. Only Li Dongyuan pointed out that this is a blood disease, stating that excessive purgation loses Yin and damages blood, a theory previously unexplored by earlier scholars. The reason why using Qi-regulating herbs to treat Pi often fails in the world is precisely due to ignorance of this principle.