Questions and Answers on the Contemplative Practice of the Four Foundations of Mindfulness 28

Question: Today, at around forty minutes into sitting, I experienced intermittent vibration and trembling from my legs up to my waist, which continued until I got off the cushion. During the trembling there was a slightly pleasant sensation. This has never happened before—what is going on? 

Answer: This is a phenomenon of the qi mechanism being activated, occurring because once the mind has quieted down, the qi channels in the body run smoothly. The qi mechanism usually first arises at the dantian and then moves from the dantian throughout the whole body; its speed and pathways vary from person to person, from time to time, and according to one's physical condition. The arising of both the desire-realm concentration and the first dhyāna of the form realm cannot be separated from the activation of the body's qi mechanism. That is to say, meditative concentration cannot be separated from the activity of the physical body; only when the physical body is free of obstructions can desire-realm concentration and form-realm concentration arise. 

In the future, when the first dhyāna of the form realm arises, it will likewise be the qi channels in the body moving and stirring. That force is not initiated by deliberate mental intention; it arises naturally when body and mind have quieted to a certain degree. Only when afflictions and thoughts arise do obstructions appear, and only then will the qi mechanism in the body recede, and the first dhyāna will disappear along with it. Therefore, the first dhyāna cannot be separated from sitting cross-legged; it mostly arises during sitting meditation. In activity, the duration of meditative concentration is short, and it is not easy to sustain. 

Since cultivating concentration cannot be separated from the body, it cannot be separated from sitting cross-legged. Sitting cross-legged is the foundation for cultivating concentration; the deeper concentrations that follow depend even more on it, because crossing the legs allows the qi and blood to gather and flow smoothly, and both body and mind become stable, so concentration is attained quickly and firmly. Then, taking the concentration attained in sitting as a foundation, one can give rise to and sustain meditative concentration during the activities of the physical body. If one does not sit cross-legged and relies solely on cultivating concentration in activity, first, concentration does not easily arise; second, once arisen, it is not easily sustained; third, deep meditative concentration will not occur; and fourth, contemplative practice (vipaśyanā-caryā) is not easy. Some say that cultivating the Path does not depend on the legs—this is mistaken. If the legs cannot be subdued, the body cannot be subdued; if the body cannot be subdued, the mind cannot truly and lastingly quiet down, and then meditative concentration will not easily appear, cannot be sustained long, and cannot deepen. The practice of the patriarchs of successive generations and of students of meditative concentration has proven this point, and the practice of all Buddhas, Bodhisattvas, Arhats, and Pratyekabuddhas has also proven this point.