Balance and Move the Qi
This technique is the insertion of very thin, filiform needles into certain points or regions of the body to produce balance and movement within the system.
The needles used in acupuncture are much smaller than your normal doctor's needles, most about the size of a hair. Acupuncture does produce different sensations for different people, ultimately resulting in a peaceful, calm feeling.
The Chinese understood that there was no spontaneous production of energy upon inserting acupuncture needles. The idea was to move the Qi of the body in such a way to produce better function. With better function comes less pain, improved sleep, digestion, and energy.