Releasing or draining a certain amount blood from the body for therapeutic purposes is an ancient practice, already known for centuries, if not for millennia, in ancient Greece, India, Tibet, and China, among other civilizations.
This type of treatment is commonly known as bloodletting. In Japan, this practice is called Shiraku, typically carried out with needles or lancets, usually in conjunction with a regular acupuncture treatment.
In fact, it’s thought that acupuncture therapy was originally a type of bloodletting, and the needles (or lances) used were applied on acupuncture points located on veins to drain the blood.
The idea behind Shiraku is that bloodletting can be used to free the flow of Ki Life Energy, which is believed to partly reside in our blood. Another thought behind bloodletting is the notion that it draws out toxins, a practice also known in cupping therapy.