Kyusho, pressure point
kyūsho, 急所, Pressure point in martial arts and Ninjutsu, is an anatomical area that is used to inflict pain, cause injury or death. Kyushu, pressure points, in Ninjutsu, is always a reference to physical vulnerable structures and not acupuncture or "energy channels".
The use of Kyusho in Martial arts and particularly in Ninjutsu techniques can give an advantage against a stronger opponent. Many Kata call for the use of Pressure points to direct the opponent's center of gravity or to neutralize him according to the Level of violence.
Image of Kyusho chart of pressure points (abbreviated)
Video of pressure points in arm, Jakkin (Jakotsu) and Hoshi