Xing Yi Quan (Hsing-I Chuan) is the oldest and the most explosive and aggressive of the neijia (internal martial arts). "Xing" refers to form or shape and "Yi" refers to the mind or intent. Quan means fist, but denotes a method of unarmed combat (boxing, or fist method). Xing Yi Quan is commonly referred to as Mind Form or Mind Intention boxing. The name illustrates that the form the body takes is an external manifestation of the internal state of mind. The mind visualizes a shape and the body takes that shape. The mind visualizes the opponent and the state of combat, and creates the shape that will give strategic advantage. The body then takes that shape. Xing Yi was created by the Song Dynasty general, Yue Fei. The body moves from complete stillness into rapid co-ordinated strikes and it is said that "when the fist arrives, the whole body arrives". The basic practice of xing yi quan consists of standing meditation and the linear repetition of five fist techniques called the five element fists.