Take a hanging ancient bell for example(Figure 1), inside the bell frame there is a string hanging vertically at the center. The end of the string ties a deadweight.
Think of this as a line with nodes and antinodal points. The crown of the head should feel as though suspended creating a main upper nodal point, the perineum is pulled down acts as main lower nodal point.
The vertical line associated with the string of the ancient bell can be divided into four sections; thus defining five points. (Figure 2) 4 resonators, 3 antinodes, and 2 nodes which may become antinodes.
(A) the vertex: located in the throat of the human body, is the spot where one can point at and attack the associated acupoint. It is also known as the deadly-point because it is not easy to move. It is equivalent to the front sight of a rifle which can be used to evaluate how the opponent’s body changes and moves. The vertex may respond as node or antinode.
(B) the upper dead point: being pulled by and hanged from the vertex, its motion range is small. A force applied here is not easy to be neutralized thus this point is call dead point.
A node point may respond as an antinode to a force applied if one is aware of it as a nodal point.
(C) the agile point: this point corresponds to the heart area. It is the most agile point in terms of body rotation, and is also the most difficult spot to be controlled. When doing push hand, one can probe this point to detect the reaction and then attack the dead point.
(D) the lower dead point: influenced by the hanging dead weight, this point’s range of motion is limited. The impact is more effective when applying the internal strength (Jin) towards this point.
(E) the pendulum point: located at the bottom of the vertical line, is where the dead weight is located. This point is in between the two hip joints. Once it moves, it affects the whole body, so it is usually used to stabilize the lower body.