The cultivation of Song is a critical concept in the mastery of T'ai Chi Ch'uan. There are six levels to the mastery of song.
- 松開 Song Kai - Opening "Song" .. opening the joints and relaxing the muscles so that the Qi can begin to move.
- 松沉 Song Chen - Sinking "Song" .. relaxing the whole body but especially the groin area so that the Qi can "sink" to the Dan Tian and then relaxing the legs so that the Qi can sink to the feet.
- 松散 Song San - Dispersing "Song" .. reaching this level means that you are able to disperse the Qi to the limbs ... the Qi will never reach the fingers until you achieve this level of Song.
- 松淨 Song Jing - Clean "Song" (also known as Fang Song 放松 - completely relaxed or pure "song") .. this level means that you have relaxed your mind so much that you can return to the state of a baby's mind, careless and free of worry. This stage is necessary for Shen Ming or the state of the spirit relaxing or not worrying that you may die.
- 松通 Song Tong - Communicating "Song" .. this level means that you can remain "Song" while receiving your opponents force and sending him straight back out without tensing the slightest muscle. At the end of the softest soft is the hardest hard ... your opponent will never find the hard and the end of your soft until you reach this level of Song.
- 松空 Song Kong - Empty "Song" .. this is the highest state and is the basis for the phrase "I alone know the opponent and he does not know me." In this state you are able to turn off your opponents ability to Ting (listen) and attack freely. The first 3 are training for Song. The 4th is a final state of "static" song. The last 2 are the advanced levels of "dynamic" song or "song" for fighting.