The following is an excerpt from a document I compiled as a study aid for a class I am currently teaching on-line via Zoom.
According to some sources this exercise (Liu Zi Jue) originated in the 6th Century and was created by a Buddhist hermit. Other sources trace it to the Six Healing Sounds for Nourishing Life recorded as early as the Qin Dynasty 221-207 BCE. The Six Healing Sounds routine uses breath and sound to purge the organs of toxins and stagnant Qì. The routine is also known as the Six Syllable Secret, Six Exhaling Sounds, Six Qì Method.
The Basics of the Six Healing Sounds
The routine is very flexible. You can use all the sounds together while standing, sitting, or lying down as a complete Qìgo̅ng routine for maintaining or improving overall health. You can use one of the sounds by itself to benefit the organ the sound corresponds to if you feel that the organ is ailing or during the season for the organ according to the Five Elemental Phases Theory. You can incorporate the sounds into Wai Da̅n Qìgo̅ng routines including the Eight Pieces Brocade, the Four Seasons Medical Qìgo̅ng, and the Five Animal Sports.
Theory: The healing sounds are designed to maintain and improve the health of the five yi̅n organs—lungs, kidneys, liver, heart, and spleen—as well as the triple burner, which is basically the torso, which encompassed the organs. Each sound is designed to resonate in its corresponding organ.
The human body is designed to be a self-regulating mechanism that automatically maintains the proper yin̅/yáng balance of each organ and the body as a whole. However, human behavior and lifestyles, stress, improper diet, failure to exercise, etc. can block the self-regulation function. Blood and Qì stagnate within and around the organs. The organs become too yáng (mainly too hot). The interstitial tissues, which normally conduct heat and stale Qì away from the organ, congeal to the organ trapping heat, Qì, and blood causing the organ to malfunction and possibly leading to the formation of tumors. The healing sounds are designed to prevent or relieve this process and help restore the normal self-regulating function.
Posture: The Six Healing Sounds routine can be practiced either sitting on the front 1/3 of a chair seat so that the back of the chair does not press against your back, lying supine (face up) or standing in Wuji posture.
Breathing: Use Return to Childhood Breathing. Breath slowly and evenly. Reverse breathing can be used, but it is difficult to do correctly and can create problems of ̀ stagnation.
Preparation: Meditate and practice Return to Childhood Breathing for a few minutes before beginning the routine. Start the exercise when you feel calm and relaxed with the blood and Qì circulating freely.
Basic Procedure: Imagine that the routine is divided into six parts, one for each organ. In each part the basic procedure is to first focus your mind on the organ. Try to locate and feel its presence within the body. Prepare for the exercise by reviewing an anatomical chart of the organs if you are uncertain as to any organ’s location.
Inhale Qì through your nose, imagining that you are breathing into and filling the organ but not to the point of creating tension.
Then exhale stagnant Qì through your mouth while quietly pronouncing the sounds for the organ. The sounds are: Si (Siiiii, like air leaking from a balloon) for the lungs; Chui (pronounced Ch’way) for the kidneys; Xu (pronounced shu) for the liver; He (like a dog panting) for the heart; Hu for the spleen; and Xi (pronounced like sheee) for the Triple Burner. As you make the sound, imagine the organ vibrating with the sound and imagine stale Qì and heat releasing from the organ into the surrounding fluid and tissue (the interstitium) as well as out through your mouth.
The proper volume level for the sound is called “the sound of no sound.” The sound should be very soft to avoid tensing the throat and vocal cords. Such tension would block the release of stagnant Qì through the throat.
The Number of Repetitions: When performing the sounds on their own, not integrated into other routines such as Eight Pieces of Brocade, the sound should be repeated a minimum of six times for each organ. Complete all repetitions for one organ before moving on to the next. If an organ is ailing, you can do more repetitions for that organ. Sources suggest a range of repetitions from six to 36.
Variations in the Routine
As with any ancient routine, variations have arisen in how to perform the routine. Dr. Yang stresses that Qìgo̅ng is alive, not set in stone, but students naturally want to simplify the process of learning, and sometimes want to be that there is one “correct” way. There is no one “correct” way for everyone. Dr. Yang also stresses “trust your feeling.” When you encounter variations in routines, use your feeling to determine which variation is best for you. It may take time for beginners to develop their feeling, so it is important that they have a qualified teacher whom they can trust.
Sounds: Some sources present slightly different variations of the sounds. You can experiment with the variations to determine which variant works best for you based on the feelings the sounds produce in the organ. Beginner students may be confused by the variations and most will not have developed sufficient inner feeling to test the variations for themselves. Therefore, if you are teaching the routine to beginner students, you may decide not to present variations to avoid confusing or frustrating beginner students.
I have encountered the following variations in the sounds: See-ahh for the lungs. Ch-oo-ay, choo , and chrroooeee for the kidneys. Kher for the heart. Tseh for the Triple Burner.
Enhancements: During the class, we will introduce you to some of the enhancements. You can add the ones you like to your practice. Please note that the routine is not intended to be practiced with all the enhancements together. Attempting to do so would make the practice overly complicated and difficult to do correctly.
Enhancements added to the routine include:
Specific positioning of the teeth, tongue, and lips as you make the sound.
Imagining the release of the Qì from different places in the mouth and tongue as you make the sound.
Making the sounds at a specified musical pitch
Imagining the inhaling of Qì of the color associated with the organ according to the Five Elemental Phases Theory.
Adding specific body postures for each organ.
Imagining inhaling specific virtuous qualities corresponding to the organ.
Imagining exhaling specific negative emotions associated with the organ according to Five Elemental Phases Theory while making the sound.
 I have added tonal marking to the most commonly Chinese terms in the documents for the Medical Qìgo̅ng Exercise Program.