The correct way to practice and to read "the six healing sounds" according to Master Huai-jin Nan
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According Master Huai-jin Nan's interpretations, the 「6字訣」 means the 「 6 tips訣」 in the practice of breathing when the mouth takes the shape of the 6 Chinese characters when exhaling. These 6 words字訣have to be pronounced in silence.
According to Master Nan, the reason why these 6 tips六字訣 have to be uttered in silence in one of the 3 dialects is that this practice was introduced into China in the Tang and Sung Dynasties when Mandarin was not the national language. The Cantonese, Hakka and Taiwanese dialects were. Master Nan's Zen Seminar: "南懷瑾老師-南禪七日完整版 -- 004" https://www.youtube.com/watch?v=LF_AnQoDE5E&list=PLBD86896B0F2189AB around(1:19:48)
Regarding the scientific connections between breathing and the health of the internal organs please go to my 2 movies, The English one,"Good posture and breathing with Dr. Ho's Integrative Mind Body Training" at 05:39 and the Chinese version of the movie, "IMBT(Integrative Mind Bo...