What is the origin of the term turning the light around? It began with the skillful Wenshi (aka Guan Yizi 尹喜, a legendary Taoist in the Zhou dynasty). When the light is turned around, the energies of heaven and earth, yin and yang, all concentrate and solidify. This is what is called “refined thought,” or “purified energy,” or “pure light.”
回光之名何昉乎？昉之自文始真人也。回光则天地阴阳之气无不凝，所谓精思者此也，纯气者此也，纯想者此也。
When you first put this technique into practice, there is seemingly nonbeing within being. Eventually in the course of time, when the practice is completed, you will come to a point where there is seemingly body beyond the body, being within nothingness.
初行此诀，乃有中似无，久之功成，身外有身，乃无中似有。
Only after carrying on concentrated work for a hundred days will the light become real; only then the fire of spirit comes into view. After a hundred days, a dot of true yang energy naturally emerges from the light – a millet pearl is born, just as an embryo engendered from the intercourse of a male and a female. Then you should attend it calmly and quietly. The turning around of the light is the “firing process.”
百日专功，光才真，方为神火。百日后，光中自然一点真阳，忽生黍珠，如夫妇交合有胎，便当静以待之，光之回，即火候也。
In the original creation, there is yang light, which is the dominant energy. In the material world it is the sun; in a human being it is the eyes. Spiritual energy can waste away through the eyes. So the Way of the Golden Flower is practiced completely through the method of reversal.
夫元化之中，有阳光为主宰，有形者为日，在人为目，走漏神识，莫此甚顺也。故金华之道，全用逆法。
Turning the light around is not just turning around the light of one body, but turning around the very essence of Creation. It is not temporarily stopping wandering thoughts, but ultimately emptying the cycles of samsara for all time.
回光者，非回一身之精华，直回造化之真气，非止一时之妄念，直空千劫之轮回。
Therefore each breath corresponds to one year of earthly life; and each breath corresponds to a century drifting in the ninefold darkness of ignorance.
故一息当一年，人间时刻也，一息当百年，九途长夜也。
The majority of people end up pursuing superficial objects and coming to age in conformity with life, without ever looking back. Once their yang energy fades and disappears, they then enter the ninefold netherworlds. The Surangama Sutra says, “Through purified thought one can fly; through emotions one can only fall.” When people are not mindful of their thoughts and emotions, they sink into lower ways. Just by observing clearly and breathing quietly, you can attain perfect enlightenment. This is application of the method of reversal.
凡人自哇的一声之后，逐境顺生，至老未尝逆视，阳气衰灭，便是九幽之界。故《楞严经》云：“纯想即飞。纯情即堕”。学人想少情多，沉沦下道。惟谛观息静，便成正觉，用逆法也。
In the Yin Convergence Classic it says, “The eyes hold the key.” And in the Plain Questions section of The Inner Classic of the Yellow Emperor it says, “All the essence of the human body flows upward and fills the empty apertures of the space (between the eyes).” If one gets this, one has the key to attaining immortality and transcendence of earthly life. This is a shared belief and practice prevalent in all three major philosophies – Confucianism, Taoism, and Buddhism.
《阴符经》云：“机在目”。《黄帝素問》云：“人身精华。皆上注于空窍是也。”得此一节，长生者在兹，超升者亦在兹矣。此是贯彻三教工夫。
The light is everywhere, both inside and outside the body. Mountains, rivers, sun, moon, and the whole earth are all this light, so it is not only inside the body. All the operations of intelligence, knowledge, and wisdom are also this light, so it is not only outside the body. The light of heaven and earth fills the universe; the light of one individual also naturally extends through the heavens and covers all mountains, rivers, and earth. Therefore, once you turn the light around, everything in the world is turned around.
不在身中，亦不在身外，山河大地，日月照临，无非此光，故不独在身中。聪明智慧，一切运转，亦无非此光，所以亦不在身外。天地之光华，布满大干，一身之光华，亦自漫天盖地，所以一回光，天地山河一切皆回矣。
The essence of the body is concentrated upward into the eyes; this is the great key. You should reflect on this. If you do not practice meditation every day, this light flows and gets lost, stopping who knows where. If only you can just sit quietly for a quarter of an hour, you resolve ten thousand kalpas and disentangle a thousand lifetimes. All phenomena revert to stillness. Truly inconceivable is this sublime truth.
人之精华，上注于目，此人身之大关键也。子辈思之，一日不静坐，此光流转，何所底止！若一刻能静坐，万劫千生，从此了彻。万法归于静，真不可思议，此妙蹄也。
Nevertheless, the actual practice proceeds from shallow to deep, from crude to fine. Throughout, it is best to be consistent. The effort is the same from beginning to end, but its experience during the process is personal and only known to oneself. You have got it only when you attain the state where “heaven is open, ocean is unbounded, and all things are just as they are.”
然工夫下手，由浅入深，由粗入细，总以不间断为妙。工夫始终则一，但其间冷暖自知，要归于天空海阔，万法如如，方为得手。
What the sages throughout history have passed on is not departed from ONE thing – internally turning the light around and gazing at it. Confucius calls it “attaining omniscience.” The Buddha calls it “observing the nature of mind.” Lao-zi calls it “inner awareness.” It is all about the same thing.
圣圣相传，不离反照。孔云：“致知”，释曰：“观心”，老云：“内观”，皆此法也。
Anyone can talk about turning the light around, but no one can master it if they don’t really know what the words mean. It means turning away from the discriminating mind and returning to the origin of spirit, the primordial mind. It means using my six-foot body to attain the infinite body of heaven and earth. Nowadays people sit only one or two hours, immersing in their discriminating thoughts, and already they call it “reversing the light” – how can they attain anything!
但反照二字，人人能言，不能得手，未识二字之义耳。反者，自知觉之心，反乎形神末兆之初，则吾六尺之中，反求个天地末生之体，今人但一、二时中间静坐，反顾己私，便云反照，安得到头！
The founders of Buddhism and Taoism teach us to look at the tip of one’s nose. They do not mean that one should focus the mind on the tip of the nose. Nor do they mean that while the eyes are looking at the tip of the nose, the mind should be concentrated on Dan Tian, the Elixir Field. Because wherever the eyes look, the attention follows. How can one’s mind go to different places at the same time? If you don’t realize this, you are taking the finger pointing at the moon for the moon itself.
佛道二祖，教人看鼻尖者，非谓着念于鼻端也。亦非谓眼观鼻端，念又注中黄也。眼之所至，心亦至焉，何能一上而一下也，又何能忽上而忽下也。此皆误指而为月。
Then what does it really mean? The idea of focusing on the tip of the nose is truly clever. It is using the nose as a berth for the eyes, but the nose is not the point here. If you open your eyes too wide, you tend to look into the distance and scatter your attention around. If you close the eyes too tight, you are prone to immerse in reveries and get lost in sleep. It is only when you lower the eyelids halfway, just enough for the tip of the nose to be seen, that you are doing it properly.
毕竟如何？曰鼻端二字最妙，只是借鼻以为眼之准耳，初不在鼻上。盖以大开眼，则视远，而不见鼻矣。太闭眼。则眼合，亦不见鼻矣。大开失之外走，易于散乱。太闭失之内驰，易于昏沉。惟垂帘得中，恰好望见鼻端，故取以为准。
The key is to lower the eyelids just enough, letting in the light naturally. No special effort is needed. The tip of the nose serves as a guideline only at the beginning of meditation, once your focal point is directed, you simply let it be. It is like a mason hanging up a plumb-line. Once he has it hung up, he goes about his work accordingly without looking at the plumb-line.
只是垂帘恰好，任彼光自然透入，不劳你注射与不注射。看鼻端，只于最初入静处举眼一视，定个准则便放下。如泥水匠人用线一般，彼自起手一挂，便依了做上去，不只管把线看也。
Stopping and observing is a Buddhist method that was revealed originally. One sits upright and relaxed, looking at the tip of the nose, and paying attention to Dan Tien, the Elixir Field. It is not necessarily the center of the head, but a point that lies somewhere between the eyes. Light is something fickle and erratic. You just slightly fix the attention on a point between the two eyes, the light will naturally go there. Do not force anything. The words above have summed up all the essential teaching. As for the rest, the prelude and the aftermath, matters of entering and exiting stillness, one can check the book Small Stopping and Observing for further reference.
止观是佛法，原不秘的。以两目谛观鼻端正身安坐，系心于缘中，道言中黄不必言头中，但于两眉中间，齐平处系念便了。光是活泼泼的东西，系念两眉中间，光自然透入，不必着意于中宫也，此数语已括尽要旨。其余入静出静前后，以小止观书印证可也。
The words focus on the center are very delicate. The center is omnipresent; the whole universe is within it. It indicates the inner workings of Creation – through concentration you enter the gate. To focus means to focus on it as a hint, not to become rigidly fixated. The word focus has life to it; it is very subtle.
缘中二字极妙。中无不在，遍大千皆在里许，聊指造化之机，缘此入门耳。缘者缘此为端倪，非有定著也，此二字之义，活甚妙甚。
The words stopping and observing are inseparable, meaning concentration and insight. When a thought arises, you should investigate it: what is this thought? Where does it come from? Where does it go to? Repeat the process until you realize it cannot be grasped; then you don’t need to trace it any more. I have pacified your mind for you.
止观二字，原离不得，即定慧也。以后凡念起时，不要仍旧几坐，当究此念在何处，从何起，从何灭，反复推究，了不可得。即见此念起处也，不要又讨过起处，觅心了不可得。吾与汝安心竟，
This is right view; the opposite to this is false view. Once you realize that thoughts cannot be grasped, you continue to practice stopping and follow it by observing, and continue to practice observing and follow it by stopping. This is the double cultivation of stopping and observing. This is turning the light around. The turning around is stopping; the light is observing. Stopping without observing is called turning around without light; observing without stopping is called having the light without turning it around. Remember this.
此是正观，反此者，名为邪观。如是不可得已，即仍旧绵绵去止，而继之以观，观而继之以止，是定慧双修，此为回光。 回者止也，光者观也。止而不观，名为有回而无光，观而不止，名为有光而无回，志之。
Buddha Mind 