Some Wondrous Effects of Inner Calm, as Described and Explained in Yu Yan’s Zhouyi cantong qi fahui Some Wondrous Effects of Inner Calm, as Described and Explained in Yu Yan’s Zhouyi cantong qi fahui

: This essay examines what Yu Yan’s Zhouyi cantong qi fahui says about the suspension of breathing and pulse, as well as the extraordinary inner sensations and visions that accompany it. Yu Yan maintains that these things come about by simply bringing body and mind to the depths of stillness; they are not instigated through deliberate procedures such as holding of breath, visualization, incantation, gulping air, swallowing saliva, etc. Through sheer inner calm and single-minded concentration, breathing and pulse are suspended while an inner qi Abstract: This essay examines what Yu Yan’s Zhouyi cantong qi fahui says about the suspension of breathing and pulse, as well as the extraordinary inner sensations and visions that accompany it. Yu Yan maintains that these things come about by simply bringing body and mind to the depths of stillness; they are not instigated through deliberate procedures such as holding of breath, visualization, incantation, gulping air, swallowing saliva, etc. Through sheer inner calm and single-minded concentration, breathing and pulse are suspended while an inner qi 氣 is generated that surges and circulates the body, bringing forth ravishing sensations and strange visions. Yu Yan explains why the inner qi and the visions come to be generated, and why one should and can disregard the visions. Yu Yan’s descriptions and explanations regarding inner calm and its wondrous effects help shed light on the Neidan (inner alchemy) methods of the major traditions of his time (especially Nanzong and Quanzhen), revealing details that tended to be obscured in abstruse metaphor or reserved for oral transmission. is generated that surges and circulates the body, bringing forth ravishing sensations and strange visions. Yu Yan explains why the inner qi and the visions come to be generated, and why one should and can disregard the visions. Yu Yan’s descriptions and explanations regarding inner calm and its wondrous effects help shed light on the Neidan (inner alchemy) methods of the major traditions of his time (especially Nanzong and Quanzhen), revealing details that tended to be obscured in abstruse metaphor or reserved for oral transmission.


Introduction
Yu Yan 俞琰 (ca. 1253-1314) was a private scholar and lay Daoist Neidan 内丹 (inner alchemy) practitioner who hailed from Wujun 吳郡 (present day Suzhou 蘇州) and was active during the second half of the 13th century. Though he was an erudite Confucian scholar and had in his youth aspired to the civil service, he shunned government service after the Song Dynasty was overthrown by the Mongol Yuan Dynasty. The principal subjects he wrote on were the Yi jing 易經 (Book of Changes) and Daoism-especially Neidan. 1 His reading in Daoism was extensive, as is apparent from the numerous sources he cites in his writings, especially in his collection of notes and anecdotes entitled Xishang futan 席上腐談.  Yi juyao 讀易擧要 (Siku quanshu,vol. 21,, and Xishang futan 席上腐談 (Siku quanshu, vol. 1061, pp. 597-626).

Introduction
Yu Yan 俞琰 (ca. 1253-1314) was a private scholar and lay Daoist Neidan 丹 (inner alchemy) practitioner who hailed from Wujun 吳郡 (present day Suzhou 蘇州) and was active during the second half of the 13th century. Though he was an erudite Confucian scholar and had in his youth aspired to the civil service, he shunned government service after the Song Dynasty was overthrown by the Mongol Yuan Dynasty. The principal subjects he wrote on were the Yi jing 易經 (Book of Changes) and Daoism-especially Neidan. 1 His reading in Daoism was extensive, as is apparent from the numerous sources he cites in his writings, especially in his collection of notes and anecdotes entitled Xishang futan 席上腐談. 2 1 His output as a writer was prodigious, though some of his works have been lost. Preserved in the Daozang 道藏 (the Daoist Canon compiled in 1445) are Zhouyi cantong qi fahui (DZ1005) 周易參同契發揮, Zhouyi cantong qi shiyi 釋疑 (DZ1006), Huangdi yinfu jing zhu 黃帝陰符經註 (DZ125), Yiwai biezhuan 易外別傳 (DZ1009), Xuanpin zhi men fu 玄牝之門賦 (1010), and Lü Chunyang zhenren Qinyuan chun zhujie 呂純陽真人沁園春註解 (DZ136). (The "DZ" number is the number under which the text is catalogued in (Schipper and Verellen 2004)) Also surviving are his Zhouyi jishuo周易集說 (Siku quanshu四庫全 書, vol. 21, pp. 1-394), Du Yi juyao 讀易要 (Siku quanshu,vol. 21,, and Xishang futan 席上腐談 (Siku quanshu, vol. 1061, pp. 597-626). 2 His style name was Yuwu 玉吾. His sobriquet was Quanyangzi 全陽子 (Master of Complete Yang), and he also referred to himself in his capacity as a Daoist as Linwushan Ren 林屋山人 (Man of Mt. Linwu) and Shidong Daoren 石洞道人 (Daoist of the Stone Grotto). According to the Siku tiyao's 四庫提要 entry concerning his work Zhouyi jishuo 周易集說, Yu Yan was born at the beginning of the Baoyou 祐 era (1253-1258) of the Song, and died at the beginning of the Yanyou 延祐 era (1314-1321) of the Yuan. See Heyin Siku quanshu zongmu tiyao ji Siku weishou shumu jinhui shumu 合印四庫全書總目提要及四庫未收書目 禁燬書目, vol. 1, p. 49; (Pregadio 2008) "Yu Yan," in The Routledge Encyclopedia of Taoism, vol. 2, pp. 1190-91;and The Taoist Canon, vol. 3, p. 1286. Yu Yan's Zhouyi cantong qi fahui 周易參同契發揮 (Exposition on the Concordance of the Three According to the Book of Changes; from here to be referred to as the Fahui) 3 is a commentary on the abstruse alchemical classic Zhouyi cantong qi 周易參同契. 4 In his preface to the Fahui (which he wrote in 1284), Yu Yan reminisces that when he first read the Zhouyi cantong qi he could not understand it, hard though he tried. At that time a certain person (or persons) told him that in order to "cultivate the Elixir" (xiudan 修丹), he needed to acquire an "oral lesson" (koujue 口訣) from a Divine Transcendent, and that he was certainly toiling in vain by trying to study on his own from a book. Despite being told this, Yu Yan continued to diligently read and study the Zhouyi cantong qi. Though he did not yet understand this text that he believed so devoutly in, he took heart from the fact that "Sir Wei [Boyang] (putative author of the Zhouyi cantong qi) has stated that after you have [read the text] a thousand times in its entirety and [recited it] ten-thousand times, gods will tell [you its meaning] and your mind will understand." 5 魏公有千周萬遍神告心悟之說 Yu Yan reasoned that the words of such an excellent man certainly could not be deceptive. Yu Yan goes on to reminisce that suddenly one day, after close to a full year of concentrated study of the Zhouyi cantong qi, "my mind became numinous and understood on its own" 心靈自悟; consequently, he "obtained its gates and entered in" 得其門而入. From this point on the text's meaning started to become remarkably clear to him, "as if there were a god telling it" 若有神告之者; yet the fact remained that Yu Yan sadly "had yet to obtain a transmission from a teacher" 未得師承, and thus he could not feel fully convinced of the veracity of what he thought he understood. (See Fahui,prefaces,5b) Yu Yan could thus only continue to ponder the text's meaning, often "throughout the night, forgetting to sleep" 終 夜 忘 寢; yet, his faith became more devout than ever, until it "ultimately evoked a response from an extraordinary person." 遂感異人 This "extraordinary person" bestowed instructions upon Yu Yan that dispelled all of his doubts. When Yu Yan took up the Zhouyi cantongqi after this encounter, he readily interpreted its meaning, and could furthermore see that its teachings corresponded perfectly with those of Liu Haichan's 劉海蟾 Huanjin pian 還金篇, Zhang Ziyang's 張紫 陽 Wuzhen pian 悟真篇, Xue Zixian's 薛紫賢 Fuming pian 復命篇, and Chen Niwan's 陳泥丸 Cuixu pian 翠虛篇. (See Fahui,prefaces,6a) Apparently, in the view conveyed by Yu Yan, reading a text and pondering its meaning can lead to inner awakening and divine revelation. By the sound of things, this "extraordinary person" who instructed Yu Yan may not have been an actual human in the flesh, and the communication perhaps occurred subjectively as a mystical experience. Alleged instances of communications from ascended Immortals are of course rather common in the lore of Neidan (with the most famous of these perhaps being Quanzhen 全真 School founder Wang Zhe's 王 [1113-1170] encounters with Lü Dongbin 呂 洞賓 [b. 798?]). The unique twist here seems perhaps to be that the single-minded study of one specific alchemical text induced the mystical encounter. Yu Yan may be asserting that if one's faith is sincere and tenacious, one can successfully learn and practice Neidan from books, without personal instruction from a teacher (of the ordinary, not-yet-ascended sort). That he would prefer this approach could be understandable in light of the fact that he was not an ordained Daoist, and may have lacked 3 DZ1005. 4 The standard theory that held sway from the 10th century and into modern times was that the Zhouyi cantong qi was authored in the 2nd century C.E. by the semi-legendary alchemist Wei Boyang 魏伯陽 and transmitted to his disciples Xu Congshi 徐從事 and Chunyu Shutong 淳于叔通, though in the Tang period there were also theories maintaining that the text was somehow jointly authored by the three men, and that Wei Boyang was actually a disciple of either Xu Congshi or Chunyu Shutong. However, various modern scholars have cast serious doubt not only upon the authorship of Wei Boyang, but also on the notion that the received text could date as early as the 2nd century. Even though there is some evidence that a text known as the Cantong qi existed during the Han dynasty, that text was probably not the text that we have today and was likely not even concerned with alchemy. Fabrizio Pregadio estimates that the text "was composed in different stages, perhaps from the Han period onward, and did not reach a form substantially similar to the present one before ca. 450, and possibly one or even two centuries later." See (Pregadio 2011, pp. 1-27). 5 Here Yu Yan is alluding to a passage in the Zhouyi cantong qi that reads "After a thousand complete [readings] you are polished refined. After ten-thousand times you can see the gods." 千周粲彬彬兮 萬遍將可神明 (Fahui 9/5a).  (1194-1229?). While texts associated with the Nanzong are drawn upon most frequently by Yu Yan in his interpretations of the Zhouyi cantong qi, he also draws on other works, including especially those of the northern Quanzhen 全真 tradition. Apparently, in his understanding, the methods of the Nanzong and Quanzhen traditions were essentially the same.
Based on insights gained both from extensive reading of Neidan literature and his own subjective experiences, Yu Yan interprets the abstruse and opaque verses of the Zhouyi cantong qi in a way that now and again describes meditative practice and experience in an unusually concrete, detailed and vivid manner. While such a (relatively) accessible style of exposition becomes more common in Neidan texts of the late Ming period onward, it is still rather rare in materials of the Song and Yuan-thus the value of studying Yu Yan's Fahui. A full study of the Fahui promises to reveal to us in unparalleled clarity what Neidan practitioners of the 13th century underwent and experienced.
Of course, such a full study is not feasible within the length limitations of our essay. Here we shall focus in particular upon what Yu Yan had to say about the suspension of breathing and pulse, as well as the extraordinary inner sensations and visions that accompany it. As we shall see, Yu Yan maintains that these things come about by simply bringing body and mind to the depths of stillness; they are not instigated through deliberate procedures such as holding of breath, visualization, incantation, gulping air, swallowing saliva, etc. Through sheer inner calm and single-minded concentration, breathing and pulse are suspended while an inner qi 氣 is generated that surges and circulates the body, bringing forth ravishing sensations and strange visions. Yu Yan explains why the inner qi and the visions come to be generated, and why one should and can disregard the visions.
Yu Yan's descriptions and explanations regarding inner calm and its wondrous effects help shed light on the Neidan methods of the major traditions of his time (especially Nanzong and Quanzhen), revealing details that tended to be obscured in abstruse metaphor or reserved for oral transmission. One wonders whether, and to what degree, his descriptions of sensory and physical phenomena are based on what he himself experienced through practice. As will also be pointed out, certain key elements of Yu Yan's theories originate well before the Song and Yuan periods (when the major forms of Neidan emerged), and find precedent within texts dating as far back as the third or second centuries.

Calm Sitting and the Suspension of Breathing and Pulse
In the 9th juan 卷 of the Fahui, commenting on a phrase in the main text of the Zhouyi cantong qi that reads something like, "with the belly even, sit properly and let the warmth hang down" 腹齊正座 垂溫, 7 Yu Yan gives the following simple description of how to sit in meditation: Ziyang was his sobriquet (hao 號); Boduan was his personal name (ming 名). Similarly, the personal names of Xue Zixian and Chen Niwan are provided in the parentheses. 7 This phrase occurs within a section entitled "Song of the Tripod Vessel" (dingqi ge 鼎 器 歌), which when read in a straightforward manner seems to describe the apparatus used in laboratory alchemy. The phrase in question here is perhaps meant originally to refer to the "belly" of the tripod vessel and how it is to rest evenly and well-balanced as heat is applied to it. However, Yu Yan, who reads the Zhouyi cantong qi as a meditation text, naturally understands the "tripod vessel" to mean the adept's body.
If you close them completely, [your field of awareness] thereby becomes the ghost grotto in the black mountain. Your breath should enter the nose and penetrate the apertures and passages. You must not breathe coarsely. If you breathe coarsely, the fire will blaze. If the fire blazes, the medicine will fly. (Fahui 9/7b) Thus, you are to sit in a balanced posture, close your eyes part way, and breathe in a manner that is not "coarse". The eyes are left partly open so that you can stay alert; "the ghost grotto in the black mountain" is probably best understood as a condition where the mind has languished to where it is either unconscious or is vulnerable to delusions and fantasies. For the eyes to face the nose means perhaps that as you peer out of your half-closed eyelids, the tip of your nose is in your field of vision. The exact meaning of "the nose faces the navel" is harder to understand; but what this perhaps ultimately amounts to is that your attention is directed toward your navel, which in the Fahui, as in so many other Daoist texts, is the location where so many of the key phenomena are supposed to unfold. The breath goes into the nose and penetrates the various "apertures and passages" throughout the body. Your manner of breathing must not be "coarse"-in other words, it should be soft, deep and slow, rather than rapid and vigorous. To say that the "fire blazes" seems to mean that breathing in a rapid, gasping manner creates an excessive inner tension that somehow leads to the squandering of the vital energy that sustains life and can effect inner alchemical transformation-this is here referred to as "medicine" 藥, but is more often referred by Yu Yan as the "One qi" 一氣 or the "genuine qi" 真 氣. 8 A more straightforward description of how to breathe can be found in the Fahui's 6 th juan, where it states: 9 If a person can turn back the radiance and illuminate inwardly on this place while breathing out subtly and breathing in softly without interruption, spirit and qi will return to their root. [Your breathing] will gradually enter and gradually soften. It will gradually harmonize and gradually stabilize. After you have stabilized it for a long while there will no longer be any exhalation or inhalation. The medicine will thereby form on its own. (Fahui 6/17b) "This place" referred to here is what is described in the text right prior to this passage as "the root and source of the Great Elixir" 大丹之根源, "the homestead where the medicine is produced" 藥物所產 之鄉 or the "water" 水, which corresponds to the kan 坎 trigram and is located in the "north" 北. One may speculate here that "this place"-if it is in fact a concrete location in the body-10 is the kidneys (the organ that corresponds to the north, water and kan), or perhaps the lower Elixir Field located in 8 Qi 氣 is translated as "breath," only in cases where it clearly refers to air that is being breathed. In other instances it is left untranslated. The One qi or genuine qi is the vital energy of the eternal, ubiquitous Dao that has created the multiplicity of the universe out of an original Unity. Inner alchemy endeavors to retain, recover and activate this One qi, and to revert to the original state of Unity with the Dao. 9 The passage being commented on here reads, "The man is white, the woman is read. Metal and fire adhere to each other. When they adhere, the water is stable. Water is the beginning of the Five Phases." 男白女赤 金火相拘 拘則水定 水五行初 10 Some Neidan authors of the Southern Song and Yuan-such as Bai Yuchan, Chen Chongsu 陳沖素, Li Daochun 李道純, and Miao Shanshi 苗善時-steadfastly refused to identify any organ or location in the body as the "place" where the One qi (or "medicine," or "elixir") forms and emerges. The "place" (referred to by various terms such Single Aperture of the Mysterious Pass [xuanguan yiqiao 玄關一竅] or the Mysterious Female [xuanpin 玄牝]) as they describe it seems to exist on the metaphysical plane, or is a mental "place" or state of mind of complete calm and equilibrium. While Yu Yan disdained people (such as the proponents of sexual techniques) who interpreted Neidan terminology in crassly physical terms, he also disapproved of those who understood Neidan in exclusively metaphysical or psychological terms. Such people, in his view, wrongly construed the Way of the Golden Elixir as being the same thing as Chan Buddhist meditation, and unjustly disdained those who sought to extend their lives. In Fahui 6/12b, he states, " [They] think that [the Way of the] Golden Elixir is Chan Sect [Buddhist meditation]. Consequently they regard the original nature to be the Mysterious Female. They take the stirring of thought to be the emergence of the single yang. They regard the removal of perverse thoughts as being the advancement of fire. They snicker at the theories on prolonging life, and regard them as scenery beneath the skull." 認金丹 禪宗 遂以宗性玄牝 以念頭動處一陽生 以掃除妄念進火 而竊笑延命之說髑髏下光景 front of the kidneys and behind the navel in the lower abdomen (in Fahui 2/15a [quoted immediately below], Yu Yan describes how the One qi [i.e., the medicine] is produced and gathered in the Elixir Field). In any case, while directing your attention toward "this place", you are to breathe softly. As you continue to do so your breathing will become progressively even softer, and eventually gets to where there is (temporarily) no breathing occurring at all through the nose and/or mouth. Concurrently with this spirit and qi more and more enter and settle into "this place," which is their "root." A somewhat more complex explanation of how the belly gets filled with vital qi and how the suspension of breathing comes about, is found in the Fahui's second juan, in comments pertaining to the Zhouyi cantongqi passage that states, "Manage and enclose, subtly and secretly. Rouse and spread about the treasure." 管括微密 闓舒布 (Fahui 2/14b) Yu Yan explains: To "manage and enclose, subtly and secretly" [means to do as follows]: The eyes enclose their radiance, the ears congeal the sounds, the nose regulates the breathing, and the tongue seals in the breath. Sit properly with your legs folded together. Submerge your spirit and guard inwardly. Do not employ your mind for even the slightest bit on external things.
If your eyes do not look, your cloud-souls return to your liver. If your ears do not listen, your essence returns to your kidneys. If your tongue makes no sounds, your spirit returns to your heart. If your nose does not smell, your white-souls return to your lungs. If your four limbs do not move, your intention returns to your spleen. After this, your cloud-souls are in your liver, and do not leak through your eyes. Your white-souls are in your lungs, and do not leak through your nose. Your spirit is in your heart, and does not leak through your mouth. Your essence is in your kidneys, and does not leak through your ears. Your intention is in your spleen, and does not leak through the pores of your four limbs. All five of them do not leak.
Thereby essence, spirit, cloud-souls, white-souls and attention all meld together to become the One qi (emphasis added) and gather in the Elixir Field. When this single breathing [of the One qi] replaces [that of] the nose, your mind becomes dazed while the dragon and tiger thrust open the great road. Once it is opened, the nectar of the eight gems flows and circulates via the canal. (Fahui 2/14b-15a) Thus, by remaining completely quiet and still, disengaging the mind and senses from external things while breathing in a controlled manner, you ultimately accumulate qi in the Lower Elixir Field in the belly. (Elsewhere, Yu Yan compares this process to the cooking of rice, in which the pot is sealed firmly by a lid, so as to concentrate the heat inward; the eyes, ears and mouth of the meditation practitioner must similarly act as a "lid" that seals in the "genuine qi" 真氣 so that the Great Elixir can be completed. [See Fahui 6/21a-b]) 11 The premise here is that all mental, sensory and motor activity that engages you with the outside world amounts to an expenditure of life-sustaining qi. Particularly interesting here is the notion that when you move any part of your body, "intention" is directed toward that part of the body, and becomes liable to leakage through the pores of that part of the body. "Intention" is one among five entities-along with essence, spirit, cloud-souls and white-souls-that are respectively said to properly reside in the five viscera-spleen, kidneys, heart, liver and lungs. Although Yu Yan does not name his source here, the underlined portion in this passage matches word for word a passage in the preface of Jindan sibai zi 金丹四百字 (Four Hundred Characters on the Golden Elixir), 12 which is ascribed to Zhang Boduan 張伯端, but which in the view of Yu Yan (as stated in Xishang futan) was actually authored by Bai Yuchan 白玉蟾. 13 However, the original source text for this scheme aligning five psycho-sensory components with the viscera is perhaps the Heshanggong 河 上公 commentary to the Laozi, which dates likely to the Later Han dynasty (25-220). 14 There, in the gloss to the phrase "gushen busi" 15 谷神不死 (Laozi, chapter 6), we find the following comments: The character gu here means "to nurture". If people can nurture their spirits, they will not die. The "spirits" are the spirits of the five viscera. The liver stores the cloud-souls, the lungs store the white-souls, the heart stores the spirit, the spleen stores the attention, and the kidneys store the essence and the will. If the five viscera are all damaged, the five spirits will leave. (Laozi Heshanggong commentary, 1/5a) The scheme set forth in the Heshanggong commentary is thus largely the same as that set forth by Yu Yan, with the difference that the kidneys are allotted with not only essence, but also "will" (zhi 志). These entities that must be retained and nurtured in the five viscera are collectively referred to in the Heshanggong commentary as "five spirits". This description seems appropriate since they constitute the agents of certain sorts of mental functioning that lend consciousness and sensation to the body. Though "essence"-which is often equated to seminal fluid-may seem like an exception here, it really is not, since here it is considered as the agent that flows to the ears and enables you to hear things.
While Yu Yan probably himself would have had no objection to referring to them as "spirits", we can see that in his Fahui, the five entities become the One qi when retained and gathered in the Elixir Field. The line between spirit and qi is in fact a thin one; the subtle vital qi that needs to accumulate in the Elixir Field is constituted by the psychic agents that enable you think, talk, smell, hear and act. (An interesting and very early precedent to this notion of producing a single vital qi in the Elixir Field is to be found in the Xiandao jing顯道經 [ca. 3rd c.], 16 where one is told to call out the names of the spirits of the five viscera so as to make them gather in the Elixir Field and generate the vital qi). 17 This vital qi eventually begins to "breathe" (xi 息), and when it does so, it "replaces" (huan 換) the ordinary breathing of the nose; in other words, your ordinary breathing is suspended while the internal vital qi moves and circulates. The subsequent movements of vital qi are of a quite dramatic, extraordinary nature, whereby new internal conduits are opened up.
The notion that the new entity (here described as the "One qi") formed in the Elixir Field in the belly starts to take on a life of its own by "breathing" and moving about the body -while the adept ceases to breathe through the nose-finds precedent in ca. 8th-10th century texts on "Embryonic Breathing" (taixi 胎息). These texts describe how by calmly focusing one's attention and breathing on the Lower Elixir Field, spirit and qi converge there to form a "sacred embryo," which breathes on its own and circulates the body while the adept's own breathing is suspended. 18 12 DZ1081. 13 See Xishang futan 2/6b (Siku quanshu, vol. 1061, p. 614); (Baldrian-Hussein 2004). 14 Daode zhenjing zhu 道德真經註 (DZ682). On the dating of this text, see (De Meyer 2004). 15 If interpreted in the conventional manner, the phrase would translate into something like, "the spirit of the valley does not die. But according to the Heshanggong commentary's interpretation, it is better translated as "If you nurture your spirits, you will not die." 16 DZ862. 17 See (Eskildsen 2015, pp. 87-88). 18 The Embryonic Breathing texts in question are Taixi jing zhu 胎息經註 (DZ130), Changsheng taiyuan shenyong jing 長生胎元神 用經 (DZ1405), Taixi jingwei lun 胎息精微論 (DZ829), and Damo dashi zhushi liuxing neizhen miaoyong jue 達磨大師住世留形真 妙用訣 (In Yunji qiqian [DZ1032] 59/14b-18a). See (Eskildsen 2015, pp. 254-75).
Perhaps the Fahui's most lucid discussion on the internal breathing of the vital qi is found in its 3rd juan, in Yu Yan's comments pertaining to a passage of the Zhouyi cantong qi that reads, "Exhalation and inhalation enfold and nurture each other; when breathing is kept waiting they become husband and wife." (Fahui 3/15a) 呼吸相含育 佇息夫婦 Yu Yan starts out his comments to this passage by drawing a parallel between a certain sort of "respiration" carried out by the macrocosm (heaven and earth) and the internal respiration of the microcosm (the human body). What constitutes the "breathing of heaven and earth" 天地之呼吸 is the "rising of the yang and the descending of the yin" 陽升陰降; what he presumably has in mind is how hot air rises and cold air descends, or how moisture rises as warm vapor, and later comes back down as cool rain. It is because yin and yang come and go in this sort of "respiration" that heaven and earth are so long-lasting. Yu Yan thus reasons that people can be similarly long-lasting if they can internally emulate this cosmic manner of "breathing".
As for how this internal microcosmic breathing is supposed to work, Yu Yan quotes a passage from Xiao Tingzhi's 蕭廷芝 (fl. 1260) Jindan dacheng ji 金丹大成集 that states, "When exhaling it exits the heart and lungs, and when inhaling it enters the kidneys and liver." 呼出心與肺 吸入腎與肝 (Fahui 3/15a) 19 Yu Yan explains that, "This is the natural breathing of the One qi. It is not the breathing of the mouth and nose." 玆蓋一氣自然之呼吸 非口鼻之呼吸也 In other words, it is the circulation of the "One qi" that does not go in and out of the nose or mouth, but circulates between the inner organs. This circulatory movement is perhaps-more likely than not-understood to be synchronized with the ordinary respiration through the nose. Yu Yan's understanding is likely that when you exhale ordinary breath through the nose, the "One qi" emerges from the heart and lungs, and perhaps heads in the direction of the kidneys and liver when you inhale ordinary breath through the nose. (This theory of inner breathing also finds a very early-albeit slightly different-precedent in the Xiandao jing [ca. 3rd c.]. There is recorded a conversation where a certain interlocutor asks "Laozi" 老子, "Dao-qi emerges from the Elixir Field. What organs does it go in and out of?" 道氣生丹田 出入何藏 To this Laozi replies, "When you exhale, it enters the lungs and heart. When you inhale, it enters the kidneys and liver" 吁入 肺心 吸入腎肝.) 20 Yu Yan proceeds to discuss (quoting a couple of currently lesser-known, lost sources) 21 the importance of concentrating your attention on "the place where the Genuine Person breathes" 真人呼 吸處. This is located in the belly, in a place "facing the navel in its front and facing the kidneys in its back." 22 前對臍輪 後對腎 Yu Yan instructs the reader to practice as follows: If a person can empty the mind and concentrate the spirit, revert the radiance and internally illuminate the place where the Genuine Person breathes, going along with its ascending and descending, according with its natural process while keeping [attention on] it, in a short while the exhalations and inhalations will contain and nurture each other and abruptly come to a standstill. They thus become smashed together into a single piece, and combine to become husband and wife. (Fahui 3/15b) The method, then, is to calm and clear the mind, and concentrate on the special spot in the belly while allowing your breathing to occur naturally. What is meant by this is apparently both the inner breathing of the vital qi, and the ordinary breathing through the nose. The phenomenon described here in which the breathing comes to a standstill is presumably the same phenomenon described in the previous passage in which the breathing of the inner vital qi "replaces" the breathing of the ordinary breath through the nose. In other words, your ordinary breathing through the nose and/or mouth becomes suspended.
What happens from this point to the vital qi, on the other hand, can apparently be rather dramatic. The previous passage describes it as a state where "your mind becomes dazed," and during which "the dragon and tiger thrust open the great road," consequently bringing it about that "the nectar of the eight gems flows and circulates via the canal." Fortunately, what appears to be a much more concrete description of these same phenomena is to be found in the Fahui's 3rd juan, in Yu Yan's comments to the Zhouyi cantongqi passage that reads, "The golden sand enters the five inner [organs], and the fog scatters like wind and rain". 金砂入五 霧散若風雨 (Fahui 3/18a) Yu Yan comments on this as follows: This is the golden sand ascending the cauldron. It pierces through the two kidneys. Leading through the spine, it passes through path of the heart and enters the sea of marrow (brain). Thrusting through the acupuncture point of the lungs, it passes through the liver and spleen, and returns back to the [Lower] Elixir Field. When it is ascending, you feel as though clouds and mists are filling the four directions, and as though gusts of wind and rain are coming at you. You find yourself in a stupor as though you have just woken from a daytime dream. You feel refreshed as though a chronic illness has just left your body. Your subtle spirit darkly merges as though in the midst of the copulation of husband and wife. Your bones and flesh feel relaxed and harmonious as though you have just bathed. These are all actual experiences. These are not metaphors. (Fahui 3/18a) Yu Yan thus describes how the vital qi (described here as "golden sand") from the Elixir Field undertakes a circuit up and down the body, into the kidneys, up the spine, into the head and back down to the Elixir Field; in the process it passes through each of the five viscera. He also describes in very vivid and concrete terms how this makes you feel. Overall, the feeling certainly appears to be very good-pleasurable, even-and is compared to sexual intercourse, among other things.
Yet, it can also be said that your condition at this time is comparable to death, since your breathing is suspended. Yu Yan elsewhere indeed makes this comparison. In the Fahui's 4th juan, he comments on a passage of the Zhouyi cantong qi that reads, "Breath is exhausted and life is about to become extinct; it stops and dies, losing the white-souls and cloud-souls. 氣索命將絕 休死亡魂魄 (Fahui 4/11a) Regarding what is meant here by "death" Yu Yan explains as follows: The so-called "death" here is not death. At this time you return to your roots and restore your life. Your spirit is concentrated and your essence congeals. Your eight pulses 23 all stop and your exhalations and inhalations are all non-existent. The breath is exhausted, as though it has become extinct. After becoming extinct, it comes back to life. This is what the Shangqing 23 There is perhaps a mis-transcription here; the text perhaps ought to read "six" (liu) instead, since shortly later on Yu Yan speaks of the six pulses (see note below). The word "bamai" that appears here refers usually not to the vessels or pulse of the bloodstream, but rather to the "eight-meridians", which are eight special channels through which vital breath is said to flow. Among these meridians are included the ren (up the spine) and du (down the front of the torso) channels through which the vital breath is supposed to flow during the crucial stages of Neidan being described by Yu Yan, during which breathing and pulse get suspended. In other words, to say that the eight meridians become stagnant at this moment would be contradictory to the passages where Yu Yan describes the circulation of the vital breath.
ji refers to when it says, "At this time I have undergone a great death, and am now about to come to life." Oh! If you want to know the time when the great medicine is formed, it is when the six pulses all stop, and the breath does not move about. This sort of phenomenon, if you have not personally experienced it, how can you make yourself describe it in words! (Fahui 4/11a-b) Here it is maintained that not only your breathing gets suspended, but also your pulse. The "six pulses" (liumai 六脈) referred here are the six palpation points 24 on the wrists that a physician would touch and feel in order to diagnose your physical condition. If so, then, the condition really is a lot like temporarily dying. After experiencing "death" you also experience "resurrection." For the vast majority of us, who cannot recall ever experiencing death-much less resurrection-it is hard to fathom what exactly this would feel like. Indeed, Yu Yan-who perhaps had experienced in meditation the death-like condition of suspended breathing and pulse-says that it is an experience that is hard to comprehend or convey in words, especially if you have not personally undergone it.
The Shangqing ji that Yu Yan quotes in the above passage is a work by the Nanzong Patriarch Bai Yuchan. 25 Slightly earlier on in his comments Yu Yan also quotes a passage from Chen Niwan's (Bai Yuchan's teacher) Cuixu pian 翠虛篇 that reads, "Pretty soon the hundred vessels all return to their source; pulse stops and breath stops, and the elixir forms for the first time." 促將百脈盡歸源 脈住氣停 丹始結 26 Yu Yan thus presents us with evidence that these two Nanzong patriarchs also attested to the fact that breathing and pulse do get suspended when one is in the depths of meditation. He is also convinced that Wei Boyang wrote of the same phenomenon during the second century.

Inner Sensations and Visions
In the 6th juan of the Fahui we find Yu Yan discussing how the effects brought on by meditative practice can intensify with diligent and sustained practice. There, he comments on a passage of the Zhouyi cantong qi that reads, "Signs of proof naturally progress and change. Your mind must be focused and must not be left unrestrained." 證驗自推移 心專不縱 (Fahui 6/26) Yu Yan comments on this as follows: If in your training you have made three portions of effort, you will have three portions of signs of proof. If you have made ten portions of effort, you will have ten portions of signs of proof. If you are able to practice this diligently, without ceasing from morning till night, for up to 100 days, your exercise will become efficacious. Your two kidneys will feel like boiling water and your bladder will feel like burning fire. Your eyes will have a divine radiance, and your ears will hear holy sounds. Your nose will smell unusual fragrances, and there will be sweet fluids in your mouth. Your body will feel harmonious and lush. The signs of proof will progress along with the days. It is important that the mind remain dedicated and is not left unrestrained. This is because it is truly to be feared that before you have been able to completely illuminate the principles, and while in calm meditative absorption, in a state that is like a dream and yet not a dream, you might become taken in by devilish surroundings. (Fahui 6/26a-b) 24 Each wrist has a cun 寸, guan 關 and chi 尺 palpation points, making a total of six sections of six points. 25 The Shangqing ji is included in the large inner alchemical anthology, Xiuzhen shishu (DZ263).The statement in question can be found in a long poem entitled, "Kuaihuo ge" 快活歌 (Xiuzhen shishu 39/5a). This poem is also found in Haiqiong chuandao ji 海瓊傳導集 (DZ1309), 13a. 26 Cuixu pian (DZ1090), 10b-11a. The passage appears within the poem "Luofu Cuixu yin" 羅浮翠虛吟.
Yu Yan emphasizes here the need for diligent and sustained effort. Sensory and physical phenomena indicative of significant attainment ("signs of proof" 證驗) will only occur to a degree commensurate to the length and intensity of your practice. If the practice is diligently maintained for about 100 days, significant effects are supposed to come in the form of unusual, yet pleasant sensations, along with enhanced sensory acuity that enables you to see, hear, smell and taste things of a numinous nature. When this happens it is no time to become complacent or careless, because it is apparently at these stages that you become particularly liable to encounter "devilish surroundings" (mojing 魔 境). What this refers to are various sorts of visions that can distract you and undermine your progress.
Regarding what sorts of visions these may be, and how you ought to deal with them, Yu Yan quotes the following passage from a text entitled Xinxing jue 心性訣 (Lesson on the Mind and Nature) by a certain Ding Lingyang 丁靈陽: If in your stillness you press down upon yourself with profound effort, you may suddenly see Transcendents, Buddhas, ghosts, gods, or resplendent towers and terraces. When all sorts of objects of perception appear before your eyes, you absolutely must not give rise to thoughts, or to feelings of hatred or love. My teacher once said, "The inside of your consciousness is empty and wide open. Even though a thousand transformations and ten-thousand changes may occur in it, if your one mind does not waver, the ten-thousand evils will retreat by themselves. If the fire of the heart does not arise, spirit and qi will gather together, and child and mother will guard each other. Naturally water and fire will merge together. When water sees fire it will naturally turn to vapor and rise up, steaming and pervading all the passages and conduits. Naturally the hundred vessels will become well regulated, and your four extremities will become harmonious. If you diligently and carefully guard this, the Dao will naturally tally with you." (Fahui 6/26b-27a) The visions apparently tend to be of supernatural beings of both the holy and demonic variety. As is stated elsewhere in various other Daoist texts of other periods, 27 the way to deal with such visions is to simply stay calm and let the visions dissipate on their own. Here, as Ding Lingyang's teacher (whoever this is) explains it, your field of awareness in meditation is a wide-open vacuum from which any number and variety of images can spontaneously make an appearance; perhaps when the senses are withdrawn from external stimuli and the conscious mind is not purposely engaged in thinking or imagining, diverse contents of the subconscious mind become able to enter your consciousness. If your mind can remain calm and dispassionate despite all of this, you can proceed to where the key internal alchemical phenomena of spirit and qi can unfold in your body. These phenomena, it would appear, are the same-or at least something similar to-what Yu Yan describes in the previous passages. "Fire" here refers to spirit, or, in other words, to the functioning of the conscious mind. Its counterpart "water" refers to qi. For the heart not to "produce fire" means to not give rise to thoughts or feelings when confronted with visions. The coming together of water and fire most likely refers to the moment when spirit and qi come to be thoroughly concentrated in the Elixir Field. In the other passages we saw that once this happens breathing and pulse become suspended while the "One qi" undertakes a circuit through the kidneys, up the spine, into the head, and back down to the Elixir Field. The upward movement of the qi seems to be what is described here as the water rising as hot steam.
In the view of Yu Yan, it would appear that the visions are not caused by demonic beings that come from outside the practitioner's mind and body. In discussing the cause and source of visions, Yu Yan cites the statements of two texts, namely, Wang Qiyun's 王栖雲 Panshan yulu 盤山語錄, and the Guan Yinzi 關尹子. Wang Qiyun (Zhijin 志謹; 1178-1263) was an eminent northern Quanzhen master who received tutelage from Hao Datong 郝大通 and Qiu Chuji 丘處機, both of whom were among the top disciples of Quanzhen founder Wang Zhe. "Guan Yinzi" is the name of a Daoist philosophical text that had once circulated during or prior to the Former Han period, and which was attributed to Yin Xi 尹喜, Guardian of the Hangu Pass and disciple of Laozi. The version quoted by Yu Yan, however, is one that probably was written during the 12th century, and which had come to be held in high esteem within the Quanzhen tradition. 28 The passage quoted from Wang Qiyun's Panshan yulu reads as follows: People who engage in training experience many kinds of objects of perception when they are in the midst of stillness. These are all transformations wrought by your own cognitive spirit. They manifest themselves due to your stillness, and set out to entice the Lord of the Mind.
Have you not heard that a man of old has said [the following words?]: "Everything that has perceptual form is an illusion." Your mind needs to eliminate cognition. If the cognitive spirit is still there, it will conjure up forms and shapes. With heads of gods and faces of demons they will confuse the Lord of the Mind. If the Lord does not waver, and behaves as if it has not seen them even though it has, then its body is like empty space, with nothing to grasp or feel. Naturally, [the visions] will disappear and scatter. (Fahui 6/27a) 29 Here the generation of visions-all of which are actually hallucinations-is blamed on "cognition" (shi 識), or "the cognitive spirit" (shishen 識神), that is out to bring confusion to the "Lord of the Mind" (xinjun 心君). The "Lord of the Mind" here seems to refer to your subjective awareness and volition, which in meditation needs to just passively observe, without engaging in any active thinking. The problem is that the effects of cognitive activity that linger in your mind can frequently cause you to lapse into to active thinking. When the conscious mind is becoming still and is threatening to push all previously acquired ideas, memories and impressions out of its horizons, these mental contents take on a life of their own as tempting spirits to try to get the mind to react to them and consequently retain them.
Such, then, is the explanation for visions in meditation that Yu Yan adopts. But what about the visions or hallucinations that are experienced by people who are not meditating? Yu Yan addresses this matter by quoting the following passage from the Guan Yinzi: When people on ordinary days suddenly see extraordinary things with their eyes, this is always because they have coagulations of essence that cause them to do so. When people see extraordinary things on days when they are ill, this is always because their hearts bear grudges, which cause these [hallucinations]. If you understand that your mind can manifest being out of non-being, you will also understand that your mind can manifest non-being out of being. If you just do not believe in it, [the hallucination] will naturally not be spirit-like. Some would say "If the mind is already in confusion, how could it not believe [in the 28 See (Schmidt 2004). 29 In Panshan qiyun Wang zhenren yulu 盤山栖雲王真人語錄 (DZ1059), this passage appears on p. 21b. hallucination]?" I would respond to this by saying, "If a catcher of snakes does not fear snakes, he will also not fear snakes when he sees them in his dreams." Thus, the Yellow Emperor said, "The Dao has no demons and gods. Alone it goes, and alone it comes." (Fahui 6/27a-b) 30 The biggest problem posed before us in understanding this passage is the meaning of "coagulations" (jie 結) of "essence" (jing 精). At the very least, though, it would appear that the alleged source of the visions experienced by people on "ordinary" days (when they are in normal health) is an internal, physiological one. "Essence" here is probably best understood as seminal fluid and/or other fluids that nourishes the body (or can impregnate when administered outwardly) but which can somehow become blocked and caused to coagulate in a manner that is detrimental. Of course, the character jing in some contexts does refer to spiritual or spectral beings that inhabit the natural world, and it is possible to interpret the above passage as stating that invisible spectral forces in the outer world congeal to take on forms that are visible to ordinary people. However, judging from what appears to be the overall argument of the passage (that visions have their origins in the person that sees them, and can be calmly dismissed by anybody who understands this), it would appear more plausible to think that the author was speaking of "essence" of the physiological kind. Yet, in his view, the condition of this physiological essence can assert a direct impact on one's mental condition.
If even people who seem healthy can hallucinate as a result of subtle flaws in their physiology, it is perhaps natural that people who are visibly suffering from illness would have hallucinations. However, in regard to such cases, the Guan Yinzi lays the blame on unwholesome thoughts and feelings that are present in the patient's mind. In any case, however, the cause of the hallucinations is internal, not external; understanding your mind's (and body's) propensity to hallucinate also enables you to stop your hallucinations.
Having said this, though, further questions begin to occur. Are there any spirits out there that are not hallucinations? Gods and demons aside, do we ever perceive anything that is not to some extent a fabrication of our own minds? In the view of Mahayana Emptiness philosophy-which had deeply penetrated Daoism during the late Six Dynasties and early Tang periods-31 the answer to this latter question is "no", since everything that we know or perceive is only known or perceived in a manner that is constrained and skewed by our own cognitive limitations and perspectives. In light of this, the allegory of the snake-catcher's dream could be taken as meaning not only that you can calmly deal with hallucinations if you are aware of their subjective origin, but also that you can face all of life's situations with detached equanimity if you are aware that your delight or anguish over them is a mere result of your own skewed, limited perceptions.
So why, according to the "the Yellow Emperor" as quoted in the Guan Yinzi, does the Dao 道 "have no demons and spirits"? This would seem to be because the Dao, despite creating the phenomena that people regard and fear as demons and spirits, does not regard them as such. This is either because the Dao does not possess that sort of cognitive propensity, or because it recognizes the phenomena as its own fabrication, and thus harbors no awe toward them. Indeed, the Dao, being the creator of all phenomena, can carry on fearlessly as though it were all alone, with no hindrances or adversaries anywhere. The point here is certainly that we should similarly disregard the demons and spirits that we have ourselves fabricated in our hallucinations. But are we, like the Dao, also the authors of all the phenomena we know of; should we therefore fear nothing whatsoever? It is difficult to determine whether such was what the Guan Yinzi's author and/or Yu Yan had in mind here.

Conclusions
In the above discussion, an overview of the entire Neidan regimen leading to immortality as understood by Yu Yan was not attempted. This is due not only to length limitations for this essay, but also to the fact that the structure of the Fahui makes such an overview difficult. As a commentary to the Zhouyi cantong qi, it follows the structure of that text and attempts to interpret its abstruse statements in a manner applicable to Neidan meditation; as a result, it does not present a systematic exposition of a regimen that proceeds in sequence from the initial to final stages. What we have focused on in our discussion is Yu Yan's descriptions and explanations of what apparently occurs at the relatively early stages of the regimen, when the "One qi" is generated and activated from the Lower Elixir Field in the belly.
What the adept does to generate and activate this qi is to sit calmly and breathe softly while turning the mind and senses inward upon the belly. This causes the five psychic components that are essence, spirit, cloud-souls, white-souls and intention to remain intact respectively in the kidneys, heart, liver, lungs and spleen, and to eventually converge in the Lower Elixir Field to produce the "One qi." This qi takes on a life of its own and begins to breathe, and in doing so moves about between the heart, lungs, kidneys and liver, simultaneously and in conjunction with the respiration through the nose. Eventually, however, this inner respiration obviates and "replaces" the ordinary respiration of the nose, meaning that one's breathing goes into suspension. The underlying understanding here seems to be that the body's vital qi normally needs to be constantly replenished by breathing air through the nose or mouth, since we are constantly squandering it by engaging the outer world with our ears, mouths, eyes, noses, and limbs. Vital qi, when not squandered, can sustain the body without drawing upon qi from the outside.
While Yu Yan's exposition is based primarily on his reading of Neidan literature of the Song and Yuan periods, essential elements of his theory can be found in late Tang (ca. 8th-10th c.) Embryonic Breathing literature, the Xiandao jing (ca. 3rd c.), and the Heshanggong commentary to the Laozi (Later Han; 1st-2nd c.). The state wherein ordinary breathing is suspended while the body is sustained by "the natural breathing of the One qi," is to be regarded as a return to a natural, pristine state-that of the unborn child resting snugly in the mother's womb. Reverting to that state requires nothing more than calmly disengaging from the outside world.
The singular vital qi, however, not only sustains the body but can bring forth wondrous effects and transformations upon it. The qi surges through the spine, up to the brain, and circulates throughout the body, producing variously invigorating, stupefying, refreshing or pleasurable sensations. Not only one's breathing, but also one's pulse becomes suspended, meaning that one experiences a temporary death of sorts, followed by a resurrection. At this point one's cultivation of the singular qi has reached the point where it is said that the "great medicine" has formed. While one wonders here whether Yu Yan's vivid testimony comes from his own experiences, he does draw on the testimony of Nanzong luminaries Chen Nan and Bai Yuchan in asserting that the suspension of both breathing and pulse does occur and is indeed necessary.
As one continues further in one's practice, one enjoys more extraordinary inner sensations, as well as enhanced sensory acuity and mystical perception by which one sees, hears, tastes, and smells things of a holy, sublime nature. Unfortunately, however, one becomes afflicted increasingly with "devilish surroundings"-i.e., visions of a deluding, tempting nature. These, according to Yu Yan, have no objective reality whatsoever, and are mere hallucinations that will go away if one calmly dismisses them. Yu Yan here cites the authority of northern Quanzhen master Wang Zhijin, who maintained that such visions are mere illusions fashioned by one's own "cognitive spirit." Knowing the cause of hallucinations will not prevent one from having them; however-as pointed out in the passage quoted from the Guan Yinzi-it does enable one to recognize them for what they are, and to calmly dismiss them when they do occur. If it is to be understood that all of our attachments and anxieties in life are mere fantasies fashioned by our own cognitive limitations and selfish agendas (though Yu Yan does not explicitly argue this), perhaps we can calmly dismiss all of them as well.
Yu Yan's Fahui, despite lacking in sequential, systematic exposition, is a treasure trove rich in concrete, vivid descriptions of meditative practice and experience. Further analysis of it should certainly enable us to shed a great deal more light on what Neidan practice and experience consisted of during the Yuan period.

Conflicts of Interest:
The author declares no conflict of interest.