All yogic and meditation-based traditions implicitly understand that "mind rides on wind (qi, prana, rlung, energy)" as the Tibetan Buddhists say. What most traditions fail to tease out sufficiently is the absolute necessity of cultivating and integrating qigong (pranayama, inner energy work) with meditation. For instance, the Yoga Sūtras of Patañjali (a prominent classic compiled before 400 CE), cleanly spells out that only mastery of pranayama gives access to meditation. Yet, if you read the details, most of the pranayama techniques given quickly lapse into increasingly intricate and prolonged patterns of breath retention—something suitable for seriously advanced yogis but not the majority of seekers.
With some unbiased study, you will find the same pattern in just about all traditions. That is, the ostensible teachings sketch a way forward but barely do justice for how to make the leap from beginner to adept. This stems from the universal need for all seekers to receive personal guidance and supervision from those further along the spiritual path. Spiritual tomes, of all traditions, simply aim to limn what needs to be done. Needed details have always been in the hands of lamas, gurus and teachers who provide first-hand instruction to students. Lacking direct contact with one's teacher, nothing much will ever happen for a spiritual practitioner regardless of how much she or he tries. Why?
In physics and engineering, this relates to a process known as resonance. For instance, when you twang a guitar string or tap a tuning fork, you get a fairly pure sound. If another, similar, guitar string or tuning fork lies in the vicinity it will also start to produce sound of similar pitch and quality. So, if two items are similar in make and fashion then one can trigger or key the other. It's the same in relationships. If two people are like peas in the pod then often one person will respond to the other even without the need for words to be spoken. The two are so comfortable and aware of each other that it's easy to pick up on subtle nuances. The same holds true for hanging out with a spiritual teacher, maven or whiz. In Hinduism, darshan (दर्शन, darśana) refers to the auspicious sighting of a deity or holy person. At heart, the magic of higher spiritual awareness rubs off on the devotee or student much like pixie dust sprinkling gently down from some benevolent fairy or angel. Sound loosey-goosey? Maybe, but the blessing is real and lasting.
So, genuine progress on the spiritual path requires the supervision and support of a spiritual teacher and, ideally, community of like-minded spiritual practitioners (sangha). This holds for all spiritual traditions. The rub here for most folks in the west stems from the simple dearth of advanced teachers (the ones with the pixie dust). Having ongoing access to such rare birds is even more of a pipe dream. The best most of us can hope for is to contact these teachers occasionally during workshops or retreats. But mostly, the spark of spiritual zeal depends upon association with other spiritual seekers in the local community and most importantly of all, your own personal efforts. Here's where Daoism saves the day.
Daoists recognized long ago (well over two thousand years; some accounts say four to five thousand years ago) that the fundamental quality of health or spiritual cultivation or anything for that matter is energy, which they named qi. Nowadays, qi can be understood as various gradations of biological electricity. At its simplest, this qi can be felt like warmth, tingling, pressure or a similar sensation. This happens just because electricity does affect tissues in the body so there are real, measurable responses as you sweep a hand (which has an electrical charge) over, say, your arm. The key to the entire epic of spiritual growth hinges on developing a felt sense of this qi and then gradually refining your awareness of its relation to your thoughts and consciousness.
From day one on the spiritual motorway to Light, Daoism is all about sensing and cultivating this qi. If you really want to progress and succeed, you should do likewise. Just add in qigong skills to your own spiritual tradition and practices. Get the okay from your teacher but by all means do learn to sense and control qi. Eventually, you learn to correlate qi with the prana of breathing practices and even later you learn to relate both qi and prana to the mind and deeper energies of Reality itself.
neidan and the genesis of daoist yoga
So, how does Daoism fit into the general scheme of yoga? Is it all yoga? Now, for a deeper answer you can read through a few books that will set Daoism in motion for you (Introducing Daoism, by Livia Kohn, is one good place to start). Or just, browse some entries on the web. There are plenty of reputable founts from which to draw. These can provide you some useful grit but the gist of what you should know up front rolls onto the table easily: Daoism started to form as a religion with the inception of the Celestial Masters school (2nd century CE) in Sichuan (far western China). This occurred several hundred years after the great classics, Dao De Jing (Tao Te Ching) (6th - 5th century BCE) and Zuangzi (Zhuang Zhou or Chuang Tzu) (4th - 3rd century BCE), had already arrived on the scene. These texts were—and still are—revered as the earliest bonafide streams of Daoist worldview.
From such simple beginnings, schools with a variety of names and philosophical bents began sprouting up across the country—to the east, in the north and to the south. Over the ensuing centuries, this variegated strand of loosely-knit confreres morphed and shape-shifted this way and that—sometimes in favor with the rulers and sometimes not. For a while (Tang dynasty, 7th - 10th centuries), the Daoist community enjoyed widespread prominence and finally hammered out the central tenets of its religion. In fact, these folks were so in favor with the mighty rulers and elite classes of the time that Daoism became the state religion. No mean feat, considering the competition—including Confucianism and Buddhism.
As you might guess, all good things have their time and place, so Daoist fortunes took an about-face as the dynasty collapsed. Since that golden era, this religious movement has shuffled and postured endlessly, aiming to fit in with the bureaucrats and cultural norms of the moment. However, the Daoist schools have never since gained such widespread political and social support.
Daoism today embodies many denominations but the two main ones are:
Orthodox Unity (Zhengyi, in Chinese) — This school claims a direct line of transmission from the very origins of Daoism way back with the Celestial Masters but modern scholarship suggests that’s wild hyperbole. Nevertheless, some links with the earliest Daoist motives, liturgy and social structures can be traced and have endured the many centuries of endless cultural and political unrest. Most non-monastic Daoist priests belong to this school—estimates suggest they number around several thousand worldwide.
Complete Perfection (Quanzhen, in Chinese) — Founded during the twelfth century in northern China this approach to living in harmony with the Dao shares many tenets with all other Daoist schools but distinguishes itself especially in two ways. First, it places great emphasis on self-restraint and control (including celibacy) and so most monastic Daoist priests camp out in these waters—estimates suggest they number a few thousand worldwide.
Second, and most importantly, Quanzhen places great emphasis on direct experience of higher mystical states. Of course, all esoteric traditions seek this. So, what’s different here? Notably, the theory goes that—along with the usual silent sitting to calm the mind—one needs some extra cosmic juice (qi, prana) to achieve full realization. So, higher knowledge gets empowered via the consistent practice of neidan (inner elixir; something roughly akin to tummo or kundalini)—after all, if you’re a nun or monk and have all that extra time on your hands, what else is there to do? Might as well visit the higher heavens, say what?