In traditional Chinese culture, qi or ch'i (Chinese: 气; pinyin: qì qì) is believed to be a vital force forming part of any living entity.^[4][5][6] Qi translates as "air" and figuratively as "material energy", "life force", or "energy flow".^[7] Qi is the central underlying principle in Chinese traditional medicine and in Chinese martial arts. The practice of cultivating and balancing qi is called qigong.

Believers of qi describe it as a vital energy, the flow of which must be balanced for health. Qi is a pseudoscientific, unverified concept,^[7][8] which has never been directly observed, and is unrelated to the concept of energy used in science^[9][10][11] (vital energy itself being an abandoned scientific notion).^[12]

The cultural keyword qì is analyzable in terms of Chinese and Sino-Xenic pronunciations. Possible etymologies include the logographs 氣, 气, and 気 with various meanings ranging from "vapor" to "anger", and the English loanword qi or ch'i.

The logograph 氣 is read with two Chinese pronunciations, the usual qì 氣 "air; vital energy" and the rare archaic xì 氣 "to present food" (later disambiguated with 餼).

Pronunciations of 氣 in modern varieties of Chinese with standardized IPA equivalents include: Standard Chinese qì /t͡ɕʰi˥˩/, Wu Chinese qi /t͡ɕʰi˧˦/, Southern Min khì /kʰi˨˩/, Eastern Min ké /kʰɛi˨˩˧/, Standard Cantonese hei3 /hei̯˧/, and Hakka Chinese hi /hi˥/.

Pronunciations of 氣 in Sino-Xenic borrowings include: Japanese ki, Korean gi, and Vietnamese khi.

Reconstructions of the Middle Chinese pronunciation of 氣 standardized to IPA transcription include: /kʰe̯iH/ (Bernard Karlgren), /kʰĭəiH/ (Wang Li), /kʰiəiH/ (Li Rong), /kʰɨjH/ (Edwin Pulleyblank), and /kʰɨiH/ (Zhengzhang Shangfang).

Reconstructions of the Old Chinese pronunciation of 氣 standardized to IPA transcription include: /*kʰɯds/ (Zhengzhang Shangfang) and /*C.qʰəp-s/ (William H. Baxter and Laurent Sagart).

The etymology of qì interconnects with Kharia kʰis "anger", Sora kissa "move with great effort", Khmer kʰɛs "strive after; endeavor", and Gyalrongic kʰɐs "anger".^[13]

In the East Asian languages, qì has three logographs:

In addition, qì 炁 is an uncommon character especially used in writing Daoist talismans. Historically, the word qì was generally written as 气 until the Han dynasty (206 BCE–220 CE), when it was replaced by the 氣 graph clarified with mǐ 米 "rice" indicating "steam (rising from rice as it cooks.)"

This primary logograph 气, the earliest written character for qì, consisted of three wavy horizontal lines seen in Shang dynasty (c. 1600–1046 BCE) oracle bone script, Zhou dynasty (1046–256 BCE) bronzeware script and large seal script, and Qin dynasty (221–206 BCE) small seal script. These oracle, bronze, and seal scripts logographs 气 were used in ancient times as a phonetic loan character to write qǐ 乞 "plead for; beg; ask" which did not have an early character.

The vast majority of Chinese characters are classified as radical-phonetic characters. Such characters combine a semantically suggestive "radical characters" with a phonetic element approximating ancient pronunciation. For example, the widely known word dào 道 "the Dao; the way" graphically combines the "walk" radical 辶 with a shǒu 首 "head" phonetic. Although the modern dào and shǒu pronunciations are dissimilar, the Old Chinese *lˤuʔ-s 道 and *l̥uʔ-s 首 were alike. The regular script character qì 氣 is unusual because qì 气 is both the "air radical" and the phonetic, with mǐ 米 "rice" semantically indicating "steam; vapor".

This qì 气 "air/gas radical" was only used in a few native Chinese characters like yīnyūn 氤氲 "thick mist/smoke", but was also used to create new scientific characters for gaseous chemical elements. Some examples are based on pronunciations in European languages: fú 氟 (with a fú 弗 phonetic) "fluorine" and nǎi 氖 (with a nǎi 乃 phonetic) "neon". Others are based on semantics: qīng 氫 (with a jīng 巠 phonetic, abbreviating qīng 輕 "light-weight") "hydrogen (the lightest element)" and lǜ 氯 (with a lù 彔 phonetic, abbreviating lǜ 綠 "green") "(greenish-yellow) chlorine".

Qì 氣 is the phonetic element in a few characters such as kài 愾 "hate" with the "heart-mind radical" 忄or 心, xì 熂 "set fire to weeds" with the "fire radical" 火, and xì 餼 "to present food" with the "food radical" 食.

The first Chinese dictionary of characters, the Shuowen Jiezi(121 CE) notes that the primary qì 气 is a pictographic character depicting 雲气 "cloudy vapors", and that the full 氣 combines 米 "rice" with the phonetic qi 气, meaning 饋客芻米 "present provisions to guests" (later disambiguated as xì 餼).

Qi is a polysemous word. The unabridged Chinese-Chinese character dictionary Hanyu Da Cidian defines it as "present food or provisions" for the xì pronunciation but also lists 23 meanings for the qì pronunciation.^[14] The modern ABC Chinese-English Comprehensive Dictionary, which enters xì 餼 "grain; animal feed; make a present of food", and a qì 氣 entry with seven translation equivalents for the noun, two for bound morphemes, and three equivalents for the verb.

Qi was an early Chinese loanword in English. It was romanized as k'i in Church Romanization in the early-19th century, as ch'i in Wade–Giles in the mid-19th century (sometimes misspelled chi omitting the apostrophe), and as qi in Pinyin in the mid-20th century. The Oxford English Dictionary entry for qi gives the pronunciation as IPA (tʃi), the etymology from Chinese qì "air; breath", and a definition of "The physical life-force postulated by certain Chinese philosophers; the material principle." It also gives eight usage examples, with the first recorded example of k'í in 1850 (The Chinese Repository),^[1] of ch'i in 1917 (The Encyclopaedia Sinica),^[2] and qi in 1971 (Felix Mann's Acupuncture)^[3]

References to concepts analogous to qi are found in many Asian belief systems. Philosophical conceptions of qi from the earliest records of Chinese philosophy (5th century BCE) correspond to Western notions of humours, the ancient Hindu yogic concept of prana. An early form of qi comes from the writings of the Chinese philosopher Mencius (4th century BCE).

The ancient Chinese described qi as "life force". They believed it permeated everything and linked their surroundings together. Qi was also linked to the flow of energy around and through the body, forming a cohesive functioning unit. By understanding the rhythm and flow of qi, they believed they could guide exercises and treatments to provide stability and longevity.

Although the concept has been important within many Chinese philosophies, over the centuries the descriptions of qi have varied and have sometimes been in conflict. Until China came into contact with Western scientific and philosophical ideas, the Chinese had not categorized all things in terms of matter and energy. Qi and li (理: "pattern") were 'fundamental' categories similar to matter and energy.

Fairly early on, some Chinese thinkers began to believe that there were different fractions of qi—the coarsest and heaviest fractions formed solids, lighter fractions formed liquids, and the most ethereal fractions were the "lifebreath" that animated living beings.^[17] Yuanqi is a notion of innate or prenatal qi which is distinguished from acquired qi that a person may develop over their lifetime.

The earliest texts that speak of qi give some indications of how the concept developed. In the Analects of Confucius qi could mean "breath".^[18] Combining it with the Chinese word for blood (making 血氣, xue–qi, blood and breath), the concept could be used to account for motivational characteristics:

The philosopher Mozi used the word qi to refer to noxious vapors that would eventually arise from a corpse were it not buried at a sufficient depth.^[19] He reported that early civilized humans learned how to live in houses to protect their qi from the moisture that troubled them when they lived in caves.^[19] He also associated maintaining one's qi with providing oneself with adequate nutrition.^[19] In regard to another kind of qi, he recorded how some people performed a kind of prognostication by observing qi (clouds) in the sky.^[19]

Mencius described a kind of qi that might be characterized as an individual's vital energies. This qi was necessary to activity and it could be controlled by a well-integrated willpower.^[20] When properly nurtured, this qi was said to be capable of extending beyond the human body to reach throughout the universe.^[20] It could also be augmented by means of careful exercise of one's moral capacities.^[20] On the other hand, the qi of an individual could be degraded by adverse external forces that succeed in operating on that individual.^[20]

Living things were not the only things believed to have qi. Zhuangzi indicated that wind is the qi of the Earth.^[21] Moreover, cosmic yin and yang "are the greatest of qi".^[21] He described qi as "issuing forth" and creating profound effects.^[21] He also said "Human beings are born [because of] the accumulation of qi. When it accumulates there is life. When it dissipates there is death... There is one qi that connects and pervades everything in the world."^[21]

Another passage traces life to intercourse between Heaven and Earth: "The highest Yin is the most restrained. The highest Yang is the most exuberant. The restrained comes forth from Heaven. The exuberant issues forth from Earth. The two intertwine and penetrate forming a harmony, and [as a result] things are born."^[21]

The Guanzi essay Neiye (Inward Training) is the oldest received writing on the subject of the cultivation of vapor [qi] and meditation techniques. The essay was probably composed at the Jixia Academy in Qi in the late fourth century B.C.^[22]

Xun Zi, another Confucian scholar of the Jixia Academy, followed in later years. At 9:69/127, Xun Zi says, "Fire and water have qi but do not have life. Grasses and trees have life but do not have perceptivity. Fowl and beasts have perceptivity but do not have yi (sense of right and wrong, duty, justice). Men have qi, life, perceptivity, and yi." Chinese people at such an early time had no concept of radiant energy, but they were aware that one can be heated by a campfire from a distance away from the fire. They accounted for this phenomenon by claiming "qi" radiated from fire. At 18:62/122, he also uses "qi" to refer to the vital forces of the body that decline with advanced age.

Among the animals, the gibbon and the crane were considered experts at inhaling the qi. The Confucian scholar Dong Zhongshu (ca. 150 BC) wrote in Luxuriant Dew of the Spring and Autumn Annals:^[23] "The gibbon resembles a macaque, but he is larger, and his color is black. His forearms being long, he lives eight hundred years, because he is expert in controlling his breathing." ("猿似猴。大而黑。長前臂。所以壽八百。好引氣也。")

Later, the syncretic text assembled under the direction of Liu An, the Huai Nan Zi, or "Masters of Huainan", has a passage that presages most of what is given greater detail by the Neo-Confucians:

The Huangdi Neijing ("The Yellow Emperor's Classic of Medicine", circa 2nd century BCE) is historically credited with first establishing the pathways, called meridians, through which qi circulates in the human body.^[24][25][26]

In traditional Chinese medicine, symptoms of various illnesses are believed to be either the product of disrupted, blocked, and unbalanced qi movement through meridians or deficiencies and imbalances of qi in the Zang Fu organs.^[26] Traditional Chinese medicine often seeks to relieve these imbalances by adjusting the circulation of qi using a variety of techniques including herbology, food therapy, physical training regimens (qigong, t'ai chi ch'uan, and other martial arts training),^[27] moxibustion, tui na, or acupuncture.^{[26] []}

The nomenclature of Qi in the human body is different depending on its sources, roles, and locations.^[28] For sources there is a difference between so-called "Primordial Qi" (acquired at birth from one's parents) and Qi acquired throughout one's life.^[28] Or again Chinese medicine differentiates between Qi acquired from the air we breathe (so called "Clean Air") and Qi acquired from food and drinks (so-called "Grain Qi"). Looking at roles Qi is divided into "Defensive Qi" and "Nutritive Qi".^[28] Defensive Qi's role is to defend the body against invasions while Nutritive Qi's role is to provide sustenance for the body. Lastly, looking at locations, Qi is also named after the Zang-Fu organ or the Meridian in which it resides:^[28] "Liver Qi", "Spleen Qi", etc.

A qi field (chu-chong) refers to the cultivation of an energy field by a group, typically for healing or other benevolent purposes. A qi field is believed to be produced by visualization and affirmation. They are an important component of Wisdom Healing'Qigong (Zhineng Qigong), founded by Grandmaster Ming Pang.^[29][30][31]

Concepts similar to qi can be found in many cultures.

Prana in Hinduism and Indian culture, chi in the Igbo religion, pneuma in ancient Greece, mana in Hawaiian culture, lüng in Tibetan Buddhism, manitou in the culture of the indigenous peoples of the Americas. In Western philosophy, notions of energeia, élan vital, or vitalism are purported to be similar.^[32]

Some elements of the qi concept can be found in the term 'energy' when used in the context of various esoteric forms of spirituality and alternative medicine.

Qi is a non-scientific, unverifiable concept.^[7] A 1997 consensus statement on acupuncture by the United States National Institutes of Health noted that concepts such as qi "are difficult to reconcile with contemporary biomedical information".^[33]

The 2014 Skeptoid podcast episode titled "Your Body's Alleged Energy Fields" related a Reiki practitioner's report of what was happening as she passed her hands over a subject's body:

Evaluating these claims, author and scientific skeptic Brian Dunning reported:

The traditional Chinese art of geomancy, the placement and arrangement of space called feng shui, is based on calculating the balance of qi, interactions between the five elements, yin and yang, and other factors. The retention or dissipation of qi is believed to affect the health, wealth, energy level, luck, and many other aspects of the occupants. Attributes of each item in a space affect the flow of qi by slowing it down, redirecting it or accelerating it. This is said to influence the energy level of the occupants.

One use for a luopan is to detect the flow of qi.^[34] The quality of qi may rise and fall over time. Feng shui with a compass might be considered a form of divination that assesses the quality of the local environment.

Qìgōng (气功 or 氣功) involves coordinated breathing, movement, and awareness. It is traditionally viewed as a practice to cultivate and balance qi. With roots in traditional Chinese medicine, philosophy and martial arts, qigong is now practiced worldwide for exercise, healing, meditation, and training for martial arts. Typically a qigong practice involves rhythmic breathing, slow and stylized movement, a mindful state, and visualization of guiding qi.^[35][36][37]

Qi is a didactic concept in many Chinese, Korean and Japanese martial arts. Martial qigong is a feature of both internal and external training systems in China^[38] and other East Asian cultures.^[39] The most notable of the qi-focused "internal" force (jin) martial arts are Baguazhang, Xing Yi Quan, T'ai Chi Ch'uan, Southern Praying Mantis, Snake Kung Fu, Southern Dragon Kung Fu, Aikido, Kendo, Hapkido, Aikijujutsu, Luohan Quan, and Liu He Ba Fa.

Demonstrations of qi or ki are popular in some martial arts and may include the unraisable body, the unbendable arm, and other feats of power. Some of these feats can alternatively be explained using biomechanics and physics.^[40]

Acupuncture is a part of traditional Chinese medicine that involves insertion of needles into superficial structures of the body (skin, subcutaneous tissue, muscles) at acupuncture points to balance the flow of qi. This is often accompanied by moxibustion, a treatment that involves burning mugwort on or near the skin at an acupuncture point.