In traditional Chinese culture and the East Asian cultural sphere, qi, also ki or chi in Wade–Giles romanization ( ), is believed to be a vital force forming part of any living entity. Literally meaning "vapor", "air", or "breath", the word qi is often translated as "vital energy", "vital force", "material energy", or simply as "energy". 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 in qi describe it as a vital force, the flow of which must be unimpeded for health. Qi is a pseudoscientific, unverified concept, and is unrelated to the concept of energy used in science (vital energy itself being an abandoned scientific notion). The historian of medicine in China Paul U. Unschuld adds that there "is no evidence of a concept of 'energy' – either in the strictly physical sense or even in the more colloquial sense – anywhere in Chinese medical theory." Linguistic aspects The cultural keyword qì is analyzable in terms of Chinese and Sino-Xenic pronunciations. Possible etymologies include the logographs , , and with various meanings ranging from "vapor" to "anger", and the English loanword qi or ch'i. Pronunciation and etymology The logograph is read with two Chinese pronunciations, the usual qì "air; vital energy" and the rare archaic xì "to present food" (later disambiguated with ). Pronunciations of in modern varieties of Chinese with standardized IPA equivalents include: Standard Chinese qì , Wu Chinese qi , Southern Min khì , Eastern Min ké , Standard Cantonese hei3 , and Hakka Chinese hi . Pronunciations of in Sino-Xenic borrowings include: Japanese ki, Korean gi, and Vietnamese khí. Reconstructions of the Middle Chinese pronunciation of 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 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". Characters In the East Asian languages, qì has three logographs: is the traditional Chinese character, Korean hanja, and Japanese kyūjitai ("old character form") kanji is the Japanese shinjitai ("new character form") kanji is the simplified Chinese character. In addition, qì is an uncommon character