Taiji (philosophy) in the context of "Zhou Dunyi"

The bagua (Chinese: 八卦; pinyin: bāguà; lit. 'eight trigrams') is a set of symbols from China intended to illustrate the nature of reality as comprising mutually opposing forces reinforcing one another. Bagua is a group of trigrams—composed of three lines, each either "broken" or "unbroken", which represent yin and yang, respectively. Each line having two possible states allows for a total of 2 = 8 trigrams, whose early enumeration and characterization in China has had an effect on the history of Chinese philosophy and cosmology.

The trigrams are related to the divination practice as described within the I Ching and practiced as part of the Shang and Zhou state religion, as well as with the concepts of taiji and the five elements within traditional Chinese metaphysics. The trigrams have correspondences in astronomy, divination, meditation, astrology, geography, geomancy (feng shui), anatomy, decorative arts, the family, martial arts (particularly tai chi and baguazhang), Chinese medicine and elsewhere.

In Chinese philosophy, a taijitu (Chinese: 太極圖; pinyin: tàijítú; Wade–Giles: tʻai⁴chi²tʻu²) is a symbol or diagram (圖; tú) representing taiji (太極; tàijí; 'utmost extreme') in both its monist (wuji) and its dualist (yin and yang) forms. A taijitu in application provides a deductive and inductive theoretical model. Such a diagram was first introduced by Neo-Confucian philosopher Zhou Dunyi of the Song Dynasty in his Taijitu shuo (太極圖說).

The Fourth Daozang, a Taoist canon compiled in the 1440s CE during the Ming dynasty,has at least half a dozen variants of the taijitu. The two most similar are the Taiji Xiantiandao and wujitu (無極圖; wújítú) diagrams, both of which have been extensively studied since the Qing period for their possible connection with Zhou Dunyi's taijitu.

Taegeuk (Korean: 태극; Hanja: 太極, Korean pronunciation: [tʰɛgɯk̚]) is a Sino-Korean term meaning "supreme ultimate", although it can also be translated as "great polarity / duality / extremes". The term and its overall concept is derived from the Chinese Taiji, popularised in the west as the Yin and Yang. The symbol was chosen for the design of the Korean national flag in the 1880s. It substitutes the black and white color scheme often seen in most taijitu illustrations with blue and red, respectively, along with a horizontal separator, as opposed to vertical.

South Koreans commonly refer to their national flag as taegeuk-gi (태극기), where gi (기) means "flag" or "banner". This particular color-themed taegeuk symbol is typically associated with Korean traditions and represents balance in the universe; the red half represents positive cosmic forces, and the blue half represents the complementary or opposing, negative cosmic forces. It is also used in Korean shamanism, Confucianism, Taoism, and Buddhism.

In Chinese philosophy, wuji (simplified Chinese: 无极; traditional Chinese: 無極; lit. 'without roof/ridgepole', meaning 'without limit') originally referred to infinity. In Neo-Confucian cosmology, it came to mean the "primordial universe" prior to the "Supreme Ultimate" state of being.

Li (Chinese: 理; pinyin: lǐ) is a concept found in neo-Confucian Chinese philosophy. It refers to the underlying reason and order of nature as reflected in its organic forms.

It may be translated as "rational principle", "law", or "organisational rights". It was central to Zhu Xi's integration of Buddhism into Confucianism. Zhu Xi held that li, together with qi (氣: vital, material force), depend on each other to create structures of nature and matter. The sum of li is the Taiji.