What is the Bagua 八卦？

The Eight Trigrams (Bagua), originally eight diagrams in I Ching (Zhouyi), are composed of two symbols: "—" and "--". The former is called a yang line (yao), and the latter a yin line (yao). By combining yang and yin lines in groups of three, eight combinations can be formed, which are the Eight Trigrams, also known as the "Eight Fundamental Trigrams". According to the order of the innate (xiantian) trigram arrangement, the Eight Trigrams are: Qian (1) 乾一, Dui (2)兑二, Li (3)离三, Zhen (4)震四, Xun (5)巽五, Kan (6)坎六, Gen (7)艮七, and Kun (8)坤八 (see the table below).

The Eight Trigrams can also be divided into yin and yang: Qian, Kan, Gen, and Zhen are yang trigrams, while Xun, Li, Kun, and Dui are yin trigrams. To facilitate memorizing the Eight Trigrams, Zhu Xi, a great Confucian scholar in the Song Dynasty, created the Song of Images of the Eight Trigrams in his renowned work on I Ching—Original Meaning of Zhouyi. The opening verses of the song are: "Qian is three unbroken lines; Kun is six broken parts; Zhen is like an upturned basin; Gen is like an overturned bowl; Li has a hollow in the middle; Kan is full in the middle; Dui has a gap on top; Xun has a break at the bottom."