The I Ching (?? pinyin yi jing) is the oldest of the Chinese classic texts. Alternative romanizations of the name include I Jing, Yi Ching, Yi King. Translations of its name into English include the “Book of Changes” or more accurately “Classic of Change". It describes an ancient system of cosmology and philosophy which is at the heart of Chinese cultural beliefs. The philosophy centres around the ideas of balance through opposites and acceptance of change. See the Philosophy section below for more.
The book - or a part of it - is also known as Zhou Yi (?? zhou yi; alternately Chou I), the “Changes of Zhou", in ancient Chinese literature which indicates the book was based on work from Zhou Dynasty. See the History section below for more.
In the Western cultures, it is known mostly as a system of divination.
Structure
The I Ching symbolism is embodied in a set of 64 abstract line arrangements called hexagrams (? gua). These are each composed of six stacked horizontal lines (? yao); each line is either Yang (unbroken, a solid line), or Yin (broken, an open line with a gap in the centre). With six such lines stacked from bottom to top in each hexagram, there are 26 or sixty-four possible combinations and thus sixty-four hexagrams.
Each hexagram is considered to be composed of two three-line arrangement called trigrams (? gua). There are 23, hence 8, possible trigrams.
Each hexagram represents a state, a process, a change happening at the present moment. When an hexagram is cast using one of the processes of Divination with I Ching, each of the lines may be indicated as moving or unmoving. Moving ("old", or “unstable") lines have a polarity in the process of reversal; a full divination will consider the hexagram that would result from the lines changing polarity.
The traditional methods for casting the hexagrams use biased random number generation procedures, so the 64 hexagrams are not equiprobable.
There are a few formal arrangements of the trigrams and hexagrams with a traditional context. The ba gua is a circular arrangement of the trigrams, traditionally printed on a mirror, or disk. Legend states that Fu Hsi found the ba gua on the scales of a tortoise’s back.
The King Wen sequence is considered the authoritative arrangement of the hexagrams.
Components of Hexagrams
The solid line represents yang, the masculine, creative principle. The open line represents yin, the feminine, receptive principle. These principles are also represented in a common circular symbol (?), known as taijitu (???), but more commonly known in the west as the yin-yang (??) diagram, expressing the idea of complementarity of changes: when Yang is at top, Yin is increasing, and the reverse.
In the following lists, the trigrams and hexagrams are represented using a common textual convention: horizontally from left to right, using ‘|’ for yang and ‘:’ for yin. Note, though, that the normal diagrammatic representation is to show the lines stacked vertically, from bottom to top (i.e. to visualize the actual trigrams or hexagrams, rotate the text counterclockwise 90).