The I Ching, "Yijing(易经)", Classic of Changes or Book of Changes; also called "Zhouyi(周易)", The changes of the Zhou, is one of the oldest of the Chinese classic texts. The book is a symbol system used to identify order in random events. The text describes an ancient system of cosmology and philosophy that is intrinsic to ancient Chinese cultural beliefs. The cosmology centres on the ideas of the dynamic balance of opposites, the evolution of events as a process, and acceptance of the inevitability of change.
 

The Book of Changes is the most commented book of the old classics, said to be a composition of the mythical ruler Fuxi 伏羲, King Wen of Zhou 周文王, Duke Dan of Zhou 周公旦 and even Confucius. But instead, we can divide the text in the "original" listing of the 64 hexagrams and their respective line statements and the later "wing" commentaries. The main part with the listings can also be called "Changes of the Zhou", because it is the Zhou people's manual for the divination with milfoil stalks (shi 蓍). The former dynasty, the Shang 商, instead used heat crackings on oracle bones to divine. Its modern shape is very near to the original that must have been composed during the late Western Zhou Dynasty 西周.

Each of the hexagrams is composed of two of the Eight Trigrams (bagua 八卦). Each hexagram is named after its main fortune character, commented by a short statement (guaci 卦辭). Every single line of it, broken or solid (called "six" liu 六 and "nine" jiu 九 or "female" yin 陰 and "male" yang 陽), is commented by a line statement (yaoci 爻辭). The statements begin from bottom to top, counting as "beginning" (chu 初), two, three, four, five and "upper" (shang 上). The sequence of the 64 Hexagrams was not always the same. The commentary is very abstract and made room for occult prognostication, numerological and cosmological speculation and political and moral philosophizing during the Han Dynasty 漢 and the Song Dynasty 宋.
 

The ten "Wing Commentaries" (Shiyi 十翼) are products of the Han Dynasty and interprete the hexagram and its statements in a lexicological, symbolistic and philosophical way.
 

The important commentaries are that of Han time Kong Yingda 孔穎達, the Tang period 唐 scholar Lu Deming 陸德明 and the Song Dynasty Neo-Confucian Zhu Xi 朱熹. Still the best western translation is that of James Legge and the German one by Richard Wilhelm.
 

The Eight Trigrams (Bagua 八卦) are:

Qian 乾 (the Creative; Heaven)

Kun 坤 (the Receptive; Earth)

Kan 坎 (the Perilous Pit; Water)

Li 離 (the Clinging; Fire)

Zhen 震 (Exciting Power; Thunder)

Gen 艮 (Arresting Movement; Mountain)

Xun 巽 (Gentle Penetration; Wind)

Dui 兌 (Joy and Pleasure; Swamp)

The 64 Hexagrams:

First series 上經1 乾 Qian The Creative

2 坤 Kun The Receptive,Resting in Firmness

3 屯 Tun Initial Difficulty

4 蒙 Meng Youthful Folly, Obscurity

5 需 Xu Waiting, Nourishment

6 訟 Song Conflict

7 師 Shi The Army, Group Action

8 比 BiHolding Together, Union

9 小畜 Xiaoxu The Taming Force, Small Restraint

10 履 Lü Treading Carefully

11 泰 Tai Peace

12 否 Pi Stagnation

13 同人 Tongren Union of Men

14 大有 Dayou Great Possession, Abundance

15 謙 Qian Modesty

16 豫 Yu Harmony, Joy, Enthusiasm

17 隨 Sui Following

18 蠱 Gu Arresting Decay

19 臨 Lin Approach, Advance

20 觀 Guan Contemplation

21 噬嗑 Shihe Biting Through

22 賁 Bi Adornment

23 剝 Bo Falling Apart

24 複 Fu Returning

25 無妄 Wuwang Correctness, Innocence

26 大畜 Daxu The Great Taming Force

27 頤 Yi Correctness, Innocence

28 大過 Daguo Excess

29 坎 Kan The Perilous Pit

30 離 Li The Clinging; Brightness

Second series 下經

31 咸 Xian Influence

32 恆 Heng Preseverance, Duration

33 遯 Dun Retreat

34 大壯 Dazhuang The Power of the Great

35 晉 Jin Progress

36 明夷 Mingyi Darkening of the Light; Intelligence Wounded

37 家人 Jiaren The Family

38 睽 Kui Disunion, Mutual Alienation

39 蹇 Jian Arresting Movement

40 解 Jie Removing Obstacles

41 損 Sun Decrease

42 益 Yi Increase

43 夬 Guai Removing Obstruction, Breaking Through

44 姤 Gou Encountring

45 萃 Cui Gathering Together

46 升 Sheng Ascending

47 困 Kun Oppression

48 井 Jing A Well

49 革 Ge Revolution

50 鼎 Ding The Cauldron

51 震 Zhen Thunder, Exciting Power

52 艮 Gen Mountain, Arresting Movement

53 漸 Jian Gradual Progress, Growth

54 歸妹 Guimei The Marrying Maiden; Propriety

55 豐 Feng Abundance, Prosperity

56 旅 Lü Traveling Stranger

57 巽 Xun Gentle Penetration

58 兌 Dui Joy, Pleasure

59 渙 Huan Dispersion

60 節 Jie Regulation, Restraining

61 中孚 Zhongfu Inmost Sincerity

62 小過 Xiaoguo Small Excesses

63 既濟 Jiji Completion

64 未濟 Weiji Before Completion