This is also known as the Later Eight Trigrams.Shuo Gua reads，"Qian is(the symbol of)heaven，and hence has the appellation of father.Kun is(the symbol of)earth，and hence has the appellation of mother."Zhen，Kan，Gen are three sons while Xun，Li，Dui，three daughters.Three sons are all represented by Yang trigrams and three daughters，Yin trigrams.The three yang trigrams have three Yang Yao"s and six Yin Yao"s in all.Thus，"In a Yang trigram，Yin Yao"s are in majority."On the other hand，the three Yin trigrams have three Yin Yao"s and six Yang Yao"s in all.Therefore，"In a Yin hexagram，Yang Yao"s are in majority."Three sons and three daughters are in harmonious counterpart，indicating that the unity of opposites between yin and Yang，hardness and softness derived all things.
十四、文王八卦方位图
即《后天八卦方位图》。邵雍所传。用释《说卦》“帝出乎震”一节所示八卦方位。朱子云：“邵子曰：此文王八卦，乃入用之位，后天之学也”。以震兑离坎代表东西南北，称四正卦，余为“四隅卦”。亦称“帝出乎震图”。古代天文仪象的设置以此方位为准。XIV.Diagram of Eight Trigrams Bearings by King Wen
This is also known as Later Arrangement of Eight Trigrams by King Wen，which was passed down by Shao Yong for explaining the chapter of"God comes forth in Zhen"in Shuo Gua.That is a chapter showing the bearings of eight trigrams.Zhu Zi said，"Shao Zi said that this arrangement by King Wen was a later knowledge for application to bearings".What uses Zhen，Dui，Li，Kan to represent east，west，south，north is called"Si Zheng(four positive directions)Trigrams"，while the rest"Si Yu(four oblique directions)Trigrams".It is also called Diagram of"God comes forth in Zhen"，and was used as a criterion in ancient astronomy for bearings.
十五、卦气图（七十二候图）
取十二辟卦以表述一年12月气候变化。创自西汉孟喜，传自京房。以坎、离、震、兑为四正卦，表四时，其24爻代表24节；以十二辟卦代表12月，其72爻代表72候。概括了古代天文、历法、物候知识，显示四时循环周期，及人天统一思想。
XV.Gua Qi Tu(Diagram of 72 Pentads)
Taking 12 Pi(pioneering)hexagrams as a formulation of weather changes of the 12 months in a year，this was a creation of Meng Xi of Western Han Dynasty(206B.C.—A.D.24)，and passed down by Jing Fang.In this diagram，Kan，Li，Zhen，Dui represent Si Zheng hexagrams，indicating four seasons，the 24 Yao"s in the 4 hexagrams represent 24 solar terms.The 12 Pi hexagrams represent 12 months，and their 72 Yao"s represent 72 pentads.This diagram generalizes ancient astronomy，calendar and phenological knowledge as well as denotes the recurrence cycle of the four seasons and the thought of heaven-human unification.
十六、十二消息卦图（二十四节图）
此卦气图的组成部分，以十二辟卦代表十二月阴阳消长之节律，四正卦的二十四爻代表一年二十四节，复卦代表冬至一阳生，从此阳气日长，阴气渐消；姤卦代表夏至一阴生，从此阴气日长，阳气日消。四季阴阳消长呈渐进过程，周而复始，对农业生产及人类养生均有指导意义。
XVI.Diagram of 12 Xiao Xi Hexagrams(Diagram of 24 Solar Terms)
This is a component part of Gua Qi Tu.It indicates the rhythm of the coming and going of Yin and Yang of 12 months as represented by the 12 Pi hexagrams.Fu Hexagram symbolizes the coming into being of one Yang(Yao)at Winter Solstice，and from this time on，Yang grows daily and Yin diminishes；Gou Hexagram symbolizes the coming into being of one Yin(Yao)at Summer Solstice，and from this time on，Yin grows daily while Yang diminishes.The growth and diminishment of Yin and Yang in the four seasons are in gradual process，going round and beginning again.It has a guiding significance both in agricultural production and in human regimen.
十七、月体纳甲图
月体纳甲说，乃卦气说的一种形式。将道家内丹理论同月亮盈亏、四时变化相联系，以便掌握自然法则。置坎离于中宫，指“日月为易，刚柔相当”，表示月体凭日照而发光。震表示一阳已生，月起于西方；巽表示一阴已萌，亦配于西方。上弦月在南方，兑乃二阳之象；下弦月也在南方，艮乃二阴之象。北方不见月光，表示乾消坤藏。一月之中月亮盈亏变化过程，一览无余。
XVII.Na Jia Tu of the Moon
Na Jia theory of the moon is one of the forms of Gua Qi theory.It combines the theory of Taoist Pill for Immortality with the wax and wane of the moon，and the change of the four seasons，with the purpose of mastering the natural law.Putting Kan and Li at the central chamber，it regards"sun and moon as in alternation，and，hardness and softness as in balance".It indicates that the illumination of the moon relies on the sunshine.Zhen indicates the coming into being of one Yang Yao，thus the moon rises from the west；Xun indicates the coming into being of one Yin Yao，thus the moon rises from the west；Xun indicates the coming into being of one Yin Yao，also in the west.The first quarter of the moon is in the south，and Dui has two Yang Yao；the last quarter of the moon is also in the south，and Gen has two Yang Yao.There is no moon light in the north.this is an indication of the diminishment of Qian and concealment of Kun.The process of the wax and wane of the moon in a month can be seen at a glance and all clearly.
十八、爻辰图
《隋书？律历志》论历法同卦象之关系云“悬象著明，莫大于二曜；气序循复，无信于四时，……乃至阴阳迭用，刚柔相摩，四象即陈，八卦成列”，足见创历之初衷。爻辰乃以乾坤十二爻对应于十二月（支），将28宿之四象，对应于四方。地支按顺时针方向排列，28宿按反时针方向排列。子、午、卯、酉对应于虚、星、房、昴。乾坤十二爻交错排列，显示阴阳二气之对立、转化是星移斗转的原因。
XVIII.Yao Chen
(time designated by Yao"s)Tu
In dealing with the relation between calendar and hexagram，Lu Li Zhi in Sui Book writes，"The two illuminations of the sun and the moon are brightest in the sky；the four seasons are the most exact in orderly cycles...up to the overlap of Yin and Yang；hardness and softness stroke each other；Four Symbols exhibited，hexagrams are inarray."Here the original intention of calendar-making is clearly seen.Yao Chen takes the 12 Yao"s of Qian and Kun to correspond the 12 months(Earthly Branches).It also takes the 28 Su"s(lunar mansions)in Four Symbols to correspond the four directions.
The Earthly Branches are arranged in the clockwise order，while the 28 Su"s are in a reversed order.Zi，Wu，Mao，You are in the same directions as Xu，Xing，Fang，Mao.The 12 Yao"s of Qian and Kun are arranged in a crisscross way，showing Yin weather and Yang weather are opposite to each other，and their conversion is the cause of the change of stars in their positions.
十九、纳音图（“三分损益”图）
汉代以来，律、历并称。乐律与历法，均与易学关系密切。乐律学借用易卦象数以表征律吕损益法则。古乐中的十二律制，乃将一个八度音阶分为十二个不完全相等的半音，相当于今之12调。12律中，6阳律，以乾卦6爻代表；6阴吕，以坤卦6爻代表。六律与六吕由低到高依次排列，以“三分损益”法标算十二律管的不同长度，是古人行之有效的定律方法。
XIX.Na Yin Tu
