Taiji Above and Below explained as Heaven and Earth (太極上下名天地) by Yáng​ Bān​hóu​ (楊班侯)

太極進退不已功

四手上下分天地，採列肘靠有由去。
採天靠地相應求，何患上下不既濟!
若使挒肘習遠離，迷了乾坤遺歎惜。
此說亦明天地盤，進用肘挒歸人字。

楊班侯

"Differentiating the four hands above below are like heaven and earth; pluck, split, elbow and bump have their source in this separation.
If pluck from heaven and bump from earth correspond and look for each other; one should not worry if above and below support each other!
If one creates the habit of using split and elbow separately, one will lament the unbalance between heaven and earth.
This also explains the circles of heaven and earth; to advance in the application of split and elbow one should return to the word “man”."

Based on the translation by Yang Jwing Ming (楊俊敏) presented in the book Tai Chi Secrets of the Yang Style (太極拳楊氏先哲秘要)

Quiescence (清) by Dài Běnxiào (戴本孝​)​

Féng​ Zhèng​bǎo​ (馮正寳) demonstrating Xíngyìquán (形意拳)

Thirty-sixth Secret Song (歌訣三十六) from the The Thirty-Six Songs of Baguazhang (八卦掌三十六歌) Trigésima Sexta Canção Secreta (歌訣三十六) das Trinta e Seis Canções do Bāguàzhăng (八卦掌三十六歌)

歌訣三十六

用時最要是精神，
精神煥發耳目真，
任憑他人飛燕手，
蟻鳴我聽虎龍吟。

"When in application the key is vitality.
When one is glowing with health and vigor, all senses are alert.
It does not matter if the opponent’s hands are fast like a flying swallow,
The shout of an ant is like a tiger’s roaring or a dragon hissing to my ears."

Based on the translations by Yang Jwing Ming (楊俊敏) and Liang Shou You (梁守渝) in "Baguazhang - Theory and Applications" (峨嵋八卦掌) and by Frank Allen and Tina Chunna Zhang in "The Whirling Circles of Ba Gua Zhang"

Upright (正) from Foundation (基礎)Centro (中) de Fundamentos (基礎)

正

正者，姿勢端正。每一姿勢，務宜端正，而忌偏斜。然各種姿勢，各不相同，或仰，或俯，或伸，或屈，非盡中正。是以其發勁，及其用意之方向，而求其重心。蓋重心為全體樞紐。重心立，則開合靈活自如，重心不立，則開合失其關鍵。如車軸為車輪之樞紐，若使車軸置於偏斜，而不适於車身之重心處，則車輪轉動，進退失其效用矣。故拳架之姿勢，務求正确，則重心平穩，要不自牽扯其重心，而辨別虛實也。

"Upright means that the postures are correct. It means that every posture should be appropriate and upright, no posture should be given up and slant. Differente types of postures exist that have nothing in common with each other, they face upward, look down, extend, bend, at the end not centered and upright. The emission of Jin and the direction of the intention request the weight center. This is because the weight center is the main hinge of the entire body. Once the weight center is established, then opening and closing are nimble and unconstrained; if it is not established, opening and closing will miss its pivotal point. It is like the axle, who is the major hinge of the wheel; if it is out of alignement and not located at the weight center of the car, then the wheels with turn back and forth without being effective. This is why the frame of the boxing is the posture, it is important that it is correct so the weight center is steady; otherwise the weight center will be shifted and it will be impossible to differentiate the insubstantial and the substantial."

By Wú Gōngzǎo (吳公藻), based on the translation by by Yang Jwing Ming (楊俊敏) presented in the book Tai Chi Secrets of the Wu Style (太極拳吳氏先哲秘要).

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De Wú Gōngzǎo (吳公藻), baseado na tradução de Yang Jwing Ming (楊俊敏) apresentada no livro Tai Chi Secrets of the Wu Style (太極拳吳氏先哲秘要).

Baguazhang - Theory and Applications

As far as a Martial Art goes, Bāguàzhăng (八卦掌) seems to me the least likely to be treated on a book format. The rich and varied traditions, styles and approaches make a pure programatic book - as the ones usually seen for Tàijíquán (太極拳) - look very partial. In particular for a beginner like me, it is difficult to identify what are the good entry points.
This book overcomes these difficulties. Even if the technical overview is related to Swimming Body Baguazhang, a specific tradition, the content is laid out in a way that the western beginner can follow. And as any book on martial arts, it has to be approached as a support for the practice. The main use I have for this book is as a reference. The chapters on The Essence of Baguazhang and Training Concepts are extremely useful to frame the instruction received in the regular practice. It is really a companion book for the Baguazhang beginner.

Excerpt from Man in the World, Associated with other Men (人間世) in Zhuāng zi (莊子)

山木自寇也，膏火自煎也。桂可食，故伐之；漆可用，故割之。人皆知有用之用，而莫知無用之用也。

莊子

"The mountain by its trees weakens itself. The grease which ministers to the fire fries itself. The cinnamon tree can be eaten, and therefore it is cut down. The varnish tree is useful, and therefore incisions are made in it. All men know the advantage of being useful, but no one knows the advantage of being useless. "

Unless noted otherwise, all quotations of classical texts and accompanying translations come from the Chinese Text Project

Taiji Endless Workings of Advancing and Retreating (太極進退不已功) by Yáng​ Bān​hóu​ (楊班侯)

太極進退不已功

掤進捋退自然理，
陰陽水火相既濟。
先知四手得來真，
採捌肘靠方可許。
四隅從此演出來，
十三勢架永無已。
所以因之名長拳，
任君開展與收斂，
千萬不可離太極。

楊班侯

"That Peng advances and Lu retreats is the natural order,
As Yin and Yang, water and fire support each other.
First reach a genuine understanding of the four hands,
Then can the directions of Cai, Lie, Zhou and Kao be allowed.
Once the four cornes can be performed,
The thirteen postures go on without an end.
This is the reason for calling it Long Fist,
It allows one to master how to start and finish,
By all means one should not part from Tai Chi."

Based on the translation by Yang Jwing Ming (楊俊敏) presented in the book Tai Chi Secrets of the Yang Style (太極拳楊氏先哲秘要)

The Study of the Smashing Fist in Xingyi (形意崩拳學) from The Study of Xing Yi Quan (形意拳學)

形意崩拳學

崩拳者，屬木，是一氣之伸縮，兩手往來之理也。勢如連珠箭，在腹內則屬肝，在拳中即為崩，所謂崩拳如箭，屬木者是也。其拳順則肝氣舒，其拳謬則肝氣傷。肝氣傷則脾胃不和矣。其氣不舒，則橫拳亦必失和矣。此拳善能平氣舒肝，長精神，強筋骨，壯腦力，故學者，當細研究也。

孫祿堂

"The smashing fist is classified with wood and it contains the unified Qi of stretching and contracting, and both hands going back and forth in order. The motion is like a succession of arrows, in the body it belongs to the liver, in boxing it is smashing. It is said it is like an arrow, its category is wood. When the boxing is appropriate, the Qi in the liver will be comfortable. If the boxing is irregular, it will injure the liver’s Qi. If the liver’s Qi is injured, the spleen and the stomach will not work with each other. An irregular Qi in the liver will put the crossing fist in disharmony. This fist can make an even Qi to unfold in the liver, enhance the vitality, strengthen the tendons and the bones, and fortify the brain. For these reasons students should study it in detail."

From the book The Study of Xing Yiquan (形意拳學), by Sūn Lùtáng (孫祿堂), based on the translation by Albert Liu and Dan Miller.

Lǐ Bǐng​cí (李秉慈​) demonstrating Wú Style Tàijíquán (吳式太極拳)

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