First of the Five Classic, this version of The Tai Chi Chuan Lun (Discourse) is a translation by my teacher, Dan Docherty. He has written more than one book on this subject, with commentary, covering this Classic.
Translated by Dan Docherty
Once you move, the whole body must be light and agile,
In particular, it must be linked together.
The Chi (Vital Energy) should be aroused and agitated,
While the Shen (Spirit) must be internally hoarded.
No place should be deficient or defective,
No place should have hollows or bumps.
No place should be cut off or extended.
The root is in the feet;
Discharging is done by the legs,
The controlling power is in the waist,
And the appearance is in the hand and fingers.
From the feet to the legs to the waist,
All must be completely uniform and simultaneous,
Whether stepping forward or moving back.
This will result in good timing and correct movements.
If in certain places good timing and correct movement are not achieved,
Body movements become arbitrary and disordered.
This sickness must be sought in the waist and leg.
Above and below, forward and back, left and right are all like this.
In general this is controlled by the Yi (Intent) and not externally.
If there is up, immediately there is down;
If there is forward, immediately there is back;
If there is left, immediately there is right.
If the Yi is to go up,
The Yi to go down is there immediately.
Or, if you raise something up,
Then there is the Yi to smash it down with increased force.
In this way its roots will be severed
And destruction will be swift and beyond doubt.
Void and Substantial must be clearly distinguished.
Each place of course has its individual balance of void and substantial,
Every place consists of this, one Void and Substantial.
Every part of the body in turn is strung together,
Without causing the least break.
This Tai Chi,
It’s like the great river, the Chang Jiang,
Surging and flowing without interruption.
Of the Thirteen Tactics,
Peng, Lu, Ji, An, Cai, Lie, Zhou and Kao;
They are the Eight Trigrams.
Step Forward, Move Back, Face Left, Look Right and Centrally Fixed;
These are the Five Elements.
Peng, Lu, Ji and An,
Are the trigrams Chien, Kun, Kan, Li, the four cardinal points.
Cai, Lie, Zhou and Kao
Are the trigrams Sun, Chen, Tui, Ken the four corners.
Step Forward, Move Back, Face Left, Look Right and Centrally Fixed;
Are Metal, Wood, Water, Fire and Earth.