What is the meaning of the Tibetan front against the wind mentioned in the brush copybook?

A cluster of long and pointed parts in the center of the brush head is called "Feng", and short hairs around it are called "Fu Milli". The writing brush is made in this way to hold ink in the middle of the pen tip. When the pen tip stippling moves, the ink will flow down along the pen tip where it moves, instead of tilting up and down and left and right, but seep evenly in all directions.

"Hidden front" means: "If you want to look left and right, you should go up first and then down", that is, at the beginning of a stroke, the pen tip is hidden in the stroke by writing in the opposite direction. The ancients said: "hide the front to cover its qi, and expose the front to longitudinal its waves"; "If there is a front, it will be light, and if there is no front, it will be spiritual." Tibetan positive strokes are round and thick; Lu Feng's brushwork is sharp and full of spirit.

"Reverse" means that the pen holder leans in the opposite direction to the pen. "Back-front" means that the pen tip is retrograde (that is, in the opposite direction to the habitual pen movement), and the effect is dry and childish.