东汉书法家蔡邕《九势》中说:“夫书肇于自然,自然既立,阴阳生矣,阴阳既生,形势出矣。藏头护尾,力在其中,下笔用力,肌肤之丽。故曰:势来不可止,势去不可遏,惟笔软则奇怪生焉。凡落笔结字,上皆覆下,下以承上,使其形势递相映带,无使势背。”“势”在《辞海》中的解释为:“冲发或冲击的力。形势、气势。”蔡邕说的“形势”可以理解为笔势。笔势是笔合乎情理的运行,由此而产生的刚柔、舒敛、虚 The Eastern Han calligrapher Cai Yong “nine potential” said: “The book originated in nature, both natural, Yin and Yang was born, both yin and yang, the situation out .Hidden head and tail, in which, under the force, the skin Lai. Therefore, the saying goes: the potential must not stop, the situation flies to fame, but the pen is strange and strange Yan Yan where all the words, all covered, under to undertake, so that the situation handed in with the reflection, no backs. ”“ Power ”in the“ Cihai ”in the explanation: “ The power of the shock or impact situation, momentum. ”Cai said “ situation ”can be interpreted as gestures. Gesture is a reasonable operation of the pen, the resulting rigid, Shu convergence, virtual