Zhuangzi, a health care master. The expert who knows cattle is an idiom, which originated from Zhuangzi's "Zhuangzi Health Master". Zhuangzi, the Master of Health Preservation, is an article written by Zhuang Zhou, a philosopher and writer in the Warring States Period, which is contained in the Inner Chapter of Zhuangzi. This is an article about keeping in good health. It embodies the author's philosophy and life purport. Excerpt from the original text: "I am good at understanding cows for the text. Touch of hands, tilt of shoulders, stepping of feet, stepping of knees, sound of knives, tenor. Wen Huijun praised his skill. My expert explains Dao Yun like this: I have killed thousands of cows in my life, but now it is God's will to fool people, and I have never seen all the cows. If I cut the cow, I will be very comfortable. Therefore, although it has been used for 19 years, its sharpness is still as good as new. "

In this idiom, experts know how to understand cattle, describe people with a knife, describe complex society with the organization of cattle, and describe people's social life with a knife. Zhuangzi believes that people should find ways to adapt to society and avoid all kinds of contradictions in real life, so as not to be hurt. This idiom reveals a way to keep fit and live in the world. This word can also be used to mean that after repeated practice, I have mastered the objective laws of things, and I am comfortable with things and use them freely.