Su Shi is both a famous writer and a famous calligrapher. He once said in his poem: "Although I am not good at calligraphy, the little book is nothing like me;"

Su Shi believes that calligraphy is a profound knowledge. He has studied it carefully and practiced it hard, far better than others, but because of this, he feels that the depth of calligraphy is even more difficult to reach. All we can do is to know that she is profound and can't reach her limit. Personally, I don't think the author used modesty. What his whole poem wants to express is the profundity of calligraphy. If he is self-effacing, he has no such intention. I hope it will help you understand.