How much is the quick calligraphy and painting in Yindu worth?

Teacher Yin's 40-year skill accumulation has made him a self-contained book style today. Now the price of Runge Certificate is 8,000 yuan/square foot, and it is estimated that the actual transaction price is around 2,000 yuan-3,000 yuan/square foot. Because he is low-key and doesn't like publicity, he hasn't been recognized by the fans. Friends who have a collection vision can pay attention to it, and the appreciation potential is huge, especially Teacher Yin's lower case.