How did the fake painter Qi Baishi deceive people?

Qi Baishi is a fake painter. He knows nothing about art. He is just a carpenter. Because of his good relationship with Xu Beihong, he was promoted to be a painter. In fact, Qi Baishi was not famous at all in the Republic of China. In the 1980s, some people bought a batch of Qi Baishi's paintings at a price of several yuan each, and now they take them out for speculation.