Dai Song was a famous painter in Tang dynasty and his paintings of ox were always cherished by Brahmins.

In Song dynasty, a person who lived in Sichuan province with a surname of Du collected a painting of ox by Dai Song, and he cherished it very much and often took it out to appreciate it. And he even often dries it in sunny days.

Once a shepherd boy saw this painting and couldn't help laughing, thinking that the painting was to depict a fighting ox, but in this painting the tail of the ox was raised high, which was quite different from what he had observed before. In fighting, the tail of the ox should he between the legs. So this painting had this wrong. The Sichuan person with the surname of Du agreed with the shepherd boy and didn't cherish it that much any longer.

唐代著名畫家戴蒿所畫的牛歷來為文人雅士鐘愛。

宋朝一個姓杜的四川人藏有一幅戴蒿的斗牛畫，十分珍惜，經常帶在身邊把玩，天氣好時還不時拿出來晾曬.

一個牧童看見這幅圖畫，不覺笑起來，認為畫是“斗牛圖”，牛的尾巴卻翹起了，和他所見斗牛時牛尾巴夾在牛腿間完全不一樣，這幅畫錯了的斗牛圖不值得這么重視。姓杜的四川人完全贊同牧童的觀點。將這幅畫降低了收藏規格。