Borrow military forces from fortune tellers

What is Sun Ce's use of Yuan Bing's seal?

At first, Sun Jian got it, and it was under the command of Yuan Shu. He didn't want to pay it himself, and he wanted to be emperor himself, but this imperial seal was a hot potato, which caused him a disaster and was killed by Liu Biao's subordinate Huang Zu. Sun Ce, his son, was clever, so he told Yuan Shu to change soldiers and go to Jiangdong to fight Yuan Shu. Yuan Shu is really stupid and wants to be an emperor. He thought he could give orders with this thing, so he gave it to him Then Sun Ce wanted Sun Jian's old generals: Cheng Pu, Han Dang, Zu Mao and Huang Gai, all of whom had followed Sun Jian for many years. So Sun Ce took these people to Jiangdong to farmland.