when Su Pingbei was caught in a difficult struggle, there was a sudden cry of killing on the north side.,saw Su Ping's north hand change into a fist, then waved heavily down, and all the Qin troops stood up at the same time.,the soldiers ambushed on the edge of the cliff riveted hard and pushed the prepared boulders around them off the cliff. When the stones were finished, they took out the tung oil they carried with them. Each soldier could not carry much tung oil, that is, the quantity of three kettles, but it could not hold a large number of people.。