Ascertain the doubtful; find out about the enemy before taking action. Return and bring the enemy’s secrets to light.

This expression comes from a story in a Tang Dynasty sketchbook. The magistrate of Dangtu District, as the story goes, was a greedy man who accpeted as many bribes as he was offered. Once, some locals handed in pertition, accusing the assitant magistrate of taking bribes. Astounded upon reading it, the magistrate scribbled the following: “You only beat the grass, buy the smake is frightened.”

Sometimes one might not want to beat the grass for fear of startling the snake into preparedness or excape. Likewise, a military commander is often cautioned to refrain from minor, impulsive engagements with the enemy for fear of exposing his intensions and the deployment of his troops. This is especially true when he is preparing a surprise attack. Under other circumstances, however, it is advisable to take an open, albeit and weakness before launching an all-out offensive.