Throw out a brick to attract a jade

It's used to describe: Educe better advice of others by own plain one.

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It was said that a poet named Chang Jian of the Tang Dynasty one day heard that Zhao Gu would visited Ling Yan Temple of Su Zhou. In order to invite Zhao Gu to poetize, he wrote down two sentences on the wall in advance. Sure enough this unfinished poem attracted Zhao Gu's attention, and he wrote down another two more wonderful sentences to finish this poem. Later on people described Chang Jian's action as " Throw out a brick to attract a jade ".

Now people try to use this statement which indicates that one first establishes a superficial opinion or analogy in order to lead others setup higher purposes or features, the statement shows kind of modest spirit. When it has application in military affairs, people use some similar things to confuse and lure the enemy, then they can find a chance to defeat them.