Tang Dynasty master Zen monk Congshen presided over Guanyin Temple in Zhaojun for many years. It is said he was extremely strict with his disciples, requiring them to sit in meditation, concentrate their minds, and ignore all external distractions to achieve a state of stillness and detachment. One evening during meditation, Master Congshen deliberately said:
"Tonight's dialogue — let those who have heard the Dharma and attained enlightenment come forward."
At this moment, the disciples should all be sitting cross-legged, eyes closed and minds focused, motionless and unwavering. Yet one young monk, unable to contain himself, presumed to act as the questioner and stepped forward to bow. Master Congshen glanced at him and said slowly, "I had cast a brick to attract jade, but instead I've drawn a clay lump even worse than the brick!"
Here is another story, "Throwing a Brick to Attract Jade." According to records in *Anecdotes of Poetry Through the Ages* and other texts, the Tang Dynasty poet Zhao Gu earned the admiration of the great poet Du Mu with his exquisite line, "A single flute's note, a man leans on the railing," earning him the nickname "Zhao of the Railing." At that time, another poet named Chang Jian, who had long admired Zhao Gu's talent, heard that Zhao Gu was visiting the Wu region. Certain that Zhao Gu would visit Lingyan Temple, Chang Jian hurried there first and inscribed two lines of poetry on the temple's front wall, hoping Zhao Gu would complete the poem. As expected, when Zhao Gu saw the two lines on the wall, inspiration struck, and he added two more lines, finishing the quatrain. Since Chang Jian's verse was inferior to Zhao Gu's, his lesser lines had "attracted" Zhao Gu's superior ones—a practice later called "throwing a brick to attract jade." In truth, Chang Jian and Zhao Gu were not contemporaries, living over a century apart, so the story is likely fictional. However, because the tale is so famous, it is still accepted as one of the origins of this idiom.
Later, the idiom "Brick to Attract Jade" is often used as a humble expression to offer one's own shallow or immature opinions or writings in order to elicit others' valuable insights or masterpieces.
Source: *Jingde Record of the Transmission of the Lamp* by Shi Daoyuan (Song Dynasty)
Meaning of the Idiom: Later, the Chinese idiom "抛砖引玉" came to describe how one's own shallow or immature opinions or writings are offered to elicit others' valuable insights or masterpieces.