After joining his ranks, Jiao Yu became one of Zhu Yuanzhang's trusted confidants in the Red Turban Rebellion against the Yuan dynasty. Zhu was impressed with Jiao's knowledge of firearms which he had earlier acquired from Daoren, yet Zhu wanted to test their abilities. Zhu ordered his officer Xu Da to provide a demonstration of their destructive capabilities, and after the display Zhu Yuanzhang was most impressed with their power.
After joining Zhu Yuanzhang's army, Jiao Yu became one of his most trusted allies in the Red Turban Rebellion against the Yuan dynasty. Zhu was impressed by Jiao's knowledge of firearms, which he had acquired from Daoren, and wanted to assess their capabilities. He instructed Xu Da to showcase their destructive potential, and after the display, Zhu Yuanzhang was deeply impressed with their might.