Bai Fei is a special brushwork of calligraphy. According to legend, it was created by calligrapher Cai Yong, and was inspired by a craftsman who repaired the Hongmu Gate, and dipped a broom in lime water. When Emperor Lingdi of the Eastern Han Dynasty decorated Hongdu Gate, craftsmen wrote with a broom dipped in white powder. After Cai Yong saw it, he classified it as "Fei Bai Shu". Its stroke part is parallel to the dead silk, and the stroke at the turning point is prominent. In the Northern Song Dynasty, Huang Yue said, "Take the handwriting of its hair as white, and fly if you fly." Nowadays, the dry strokes of calligraphy and painting are generally called flying white, and the strokes are white, like a dry pen. Palace inscriptions were widely used during the Han and Wei Dynasties.