According to Cui Bao's "Gǔjīn Zhù" (Ancient and Modern Records): When King Wu of Zhou was campaigning against King Zhou of Shang, a strong wind broke the canopy of his chariot. Jiang Taigong then created a curved canopy (qūgài) based on the shape of the broken canopy. During the Warring States period, it was often used as a reward for generals. Since the Han Dynasty, the emperor's chariot has used a four-sided canopy called the chēgài (chariot canopy) or línái gài (línái canopy), which is the present-day folding umbrella. The commentary states: "Línái refers to a chariot canopy." According to "Jíyùn" (Collection of Rhymes): The character 䡟 is pronounced "pǐ jì" and sounds the same as "pì." 䡟línái is the name of a type of chariot. The character 䡶 is not recorded in character dictionaries, and it is suspected to be the same as 䡟. This is preserved for examination.