In period dramas or historical scrolls, it is common to see emperors holding court or going on tours with attendants holding two large fans. Many people think these fans were used to cool the emperor, but in fact, fans in ancient times were originally 'ceremonial vessels' symbolizing supreme power. It was only during the Han dynasty that they gradually acquired the function of cooling. Throughout history, these two large fans not only represented the sanctity of imperial power but even evolved into hidden defensive weapons kept close to the emperor.

What was the purpose of the large fans behind the emperor? The Tang dynasty created the 'Suo Shan system' (fan-covering system), using fans to screen the emperor's face and enhance imperial dignity. In Ban Gu's 'Bamboo Fan Rhapsody', it is written: 'Shaved into a fan, it becomes a beautiful vessel, entrusted to the emperor for timely use,' indicating the inseparable relationship between fans and royal power. By the Tang dynasty, strict regulations governed the shape, quantity, and style of ceremonial fans. During Emperor Xuanzong's reign, minister Xiao Song established the famous 'Suo Shan system'. When the emperor held court, six large fans would be closed together in front of the throne to block ministers from directly gazing at the emperor's face. Only after the emperor was seated would the fans be opened, allowing officials to pay homage, with three fans standing on each side. At the end of court, the fans would again close to screen the throne until the emperor left.

During the height of the Tang dynasty, imperial tours used a combination of umbrellas and pheasant-tail fans. Pheasant-tail fans were exclusive to the emperor and princes, while ordinary officials could only use round fans. The selection of fan bearers was extremely strict, usually choosing tall, handsome young men from the families of court officials.

After Emperor Yongle of the Ming dynasty seized the throne through the 'Jingnan Rebellion', he lived in constant fear of assassination because his predecessor's fate was unknown. For instance, court official Jing Qing once attempted to assassinate Emperor Yongle with a blade. Ming dynasty statesman Lu Rong recorded in his 'Garden of Beans Miscellany' that when Emperor Yongle held court at the Fengtian Gate, eunuchs behind the throne always held a small fan wrapped in yellow silk. This item, called 'Zhuoying Bixie', was said to be a tribute from foreign lands. Modern Palace Museum scholar Shan Shiyuan, in his 'Stories of the Forbidden City', researched that 'Zhuoying Bixie' was actually a three-bladed sword-like weapon. To avoid accidentally injuring the emperor and to disguise it, the outer layer was wrapped with iron wire and yellow silk into the shape of a fan. In an emergency, the eunuch holding the fan would shake his arm, causing the wire to fall off and reveal the blade for defense.

As the political situation stabilized and threats to imperial power diminished, the practical need for such self-defense weapons declined. By the late Qing dynasty under Emperor Xuantong, these devices had transformed from hidden defensive weapons into purely functional fans, mainly used to improve indoor air circulation and environmental conditions, earning the name 'plague-avoiding fans'.

These two large fans standing behind the emperor—from symbols of power and face-screening in the Han and Tang dynasties, to disguised weapons in the Ming dynasty, and finally returning to ventilation function—witness centuries of changes in court rituals and political situations.