Gang Bing (simplified Chinese: ; traditional Chinese: ; pinyin: ; Wade–Giles: Kang Ping) was a Chinese general and eunuch who served under the Yongle Emperor of the Ming dynasty.
Gang Bing is most notable for his act of self-castration as a display of loyalty to his emperor. He served under the Yongle Emperor, the third emperor of the Ming dynasty who ruled over China from 1402 to 1424. Historical accounts describe Gang Bing as the emperor's favorite general. Because of this, the Yongle Emperor placed Gang Bing in charge of the palace in Beijing while he left for a hunting expedition.
At this point political intrigue within the walls of the Forbidden City forced Gang Bing to make a drastic choice. The Yongle Emperor possessed a large harem of concubines; sexual contact with a concubine by anyone other than the emperor was a severe offense. Fearing that rivals within the palace may accuse him of sexual improprieties with one of the 73 imperial concubines, Gang Bing decided to execute a plan of terrible self-infliction the night before the emperor left for his trip: he severed his own penis and testicles with a knife. The general then placed his severed organs into a bag under the saddle of the emperor’s horse.
As predicted, when the Yongle Emperor returned from his hunt, one of the emperor's ministers reported that Gang Bing had had inappropriate relations within the imperial harem. When accused of misconduct, Gang Bing instructed that the emperor's saddle be retrieved and requested that the emperor reach inside the bag under the saddle. Inside the bag, the emperor found Gang Bing's shriveled, blackened genitalia. Deeply impressed, the Yongle Emperor elevated Gang Bing to the rank of chief eunuch, a politically powerful position within the palace; gave him numerous gifts; and proclaimed him holy.