There is no reliable information about the origin of this finger-hooking oath, so that some people think that finger-hooking was introduced from the west and originated from a love legend triggered by a man and a woman in the west. This statement seems to be conclusive, but due to the lack of factual basis, it is difficult to fully convince people.
It is considered that the origin of hook finger may be related to the function of finger. Refers to the meaning of "purport" and represents one's inner thoughts and intentions. Hooking your fingers means communicating your inner thoughts. In addition, there was a form of swearing by heaven in ancient times, so "finger" played an important role in swearing. In the oath, the finger should be signed, and it should be signed solemnly. Sometimes, for the sake of alliance, it is necessary to cut the finger and bleed. In view of this, people simply use their fingers to express their vows, and at the same time use their fingers to communicate and express their wishes. Sometimes, their thumbs are used as seals and their signatures are used as evidence.
However, there is also an oath of high-five. For example, Peking Opera, Henan Opera, Shaanxi Opera and Sichuan Opera all have a play "Wang Baochuan", in which there is a "three-high-five" aria, which tells that the protagonist and his family must clap their hands and swear that they are willing to leave Xiangfu and marry the beggar Xue Pinggui. The high-five here is a swearing action, which means that you will keep your word and never break your word. It is similar to the action of hooking your fingers and has a similar effect.
At first, high-five was not an oath, but a form of dance. In ichalky, dancers get carried away and can't help dancing. They kept clapping back and forth with the rhythm of the music to enliven the atmosphere and enhance the effect. Qizil Grottoes in Xinjiang have murals of ancient people clapping their hands when dancing. It is estimated that the applause that rose later evolved from the aristocratic high-five watching the dance to the high-five dancing.
When the ancients were in high spirits, they often kept clapping to vent some emotions. Because of the special position of palm in life, high-five was later used to exchange palm prints and solemnly represent vows. During the Ming and Qing dynasties, high-five became a common action when pledging. For example, Zhan Zhao and Bai Yutang in "Three Heroes and Five Righteousness" high-fived each other and agreed to compete. The ladies-in-waiting in "Hu Siniang" also high-fived for oath.