However, people's understanding of the surname of the historical figure Gai is very vague. According to folklore, his surname is Gai (pronounced "Ge"), which is derived from the family of member Gai. Up to now, people around Dashiqiao and Gaizhou in Yingkou still talk about the story of Gai's sister Gai guarding Qingshiguan, and there is a so-called "Gai Tomb" near Qingshiling.
However, by studying China's official historical documents, it clearly records Gai's surname. "The Biography of the New Tang Dynasty in Korea" records: "You Gai, or Gai Jin, surnamed Quan." Zi Tong Zhi Jian (volume 198) records: "Wu Wang was killed by adult Chun in eastern Korea." The same book volume 20 1 also contains: "In the first year of Ganfeng, Quan Gai died, and the eldest son authorized the boy to replace Molly." It can be seen that "Gai Suwen" is just a name, not a name. His full name should be Quan Gai, and his three sons are all surnamed Quan: the eldest son and the whole boy. There is a legend in the Book of the New Tang Dynasty: "The whole boy is virtuous, a beggar knows state affairs ..." The second son Quan Nanjian is also recorded in the history books. Zi Zhi Tong Jian (Volume 20 1): "Quannan Jian sent troops to attack its camp, and General Xue Guiren of Zuo Wuwei broke it."
Most of the epitaphs of Quantongzi brothers and their descendants were unearthed near Mangshan, a suburb of Luoyang. The epitaph of Quantongzi's epitaph is "Epitaph of Tang Dynasty entering the whole county specially"; The inscription on the property epitaph of Quannan is called "Epitaph of Dazhouquan Fujun"; The epitaph of Quan Xiancheng, the son of the whole boy, was not covered. The first inscription was "General Quan Jun's epitaph, which was given by General Zuo Wei in the Zhou Dynasty"; The epitaph of the son of Quan Xiancheng is not covered, and the inscription is "Epitaph of Quan Jun, the founding son of Zichuan County in Tang Dynasty".
Judging from the above documents and unearthed objects, there seems to be no doubt that Gai's surname is "Quan". However, the historical work A General History of Korea published by North Korea was written as "Yuan changed to Su Wen", and the History of Koguryo Empire written by South Korean scholar Xu Bingguo and the Outline of China People's History written by Bai Yang, a scholar from Taiwan Province Province of China were also written as "Yuan changed to Su Wen". So which words are "spring" and "deep"?
To understand this problem, it is necessary to involve the taboo system in ancient China. In ancient China, the names of all emperors were avoided, and the taboo place names, official names, personal names and even animal names were changed to another similar word. In the Tang Dynasty, in order to avoid Li Yuan's taboo, most of the words "Yuan" were rewritten as "Quan" (a few were changed to "Shen"). Mr. Chen Yuan made a detailed textual research in Examples of Historical Taboos. Here are some examples of the change from "yuan" to "whole" in historical taboos to prove it:
1, "Biography of Old Tang Nv": "Wei, the wife of Song Dynasty, is also behind the work of Lang Yanquan." Yan Quan should be Yan Yuan, avoiding the Tang Dynasty and seeking change.
2. Geography of the Book of Jin: Qingquan County, Yangping County. Qingquan, which is clear and deep, avoids the Tang Dynasty and pursues it.
3. Biography of Northern History and Zhang Zhan: "Dunhuang Shenquan people are also." Deep springs are an abyss, and it is taboo to avoid the Tang Dynasty and seek reform. Before the Tang Dynasty, it was not famous for deep springs.
4. Geography of the Old Tang Dynasty: Linqing, Hanqingquan County. Qingquan, whose real name is Qingyuan in Chinese, was shunned by the Tang people.
5. The Biography of Xian Di in the Later Han Dynasty: "In the second year of Xingping, Lu Xun and Deng Quan were killed." Taking the Five Elements as the book Deng Yuan, this is Zhang Huaigai's Spring.
The change of Yuan's surname to "Yuan" undoubtedly violated the national taboo of the Tang Dynasty, so it was rewritten as "Quan" in the literature of the Tang Dynasty. As for the Yuan boy brothers, as North Korean generals, they had to "do as the Romans do". Their ancestral surnames were too big and were forbidden by the court, so they had to change their surnames to "Yuan" and "Quan Jun" appeared on the epitaph.
Through the above textual research, we can see that "Yuan" is Gai's real surname, and "Quan" is an alternative word rewritten in the Tang Dynasty to avoid the taboo of Li Yuan's name. As for the word "brother" among the people, it is even more nonsense.