on opponents and allies of Datang Jianguo

When did Li Yuan start planning to attack the Sui Dynasty? It is difficultto find the truth in the historical materials of latergenerations. However, once Li Yuan decided to start his army, it wasobvious that he immediately made a well-planned and decisive action. Whatis Li Yuan's starting advantage? Thirteen years of Daye (617), Yang Diordered Li Yuan to stay in Taiyuan. He took his army to Lushu Valley (nowsouthwest of Jiexiu, Shanxi Province) to discuss the thief, "only five orsix thousand horses in all directions." , Betrayed the SuiDynasty. Li Yuan began to recruit soldiers in the name of LiuWuzhou. For about ten days, "thousands fewer people". InMay, Jia Zi (June 24), Li Yuan decided to form an army. In June (July 14),led by Li, captured Xihe County (now Shanxi Fenyang area) in southwestTaiyuan. It took nine days. On July 23, Tang Yuan reorganized itsarmaments. There were 30,000 military personnel at the time. In July,Renji (August 11), Li Yuan sent troops from Jinyang. The army descendedfrom the Fenhe River to Longmen and crossed the Yellow River to reach the easternsuburbs of Daxing City (that is, Tang Changan City). In October, the NewFourth Army (November 8), Li Yuan assembled more than 200,000 troops outsidethe East Chunming Gate of Daxing City. This time, the only majorobstruction encountered by Tang Jun this time was August 21 near Huo Yi (nowHuo County, Shanxi Province), surrounded by 20,000 veterans of the Sui Dynastymilitary commander Song Laosheng. After a hard counterattack, Tang Junfinally defeated the enemy. In addition, the entry plan can be said to haveprogressed very smoothly. Tang Gaozu himself is very proud. Threeyears later, when Wu De overtook Pei Ji, an old subordinate, for three years(620 years), he kept saying that when he shook his arms, people took himeverywhere. "Just a few months ago, he was promoted For the emperor." Of course, it is not an exaggeration to become emperor within a fewmonths, but Li Yuan did stabilize Chang'an City in just three months. Thereason why things went so smoothly is, of course, because of the loss of EmperorYang Di's heart. However, this alone is not enough.

Hedong Junxian County in the Sui Dynasty (Edited from Tan Qixiang, vol. 5,"Notes on the Startup and Living of Datang", China Map PublishingHouse, 1982)

In fact, on the way from Jinyang to Changan, Li Yuan's situation was not easyto deal with. The threat is greatest in both directions. One isNorthern Turkic and its affiliates-Mayi Liu Wuzhou. This is why Li Yuannanmust be modest and courteous. Large forces heading south must ensure stabilityin the rear. The second is Xue Ju, who was founded by Jincheng (nowLanzhou, Gansu) in the west. At that time, Xue Ju controlled Longxi with aforce of 130,000. When Li Yuan's road to Huo Yi was blocked, Xue Juoccupied Zhouqin in the east (now Tianshui, Gansu). He claimed to support300,000 troops and surrounded Fufeng (now Shaanxi Fengxiang) with Changan asits target. not only these. Xue Ju was based on the national ranch ofthe Sui Dynasty. In addition, he also received help from the HexiTatars. He is quite powerful. Moreover, he is closer toChangan. Therefore, this armed force is actually the biggest variable for

Tang Jun's success or failure. Tang Gaozu certainly understands this,and he has been alert in advance. This can be seen in the strategicarrangement of Tang Li's reorganization of arms before the Yang Jinuprising. Li Yuan organized his 30,000 officers to form the left, middle,and right. His third sons, Li and Li Yuanji, respectively served asgovernors. Taking this opportunity, he divided the third son into threegroups. The Li brothers were called Dalang, Erlang and Silang. Later, theyhad a loud and formal name, namely Li Jian was Longxi Gong, Li Shimin wasDunhuang Gong, and Li Yuanji was an ancient Tibetan man. This titlecontinued until November 26 (December 26) of the year, a week after Li Yuangreeted the emperor's grandson and acting king in Tianxing Hall and changedYuan to Yining. Li changed his name to Tang Shizi, Qin Gong, and LiYuanji. In other words, the third son of the Li family divided Longxi formore than four months. This is a strategic plan to enter the customs,which is obviously aimed at the separatist forces in Hexi, such as dramasnow. However, why can Li Yuan make such a package?

An article by Mr. Shi Jianqing's "Atlas of Chinese History" (includedin "The Founding of the Tang Dynasty and the Huns' Fee Head", firstpublished in Japanese in 1998) specifically studied this issue. Mr. ShiJian believes that Li Yuan's third son was assigned to Longxi not because of LiYuan's family background, but because of Li Yuan's wife Dou's family. Mr.Shi Jian deconstructed the pedigree of the Dou family by peeling the cocoons,and found that the Dou family came from the flying leaf head (also calledflying leaf head or broken leaf head) of the Xiongnu. This is a nomadictribe active in the Ordos region, with strong independence. Its power evendeveloped into the Hexi Corridor. After the split between the Eastern andWestern Wei dynasties, Ye Fei's head became a power contested by Eastern andWestern rulers. Therefore, he had the opportunity to step on the stage ofhistory and enter the handed down documents. Therefore, Mr. Shi Jianbelieves that Li Yuan