This paper analyzes the Goguryo-Sui War in 613, that is, the preparations for the Second Goguryo Invasion War of Yangdi, the second emperor of Sui dynasty and the tyrant emperor destroying the country by losing the War. The Goguryo-Sui War in 613 began immediately after the Sui army withdrew following their defeat at the Battle of Salsu in 612. In the same year, grain from warehouses such as Liyang, Luoyang, Luokou, and Taiyuan was transferred to Wanghaidun. The loser emperor summoned the commoners and organized them into xiaoguo, in 613. During the Goguryo-Sui War in 613, an additional 2,604,900 people had to be mobilized, including soldiers and transporters of military supplies, out of a total of approximately 3,928,193 people. This corresponds to 67.2% of adult males called keding(課丁) who can afford to pay taxes, military service, and corvée, and it was bound to be a huge burden on the people.
Although the Sui government had to replenish 241,840 horses and weapons, it suffered a major blow, before the second invasion of Goguryeo, when Bai Yusha, one of thieves group, plundered the pasture horses in the Longyou region in January 613. In this way, during the Goguryeo-Sui War in 613, the Sui army fought Goguryeo in a situation where they were unable to properly receive military supplies due to the loss of military horses, the prevalence of bandits, and the delay in the transport of military supplies by Yang Xuangan, the person in charge of military supplies. However, when Yang Xuangan rebelled, he could not hold out any longer and had no choice but to withdraw.