In the 11th century, during the period when Song and Liao dynasties coexisted, the various Jurchen tribes in Northeast China gradually grew stronger and finally unified. After eleven years of warfare (1114-1125), with distant support from the Song army, the Jurchen ultimately took the initiative and brought down the Liao Dynasty. They often won despite being outnumbered, thus earning the reputation of the “invincible Jurchen.” Having studied ancient military history for years, the author narrates the decisions made by both sides and the specifics of the battles in simple and accessible language. The book not only describes the intense battles between soldiers, the comparison of offensive and defensive strategies, military tactics, and weaponry, but also summarizes the patterns of warfare, striving to uncover the secrets of victory and defeat.