In the late 18th century, Vietnam was experiencing significant political turmoil, which provided an opportunity for external forces, particularly from Siam, to exploit the situation. The Siamese, seeking to intervene and expand their influence in the region, moved towards Vietnam with a sizeable military contingent. Unbeknownst to them, the Tây Sơn forces, a rising revolutionary group led by the brothers Nguyễn Nhạc, Nguyễn Huệ, and Nguyễn Lữ, were well-prepared and fully aware of the Siamese intentions. They took strategic measures to leverage the element of surprise against the invading force. On the banks of the Mekong River, a fierce battle ensued as the Tây Sơn launched a well-coordinated ambush on January 20, 1785. The Siamese forces found themselves caught off guard and were quickly overwhelmed. This engagement was characterized by intense close-quarters combat, showcasing the tactical superiority and coordination of the Tây Sơn troops. The Siamese suffered devastating losses, with the majority of their troops annihilated in the encounter. This battle not only thwarted the Siamese invasion but also solidified the Tây Sơn's reputation as formidable defenders of Vietnam.