The Burmese–Siamese War (1785–1786), known as the Nine Armies' Wars in Siamese history because the Burmese came in nine armies, was fought between the Konbaung dynasty of Burma and the Chakri dynasty of resurgent Siam (Thailand).
King Bodawpaya of Burma pursued an ambitious campaign to expand his dominions into the lands of the former Ayutthaya Kingdom. His armies attacked Lanna in northern Siam, where the governor of Lampang managed to partly halt the Burmese, waiting for the troops from Bangkok. As Phitsanulok was captured, Rama I, himself, led an army to the north.
In the south, Bodawpaya lie waiting at Chedi Sam Ong. The Front Palace (Maha Sura Singhanat) led his troops to the south the counter-attack the Burmese that came from Ranong through Nakhon Si Thammarat — the engagements occurred at Kanchanaburi. The Burmese also attacked Thalang (Phuket), where to governor had just died. Chan, wife of the governor, and her sister Mook gathered people to defend Thalang against the Burmese. Today, Chan and Mook are revered as the two heroines, Thao Thepkrasattri and Thao Seesunthon.
The Burmese proceeded to capture Songkhla. Upon hearing the news, the governors of Phatthalung Province fled. However, a monk named Phra Maha headed a force of villagers against the Burmese. Phra Maha was later raised to Phraya Thukkharat by Rama I.
As his armies were destroyed, Bodawpaya retreated, only to renew attacks the next year (1786). Bodawpaya, this time, didn’t divide his troops but instead formed into single army. Bodawpaya passed through the Chedi Sam Ong and settled in Ta Din Dang. The Front Palace marched the Siamese forces to face Bodawpaya. The fighting was very short and Bodawpaya was quickly defeated. This short war was called “Ta Din Dang campaign”.
The campaign is commemorated by a park established by the Royal Thai Army 40 kilometres (25 mi) from the town of Kanchanaburi.