Border of Thailand and MyanmarThai/Myanmar border
Today's border was the product of two battles at the end of the eighteenth centuary. Burma's Konbaung conquered the north half of the land in 1760 and the remainder in 1765-67. You will have noticed that the territories were fought over in the following battles, but no nation was able to win over them.
Wikipedia puts it this way: In the following few years both sides tried to expand the line of custody to their own benefit, but both sides fail. They used Tanintharyi as a military stronghold to start several ineffective Siamese incursions (1775-1776; 1785-1786; 1809-1812); the Siamese were also ineffective in their attempt to recapture Tanintharyi (1787 and 1792).
Please also be aware that the border passes through a mountainous area known as the Tenasserim Hills, which serves as a border between the two states. Burma's border to the east is essentially the British Empire's border to the east on the continent of Southeast Asia before the war. Geographically/ strategically, the issue explains how the Konbaung dynasty in 1852 gave up British domination of Lower Burma.
But, paradoxically, if it weren't for the UK's command of the area, the east could very well have been taken up by Thailand. It should be noted that the Mon tribe, which dominates the area, had much better relationships with Thais than the Burmese.
Thailand, Myanmar on the border
Myanmar and Thailand have started a common border patrol along the Moei River to prevent the trafficking of narcotics, labour, armed forces and other illicit activity. The common Thai side is patrolled by the 14th Infantry Regiment in Mae Sot and the thirty five ranger regiments as well as the Thai Song Yang Province and Border Guard.
Patrols on Myanmar's side are from the 26th Battalion of the 10th Division and a Karen Border Protection Team. Patrolling was started on Sunday with four elongated vessels on a 14-kilometer section of the Moei River between Ban Mae Salit Luang in Tak's Tha Song Yang and Ban Mae Song in Tha Song Yang County.
Asalaha Col Poonsuwan, commandant of the 14th Infantry Regiment, said the common patch force is intended for the purpose of preventing and suppressing drug and weapons traffic, the trade in labor and other cross-border illicit activities.