Japanese conquest of Burma main attack westward from Rahaeng in Thailand across the Kawkareik Pass. The 16th Indian Infantry Brigade of the 17th Indian Division guarding this approach retreated hastily westward. The Japanese division advanced to Moulmein at the mouth of the Salween River which was garrisoned by the 2nd Burma Infantry Brigade. The position was almost impossible to defend, and had the River Salween, almost wide, behind it. The 2nd Burma Brigade was squeezed into a progressively tighter perimeter, and eventually retreated over the river by ferry on 31 January after abandoning a large amount of supplies and equipment. Part of the force
Malaysia–Thailand border the Straits of Malacca and in the Gulf of Thailand/South China Sea. At the western terminus of the land boundary, the 1909 Anglo-Siamese treaty determines the start of the maritime boundary as: The territorial sea boundary agreement between the two countries signed on 24 October 1979 determined the mid-channel point between Langkawi and Tarutao to be at which was made the eastern starting point of the territorial sea boundary. Both countries also have a continental shelf boundary agreement for this segment of their maritime boundary. The agreement, signed 21 December 1978, included Indonesia as a signatory to enable the establishment