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
River systems of Thailand Mekong River Commission. The extreme seasonal variations in flow and the presence of rapids and waterfalls have made navigation extremely difficult. Approximately half the river's length is in China, where it is known as the "Lancang Jiang" (澜沧江 Láncāng Jiāng) or "Meigong" in Chinese (). The river forms the border between Myanmar and Laos for , at the end of which it meets the tributary Ruak River at the Golden Triangle. This point also marks the division between the "Upper" and "Lower Mekong". The river then divides Laos and Thailand, before a stretch passing through Laos alone. It is known