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
Geology of Myanmar India and the Eurasia Plate led to the formation of the Himalayan Orogeny. On the eastern margin of the India plate, high oblique subduction occurs between the boundary of India and the Burma-micro plate. Between late Eocene to Miocene, the Burma and Shan-Thai block rotated 30° to 40° clockwise, to accommodate the major collision along the plate boundary. This resulted in the trend of arc shifting from east-west to the north-south direction. The subduction boundary forms an accretionary prism and eventually with thrusting and folding forms the Indo-Burma Range. In late Miocene to Pliocene, the slab detachment of Burma-microplate beneath