The mountain ranges to the west of the Chindwin are formidable, yet not totally impregnable to armies. The Kabaw valley saw many an invasion by the kingdom of
Manipur to the west, most notably during the reign of King
Garibaniwaj (1709–1748) when his army crossed over the Chindwin and the
Mu, took Myedu, and reached as far as Sagaing opposite the capital
Ava. The tables were turned in 1758 after King
Alaungpaya ascended the Burmese throne. The Burmese army invaded and occupied
Manipur and
Assam marching across the western mountain ranges, and even encroached upon British India. During
World War II, when the
Japanese had cut off sea access, the British army and other
Allied forces under General
Joseph Stilwell retreated on foot to India across the same mountains, with disastrous results, mainly due to disease and hunger. The
Ledo Road was built across the Hukawng valley to supply China. The Chindwin was a major barrier both for the Japanese trying to invade India and for the Allied forces attempting to reoccupy Burma. == Ethnography and culture ==