Within six months of its raising, the regiment was ordered to move to Digboi to defend the oil fields. In early 1942, it moved to Ledo and was involved in reconnoitering the alignment for the famous Stilwell Road. In 1944, when the invasion of India by Japan was imminent, the regiment was moved to Jessami and Kharasom to delay the advance of the Japanese 31st Division. The young regiment soon proved its capabilities within three years of its raising, at the consecutive battles of Jessami, the epic defence of Kohima and the capture of Aradura, all of which were awarded as battle honours (now known as pre-independence battle honours) to the regiment.