 The division's HQ and two brigades went to Imphal, the other brigade (the 161st Indian Infantry Brigade) went to Dimapur from where it sent a detachment to Kohima.While the Allied forces in Imphal were cut off and besieged, the Japanese 31st Division, consisting of 20,000 men under Lieutenant-General Kotoku Sato, advanced up the Imphal–Dimapur road.Instead of isolating the small garrison at Kohima and pressing on with his main force to Dimapur, Sato chose to concentrate on capturing the hill station.