The Iril River Valley runs almost parallel to the Imphal-Kohima Road. The two are separated by a collection of hills. According to Lyman, these hills, bound by Molvom in the north and Mapao in the south, became during the Battle of Imphal ‘a Japanese defensive arena par excellence’. The 5th Indian Division was active west of the Iril River, while to its east were the British formations covering the Ukhrul Road. As with the Imphal-Kohima Road, the British faced the Japanese 15th Division in this sector.
After the initial thrust by the Japanese, aimed at capturing Imphal, the bulk of the subsequent fighting consisted of British efforts to dislodge the former from the area. The hills known as Nunshigum and what the British called Runaway Hill along the Iril River, as well those around Molvom and Mapao, were some of the major battlefields here.
The Battle of Nungshigum, from April 7-15, 1944, was the iconic battle of this sector. It involved a struggle for the recapture of Nungshigum massif from the Japanese, which was the closest they ever came to Imphal from the north. The British used a combination of armour, artillery and infantry in the battle, together with support from the air. General Slim gives a riveting description in Defeat into Victory: ‘On the 13th [of April, 1944], while Hurribombers, their guns blazing, dived almost into the tree tops, and tanks, winched up incredible slopes, fired point-blank into bunker loopholes, our infantry stormed both peaks [of Nungshigum] – and held them. The Japanese grimly defended their positions until the last men still fighting were bombed or bayoneted in their last foxholes’. Casualties were heavy in the battle, with Lyman estimating that some 250 men were killed on the Japanese side alone.