The Japanese threw themselves repeatedly against the defences of the two strong points, in the battles of Imphal and Kohima, but could not break through. At times the supply situation was perilous, but never totally critical. It came down to a battle of attrition, and the British forces could simply afford to fight that kind of battle for longer. In the end, the Japanese ran out of supplies, and suffered large casualties. They broke and fled back into Burma, pursued by elements of Fourteenth Army.