Hanoi had underestimated the strategic mobility of the allied forces, which allowed them to redeploy at will to threatened areas; their battle plan was too complex and difficult to coordinate, which was amply demonstrated by the 30 January attacks; their violation of the principle of mass, attacking everywhere instead of concentrating their forces on a few specific targets, allowed their forces to be defeated piecemeal; the launching of massed attacks headlong into the teeth of vastly superior firepower; and last, but not least, the incorrect assumptions upon which the entire campaign was based. According to General Tran Van Tra: "We did not correctly evaluate the specific balance of forces between ourselves and the enemy, did not fully realize that the enemy still had considerable capabilities, and that our capabilities were limited, and set requirements that were beyond our actual strength.