Extensive drifting Motion of snow left Self_motion communities isolated Preventing_or_letting and unable to receive Receiving deliveries Sending of food and heating fuel .

Võ Nguyên Giáp , however , used Using efficient and novel tactics of direct fire artillery , convoy Patrolling ambushes and massed anti-aircraft guns to impede land and air supply Supply deliveries together with a strategy based on recruiting a sizable regular army facilitated Cause_to_make_progress by wide popular support Supporting , a guerrilla warfare doctrine and instruction developed Coming_to_be in China , and the use Using of simple and reliable war material provided Supply by the Soviet Union .