Operation Pollux was a military operation during the First Indochina War by the French forces in northwest Vietnam in November and December 1953 was one of a twin operation, the other being Operation Castor. The names of these operations are based upon the mythological twins, Castor and Pollux. Operation Castor recaptured and then established a fortified airfield in Điện Biên Phu, in the north-west corner of Vietnam. Operation Pollux was the name of the second operation (the evacuation of Lai Châu to Dien Bien Phu), which took place weeks later. These operations were developed by General Navarre who had replaced General Salan as Commander in Chief in early 1953 after the Viet Minh had conducted their successful offensive in the Black River area of northwest Vietnam and then subsequently invaded Laos in April 1953.