On this day, 38 years ago, on December 20, 1987 (October 30, 1987 in the lunar calendar), Manwan Hydropower Station: the second largest hydropower station at that time was built in my country. At 6:10 a.m. this morning in 1987, the roaring Lancang River in western Yunnan was cut in half for the first time. The sound of firecrackers in Shanming Valley announced to people that the Manwan Hydropower Station River Closure Project, the second largest hydropower station under construction in my country, was a decisive victory in one fell swoop. Manwan Power Station, located in the middle reaches of the Lancang River, has a designed installed capacity of 1.5 million kilowatts and an annual power generation capacity of 7.76 billion kilowatts. It is one of the key construction projects during the country's "Seventh Five-Year Plan" period. For the first time, this large-scale hydropower project was built as a joint venture between ministries and provinces. It fully implemented the sub-project bidding and contracting system, creating a construction speed that is rare in the history of hydropower construction in my country in the competition. Since construction preparations began in October 1985, builders from all walks of life have completed the workload that normally takes three years to complete in just seven months. The builders of the 14th Hydropower Bureau, who were responsible for the construction of the No. 1 diversion tunnel, worked day and night, setting a national record of 270 meters per month for large-section excavation diversion tunnel. With the joint efforts of nearly 10,000 hydropower builders, the river closure project, originally planned to be carried out by the end of 1988, was advanced by a full year. The water-retaining rock ridge of the diversion tunnel was blasted on the 15th of this month, and the surging river began to divert. At 8 o'clock on the evening of the 18th, the battle to cut off the Lancang River officially began. More than 90 engineering vehicles lined up in a long queue, taking turns dumping gravel, lead wire gabion and reinforced concrete blocks into the roaring river, and building a embankment to advance towards the center of the river. At 3 o'clock in the morning on the 20th, when the Longkou shrank to more than 10 meters, engineers and technicians detonated the container gabion support erected on the cliff on the other side of the river. The container gabion weighing 1200 tons roared and fell towards the Longkou. The interception warriors took advantage of the victory and advanced. Finally, Lancang was subdued before dawn.