Before Korea's liberation from the Japanese imperialists' colonial rule, the Pothong River in Pyongyang was a river of evil as it had flooded surrounding villages and farm fields in rainy season every year, taking lots of lives.

Fathoming the inhabitants' deep-seated enmity towards the river after the country's liberation, President Kim Il Sung decided to start the grand nature-remaking work for building a prosperous, independent and sovereign state with the Pothong River improvement project and aroused the popular masses to the project.

At a ceremony for starting the project on May 21, Juche 35 (1946), he said that the success in building a democratic Korea entirely depends on its people's own efforts and enthusiasm. And he encouraged the people, stressing that we should finish such projects one by one with our own efforts.

With this spirit of self-reliance he implanted, breaking ground first to signal the start of the project, the Korean people turned out as one in the patriotic nature-remaking project. They removed more than 420,000 cubic meters of earth and built a 5 km-long embankment to finish in a matter of 55 days the huge project, which the Japanese imperialists failed to complete even after 10 years of effort with the mobilization of as many as 3 million people.

Thanks to the completion of the project, the Pothong River became to flow along a new route into the Taedong River, eternally freeing the inhabitants in the area from worry about flooding.

The success in the project was the first victory the Korean people achieved in the great nature transformation by their own efforts under the guidance of the President after the national liberation.