Early in the period of the anti-Japanese armed struggle, he defined it as one of the major tasks facing a ruling working-class party to realize independence in the economy as well as in politics.

Since the country's liberation from the Japanese colonial rule, he had constantly adhered to the line in building the nation's economy, the line that calls for building the economy in reliance on the nation's efforts, technologies and resources.

In late Juche 39 (1950) when the country was in the thick of war, he set forth a policy on preparing for the postwar reconstruction, indicating fundamental ways to that effect.

At the 6th plenary meeting of the Central Committee of the Workers' Party of Korea, held some days after the war, he laid down a basic line of building the economy, the line of building a self-supporting national economy, which called for giving priority to the development of heavy industry while simultaneously developing light industry and agriculture.

In hearty response to the line, workers of the Kangson Steel Plant turned out 120,000 tonnes of rolled steel at a blooming mill with a rated capacity of 60,000 tonnes and those of the Kim Chaek Iron Works produced 270,000 tonnes of pig iron at facilities with a rated capacity of 190,000 tonnes.

A first home-made tractor came out in 30 days, a truck in 40 days to be followed by manufacture of excavator and bulldozer.

Local workers also succeeded in making 8-meter turning lathe and 3,000-tonnes press.

Pyongyang City builders assembled 20 000 flats with materials, funds and man power for 7 000 flats, while machinery workers made an electric locomotive by themselves.