Does *** the eldest son of Heguo refer to the entire Northeast or just Liaoning Province?

***The eldest son of Heguo generally has two meanings. One is to describe the region: specifically referring to the Northeastern region that has strongly supported the country's construction since the founding of the People's Republic of China. "The eldest son of the Republic of China" refers to the Northeast region. It was first proposed by Mao during his inspection of Harbin. However, Liaoning's being called the "eldest son of the Republic of China" is a historical choice. During the "First Five-Year Plan" period, 24 of the 156 major projects in New China were located in Liaoning. 17% of the country's raw coal, 27% of power generation, and 60% of steel were produced in Liaoning. The first furnace of steel, the first aircraft, and the first More than 1,000 "firsts" in the industrial history of New China, including a giant ship, were born in Liaoning. Therefore, Liaoning also has the reputation of "the cradle of New China's industry" and "the eldest son of the Communist Party of China".