There is the so-called ‘blank period of statistics’ from 1940/1941 when thegovernment stopped publishing official statistics to 1953 which was the startingyear of the first National Income estimation of the Bank of Korea(BOK). Thispaper assembled documents and data and estimated the mining andmanufacturing product by items of that period and linked it with the previousand post series to result in long-term series. Mining product was up and downbefore liberation and stagnated during 1st half of 1940s while manufacturingproduct decreased after having peaked at 1941. The product of both miningand manufacturing was increasing to 1949 after great decrease on liberation,The product restarted increase after Korean war’s interruption and the timewhen the product reached the supreme level of colonial period was 1956 inmanufacturing and 1959 in mining. In manufacturing, the share of both food,beverage, and tobacco industry and fiber, clothing, leather, and shoesindustry was 70% and decreased to 60% of manufacturing product andcontinued it after liberation. Being indebted by the development of gold mine,the share of metal mining was 80% of mining product in 1930s, while theshare of coal mining increased finally to reach above 50% of mining productafter liberation.