This study proposes a new hypothesis (multiplicity of production structure) on the structure and characteristics of the Joseon steel industry in wartime, with focus on the anthracite iron business that had been run since 1943 by Riwon Cheolsan Corporation, the largest steel company in Joseon during the interwar period. Actually, since 1943, Riwon Cheolsan had been a major unit of the small-blast-furnace iron-making project the imperial government pushed forward in the Joseon territory. The steel company executed the construction of a steel mill with five 20-ton blast furnaces with loan funds from international financial institutions, Industrial Facilities Corporation and Wartime Financial Bank. However, unlike initially planned, the construction and operation of the steel mill made slow progress due to technical problems in anthracite iron-making and wartime shortages of materials. Accordingly, it was inevitable to accumulate capital rapidly through loan finance. Such poor performance of the iron-making business was mostly attributed to the intrinsic characteristics of the anthracite iron-making process scientific experimental research. So to speak, the use of anthracite coal with low burst strength as fuel for steel mill operations hindered the reducing process in blast furnaces and thus the steel mill required design alterations and additional investment in facility extension. Nippon Steel Corporation`s Cheongjin steelworks during wartime featured the modern steel technology of large-blast-furnace iron-making based on economies of scale, whereas the anthracite iron-making process of Riwon Cheolsan just relied on incomplete technology lacking economic rationality. Consequently, Nippon Steel Corporation`s Cheongjin steelworks can be characterized as a peacetime economic model, while Riwon Cheolsan`s anthracite steel mill can be considered to represent a wartime economic model characterized by abnormality and imbalance in wartime.