As nothing but domestic iron ore of high sulphur and of poor quality was used, pig iron making operation in Japan right after the ternination of the War could not reach the high efficiency of production, despite of the all-out efforts they were making. As the result of rationalization of equipments and strictly-enforced quality control launched in around 1950, however, the 1000 ton blast furnace, the actual production of which had been 800 tons before the War, was able to tap out 1200 tons per day at the highest in the monthly average in 1954. The average coke ratio in Japan came down below 700 kg. per ton of pig iron, and that of Yawata Works since Sept.1954 has kept up the bright record of 680 kg, surpassing the world level.
The present author explained that this advancement was brougnt about chiefly by the improvement of facilities and the quality control of coke as well as by the increased ratio of sinter in the burden of B. F. A mention is also made of the technical progress achieved in Yawata Works.