Since 2006, experiments in iron manufacture were continuously carried out at Archaeology Laboratory of the Hiroshima University’s Graduate School of Letters. This was part of a broader research project on ancient iron production. In September 2014, we used two earthen charcoal braziers to fashion simple smelting furnaces. A ventilator maintained airflow, and we layered limonite (brown hematite) and charcoal into the furnaces, for purposes of smelting. We performed two experiments each lasting two hours. In the first experiment, we maintained a temperature of around 1150°C at the base of the furnace, and used a total of 500g of limonite ore. In the second, we maintained a temperature of around 1200°C, and used a total of 960g of limonite ore. In both experiments, we observed changes in the products. The experiments yielded approximately 66.2g of a ferruginous substance in the first operation, and 84.9g in the second. We conducted a comparative analysis of the two smelting operations, and noted differences in the size and magnetic responses between them.