I just asked AI (Copilot) and got this.
Japan actively developed and expanded its coal industry prior to World War II. During the Meiji period (starting in 1868), coal became a cornerstone of Japan’s industrialization. The country’s main coal reserves were located in Kyūshū, which supported the growth of the iron and steel industries, and in Hokkaidō, where the coal was of higher quality.
By the early 20th century, Japan had become one of the largest coal producers in Asia, outpacing even China and India in output before the war. Coal was essential not only for domestic energy and industry but also for fueling Japan’s growing military and naval power. However, the mining conditions were often harsh, and the industry had a dual structure: large, mechanized mines run by industrial conglomerates, and smaller, labor-intensive operations.
Japan’s interest in securing additional coal resources also influenced its expansionist policies, including its incursions into China in the 1930s, where access to coal and other raw materials was a strategic objective.