If you know good jeans, you know about Japanese denim. Perhaps no brand has garnered as fierce a following as Iron Heart. The so-called “Iron Heart Army” gathers on a clunky old Internet forum, discussing cotton origins, dip-dye varieties, shuttle looms, raw denim fading competitions and the mundanity of daily life. WSJ explores how a 69-year-old Japanese biker built the coveted denim brand. Chapters: 0:00 The denim obsession 1:24 Iron Heart’s origins 2:40 The rise of Japanese denim 4:33 The denim capital of Japan 5:28 How the denim is made 8:07 The denimhead community 12:20 The future of Iron Heart WSJ's Coveted highlights the precision and process behind expertly-crafted cult favorites — from the pencils beloved by Disney animators to the sushi knives breaking thousands of years of Japanese tradition. These stories show how the smallest everyday items can be transformed into the ultimate luxury splurge. #Denim #Jeans #WSJ