The Japanese Straightening System, also known as thermal reconditioning, is a permanent hair straightening treatment that transforms curly, wavy, or frizzy hair into sleek, pin-straight locks. The process involves applying a chemical solution that breaks down the bonds in the hair, followed by flat ironing and a neutralizer to “freeze” the new structure in place. The treatment lasts until the hair grows out, requiring touch-ups as new hair emerges.