In the 1940s, when denim jackets were not called jean jackets, they were called pleated blouses. The design of the front pleats is reminiscent of the 1800s. After being woven, the fabric that was not pre-shrunk shrinks well in the vertical direction. In the 1800s, the fabric was sewn horizontally, and when it shrunk after washing, the pleats could be removed to increase the width. It is also said. Even after the specification of using the fabric in the vertical direction, only the design remains, and even today it is inherited as the design of the front pleats. Denim in the 1940s tends to have longer vertical unevenness than denim in later years. I'm not sure if it's because the way the fibers are crushed differs depending on whether the raw cotton was hand-picked or machine-picked, but denim before the 1940s and denim in the 1950s have different uneven expressions. The original denim used for orslow6011 also uses a material with longer vertical unevenness than others. The back specifications are T-back specifications for sizes 3 and above. It seems that this specification was devised to improve the handling of large-sized fabrics in an era when things were valuable and used without waste.