Launched in 1999. These are reproduction jeans based on the concept of Levi's Japan recreating the 501 from the early 1950s. When they were first released, the reproduction jeans made by Levi's Japan couldn't be given the lot number 501XX, so they were named 50SXX (meaning 1950s) with a touch of regret. Although these jeans are no longer in production, they have a strong emphasis on the fabric, and there are still Levi's fans who seek them out. These are the jeans I purchased in 1999 and have worn and stored. The hem has not been altered. They have chain stitching. The button back stamp is J09. Thank you.