This is a Seiko Third Diver, model "6309-7040." The Third Diver is a mid-production model of automatic divers' watches released around 1976. It features a large, imposing case and is a 150m specification. Based on the serial number 15439, it was manufactured in May 1981. In Japan, it was equipped with the caliber 6306, and overseas with the caliber 6309. Released with the same exterior design, it became a globally popular model. Especially in Europe and America, the index at the 12 o'clock position on the dial was popular for resembling a "sword," and it was called the "sword design." The movement is equipped with a 6-beat automatic caliber (6309). It underwent an overhaul in July 2025 (Reiwa 7), so there is no need to worry about the operational issues typical of vintage watches. The bezel rotates a little loosely but smoothly. The watch stand is for photography purposes and is not included. There are no noticeable scratches, and it is a very clean product for a vintage watch. However, as it is not new, there may be extremely minor scratches that do not appear in the images. Also, as it is a one-of-a-kind vintage item, returns are not accepted to prevent swapping. Please make your purchase after carefully examining the images and fully understanding and agreeing to these conditions.