#Ruka's Watch Seiko Quartz 6431-5100 Gold Color Operation confirmed. Fully functional. New battery replaced, simple cleaning done. New strap replaced! Based on the serial number, it appears to be a 1981 model. Please check the condition in the images. Crystal has scratches. Case size is approximately 31mm, lug width 18mm. Currently, this is the only one listed on the flea market site, so it's a rare item. If you want it, please don't hesitate. If you like it, please give it a like! I would also appreciate it if you would follow me! Regarding items with confirmed operation, I have checked the basic functions, but I haven't done a detailed check, so please understand. I want you to be satisfied as much as possible, so I check what I can, but it is sold as-is. Returns are not accepted due to customer circumstances. If you feel any anxiety about the condition, please refrain from purchasing. *The display stands, etc., used in the photos are not included. Immediate purchase and silent transactions are also given a "good rating," so please rest assured. Thank you for your understanding. Search words Quartz, stylish, antique, vintage, North American style, gold watch, leather strap, rubber strap, contemporary art, vintage, retro, stainless steel, divers watch, study, exam, outdoor, camping, simple, chic, formal, entrance ceremony, graduation ceremony, dress, chronograph, men's, women's, wristwatch, Showa retro, Heisei retro, art, design, art, fashion, Taisho modern, tank