I've been researching sending off my 4s15 diver and possibly my flightmaster auto to Japan for service. I had E-mailed Yserve and they wrote back saying to send the watch to Co-serve. I thought I was clear in my E-mail they were Japan only watches and needed to go back to Japan. So I thought what the heck and called Co-serve and they said they were familiar with both watches and would repair them there and if need be would order parts or ship them off to Japan. They said those watches have come through there before. I have a bad feeling about sending either one to Co-serve. I think I'll contact Seiya and go that route.