Last week, the World Toilet Association (sign me up for that club) held it's conference in Seoul, to promote better sanitation. Here is my advice for travelers to Asia based on my own visits to Korea, China, and Vietnam: Don't let your pant legs drag when you enter the water closets/port-o-potties/restrooms. There is no guarantee that there will be soap or toilet paper in the restrooms. I advise traveling with a small wad of toilet paper and some hand sanitizer. At least in Asia there's a lot of bowing and not much hand shaking!
