PET means polyethylene terephthalate, and it's just referred to as PET in Japan.
Apparently, you're supposed to remove the cap when you recycle a PET bottle. I only fully realized that today. Oops. Of course, that means that the lovely plastic cap does not get recycled, which is a bad thing.
Like we need more plastic which degrades very verrry slowly (slower than George Bush's brain, can you imagine that?) cluttering up the world. At least the aluminum bottles get completely recycled (I think). I will have to stop using PET bottles.