[Hatredcopter]

I can tell you they do check your onward/returning ticket, but not every time. It seems to me that it depends on the immigration officer. Now that said, I haven't gone to Japan on a tourist visa for several years now (only student/work visa), and since then, immigration has become stricter (fingerprints, new gaijin cards, etc), so I certainly would not risk going to Japan without a plane ticket if you don't have a long-term visa. I have no idea whether they'd allow you to go in if you proved how much money you had - I doubt anyone here would know the answer to that. I would really recommend calling your embassy/consulate, they can provide a lot more information than people on these forums can.

As for Korea, I've drank tapwater in Korea many times without a problem (although it was only in Seoul/Incheon). I don't know what things are like outside those areas, though.