Since I have been here, I have seen times where a lot of jobs will open up quickly because several teachers just happened to decide to leave. You just need to be in the right place at the right time in Japan. It's clean and healthy. Remember the Japanese have the longest life span in the world. There are lots of mountains and historic places to see, but if you have traveled elswehere in Asia, Japan will often seem more like a western country than an eastern one.
Weather is mild in the winter and hot and humid in the summer.
We also have a rainy season and after it, the cockroaches really come out. You hear of very few problems in Japan. You can get by quite well knowing only the greetings in Japanese. I've been here 4 years, and I'm not proud to say I know only a very little Japanese. That's not to say that if you want to learn you can't.