ESL Certification vs Degree

I want to teach English in Japan, and have a couple questions.

1. I've seen a lot of people mention that you need a bachelors degree to get a visa. I've looked at the embassy website and a few more "official" type websites and haven't seen this mentioned. Is the requirement an exaggeration or just an unwritten rule?

2. I don't have a bachelors degree. However I will soon be taking an ESL certification course. Will this be enough.

3. I'm probably going to be taking the course offered by Oxford Seminars. Does anyone know if their classes are good and reputable?

Nolan,

1. I've seen a lot of people mention that you need a bachelors degree to get a visa. I've looked at the embassy website and a few more "official" type websites and haven't seen this mentioned. Is the requirement an exaggeration or just an unwritten rule?

It's neither: it is an explicit requirement for most types of work visa. The requirement is waived if applicants have 10 years' of relevant work experience, however.

2. I don't have a bachelors degree. However I will soon be taking an ESL certification course. Will this be enough.

It won't get you a work visa. The ESL certification would just give you an edge over other candidates applying for the same job.
If you qualify, you could consider the Working Holiday Visa route.

1. Yes, to be issued a work visa as an "instructor", you'll need an undergraduate degree. There is an exception if you have 3 or more years of experience in the field, but the final decision is up to the discretion of the consulate, embassy, immigration office where you submit your application. For a working holiday visa, if your country has such an arrangement with Japan, you don't need an undergraduate degree.

2. The university degree will get you the visa and the ESL certificate will help you get a job in my opinion.

3. Sorry, can't comment on this.

There is an exception if you have 3 or more years of experience in the field

So if I taught English in another country for (at least) three years, then I could probably get a working vista for Japan without the degree?

Yes, it's possible. It's at the discretion of Japan Immigration but for teaching 3 years experience is the minimum requirement if you don't have a degree.