Summarize the following:
Having at least a bachelor's degree is a requirement. This is not a requirement for the job, but rather for the work visa. Without a work visa (or a spouse visa if you are married to a Japanese citizen) you cannot legally work in Japan. This is an immigration law. Without a bachelor's degree, Japan will not issue you a work visa. You don't want to break the law in Japan. If you are caught working without a visa you will be detained and deported. Your bachelor's degree doesn't need to be in English or teaching, but it might be more useful. Any bachelor's degree will do. If you do want to work in Japan then you will need a lot of money. It is recommended to bring at least $2,000 with you to help you get started before you get your first paycheck. In addition, you will need to buy suits for your job. Most schools will require you to wear a suit, but some let you take off the suit jacket in the classroom, especially during summer time. You should have at least 3 nice suits. Also, you will have to pay for your plane tickets. Depending on your interview location, you may need to fly there (even within your own country). You also need to pay for your own flight to Japan. In other words, no arrests. The government will not issue a visa to someone who has committed a crime. Small crimes several years ago may be overlooked, but anything in the past 5 years is almost a guarantee than your visa will be denied.

Summary:
Earn a bachelor's degree. Start saving money. Have a clean past.