If at all possible, you should start your job search long before you leave for Japan. This way you can apply for a work visa before leaving your home country, and you will not have to change visas in Japan. Switching to a work visa from another form of visa (temporary, for example) while in Japan is difficult. Most employers will not bother to hire someone who does not have definite permission to work, and they will be hesitant toward sponsoring a work visa on such short notice.
Job portals for Japan
Depending on your previous work experience, you may have success with an executive recruitment agency such as Alex Tsukada International or East West Consulting. These agencies specialize in matching qualified management applicants with appropriate positions at Japanese companies. You send these agencies a CV and cover letter for consideration, at which point they will decide whether you are representable. The executive recruiting option will be most useful to those with significant prior management experience. As they work with senior employees, executive recruiting agencies are highly effective and confidential.
Numerous Japanese professional associations serve various industries. The Japan Electronics and Information Technology Industries Association (JEITA) and the Japan Auto Manufacturers´ Association are both examples of major trade associations.
These groups offer industry news and publications, many of which contain job listings. Another benefit to joining (or at least contacting) a professional association is that it may provide you with an opportunity to make personal contacts with colleagues and employers. In the Japanese business world, connections (kone) are a valuable resource, especially for a foreigner. Those Japanese employers or colleagues with whom you can develop personal relationships are far more likely to hire you, and even more importantly, to sponsor your work visa.
EU Executive Training Programme (ETP)
If you are from a European Union member nation, the EU ETP offers you the opportunity to apply for 18 months of training and work in Japan. The program is selective and geared toward corporate executives, but it is notable for providing language help and a significant stipend to its participants.
Finally, international job listings appear in major newspapers such as The Financial Times and The International Herald Tribune. While these publications offer a broader range of listings for numerous countries, it can´t hurt to take a look to see what sort of positions are in demand on the international market.
For more focused newspaper listings, see the Japan Times, the major English-language newspaper published in Japan.
If you can read Japanese, you will surely want to look at some of the Japanese-language papers for additional listings.
Teaching English in Japan
No matter what your ultimate goal for employment in Japan, you might want to consider teaching English, at least when you first arrive. This will allow you to obtain a work visa, and while you are teaching you will have time to improve your Japanese, which will make you a much more attractive candidate for future employment.
Websites with job listings and other resources for prospective English teachers include TEFL and Aeon – Teaching English in Japan. TEFL has listings for English teaching positions around the world (including Japan), while Aeon is a major English school inside Japan. Many teaching positions do not require prior teaching experience, though most will require some form of degree.