There are several methods available. Job sites, recruitment agencies or networking are some examples. There several kinds of job sites. If you are able to speak Japanese, checking the sites Japanese job seekers themselves usually use (Rikunabi, Bizreach, Mynabi) will enable you to learn about popular firms and occupations. If you can’t speak Japanese, try checking sites that cater to English speakers such as Indeed, Wantedly, Daijob. In addition, from major companies to start-ups, there are a host of recruiting agencies. There are 20,000 companies each with their own differing strengths and specialities. Choose based on whether they handle positions that suit you and the availability of consultants.