Before getting into it, let’s first understand Your Japanese working visa is valid until it expires, even if you change your job. If you change jobs, for whatever reason, your former employer cannot take your visa away, and you can work at a new company if the type of activities remains the same. However, the Immigration office has the authority to revoke your visa if you don't find a new job within 3 months after you leave your previous job. If you wish to change your job to a job outside the scope of activities defined by your status of residence, you must do your own “Application for Change of Status of Residence” by yourself before changing jobs. You can apply to that change at any time during the period of stay. As long as you have time left on your working visa, you can usually stay in Japan for up to three months without being employed. So, it's not a problem if you want to have a month or two off in Japan after quitting, but you are legally required to inform Immigration within 14 days of your last official workday. The process of serving a notice period before leaving a job depends on the company to company but in general it is almost same as any other country.