If you’re going to be here in November, I’d keep my eye on Ruby World Conference. The next one hasn’t been announced yet, but will likely be held sometime in November. Despite offering simultaneous interpretation to English, the attendees and focus of the conference itself seem to be domestic, but this also gives you a great chance to stand out and meet people.
Generally speaking, taking a look at conference sponsors and the companies speakers work at give you an idea of some of the companies looking for Rails developers. Take a look at Ruby Kaigi’s Sponsors for instance. If you find a company there you are enthusiastic about, you could try contacting the company about meeting, even if they aren’t advertising actively that they are looking for someone. If you do this, be sure to pay attention to describe why you want to work for that particular company, and what skills you bring that they could benefit from; mass emailing the companies will get you no where.
I’d also work on making yourself generally more employable as a Rails developer. Generally, the more of a public profile you have, the better. This could be stuff like having an active blog, an application you have as a side project, open source contributions, and so on.
If you’re currently working as a Rails developer, one way you can get into contributing to Rails is to upgrade a production application your working on to an unreleased version. For instance, assuming you have access to an application that’s running Rails 4.2, try changing it to the master branch of Rails (update your Gemfile to
gem 'rails', git: "email@example.com:rails/rails.git"). You’ll probably come across many bugs in the process, some of which will be easily fixable. Upgrading is where most of my contributions came from.
Another thing you can do is try to make a presentation at your local Ruby event. As an event organiser, I’m always happy to have someone offer to present, as finding speakers is one of my biggest challenges. I think the bar is generally fairly low to present at local events, so even if you’re not an expert, there’s room for you to present. You could also then pitch events in Japan on your presentation, as doing a presentation here is a good way to get in front of a bunch of people who might be able to help you find something.
Hope some of these ideas help!