If you are interested in working as a developer in Japan, it's a topic I've written about a bunch: http://www.tokyodev.com/jobs/

One thing you might be clear is whether the positions are for English speakers living in Japan, or if they are open to developers worldwide.

In my experience, most companies where Japanese isn't necessary still prefer people to already be in Japan, as bringing someone from abroad is seeing as more risky, as even if the candidate ends up liking the company, they still might not like life in Japan.