I was reading some Japan Institute of Labour surveys (again) and created a graph to help illustrate the challenge of finding candidates in Japan. Every recruiter knows this struggle.

Less than 8% of employees in Japan came into their job within the past year (survey from 2015) and over 45% of employees have been in the same job for 10 years or more. This helps explain the lack of candidates applying to all those jobs!!
You need a compelling story to attract candidates from this very limited supply. That story needs to be delivered by competent recruiters who can be trusted to deliver the message.