Japan's labor shortage has pushed the number of people changing jobs and employers during their career to its highest level since the global financial crisis, as companies scramble for workers with experience amid a rapidly-aging economy.

So-called job-hopping goes against the grain of Japan's work culture, where many companies hire graduates and employ them until they retire. But the jobs-for-life system is slowly giving way, as society shifts and firms curb labor costs.

Switching jobs for better conditions is no longer taboo within the tightening labor market, and the trend is being led by mid-career workers.