Millennials in Japan have little interest in the job-hopping ways of their overseas counterparts, seeking stability and security instead. That is thwarting the Bank of Japan's efforts to jolt the economy back to life.

By some measures, young Japanese today face the best job market in a generation, with unemployment at a two-decade low of 2.8 percent. Offers of coveted permanent positions are on the rise. Yet last year only 6.9 percent of those in the 25-to-34 age group switched jobs.

That's a problem for the BOJ as it tries to stoke inflation and growth with its unprecedented monetary stimulus. After four years, the central bank is still waiting for the wage increases it says will fuel higher prices. Low worker mobility and a "strong preference for job security" are two of the biggest obstacles to that happening in Japan, according the International Monetary Fund.