As years of near-zero interest rates in Japan make traditional lending barely profitable, one regional bank is seeking to drum up business through less conventional enterprises, from opening wine bars to helping fishermen farm sea urchins.

The new approach comes as regulators cautiously loosen the rules to let banks venture into other businesses to help offset the hit to their net interest income from the Bank of Japan's ultraloose monetary policy.

For Takeshi Yoshimura, the 59-year-old president of Yamaguchi Financial Group, the effects of the BOJ's zero interest rates are compounded by other challenges his region faces, notably a dwindling population and an exodus of firms to bigger cities like Tokyo.